Re: [RE-wrenches] intermittent battery problem; ...Battery Sulfation
Ron, I'm going to reiterate what Jeff says here. It is similar to what I had said in my email. The charge rate must REGULARLY be C10 on the KS (5000 series) batteries. This means, on KS 25's, a routine bulk charging rate of 135 amps. I find that on these types of hybrid systems, while the batteries might occasionally (sunny day, generator running, etc.) that kind of charging, they do not regularly see C10. I think if you gave Jamie Surrette a call he would give you the same possible assessment. I do think the problem is oversulfation, but none of this solves your problem, I know. We have been installing KS series batteries since they came out and this necessity of regular C10 charging has been an integral part of design for me for many years. Best, Daryl Ron, This reply a little late since I have been off line a few days. I mentioned in a similar thread last year that I had an off grid home client I designed and installed in Idaho back in 1998 that had a Kohler 8.5 kw generator, a Trace 4024 inverter, two separate solar arrays and Outback charge controllers, and 16 Trojan L-16 batteries. This system worked flawlessly for 7 years and only required the generator a few hours per month, then it was time to change the batteries. I replaced the Trojans with the same size battery made by Surrette and everything went to crap. They had to run the generator hours and hours to get them past an 80% charge and we had lots of problems with overloading the generator even though we did not make any program changes and used the same generator. The generator was replaced 2 years later but this system never worked like it did before the battery replacement. When researching all this at that time I had talked with Surrette, Trojan, and anyone else that might help and this is what I found out. Of course there are just my opinions based on these conversations, but it is my understanding that Surrette is a much longer life battery with much less water loss when comparing apples and apples, and I was told this was due to a different lead composition that Surrette uses than any other battery manufacturer. However, this difference requires a much longer absorption/taper off charge process or you will never get it past 80% charged. This of course is almost impossible to achieve with a generator or undersized solar array, and you really need a grid connection to fully charge these things. No doubt these would be great in some standby grid connected system but I no longer use them in off grid. This was also at a time when battery manufacturers were just discovering solar so maybe battery designs have changed. Again, I think Surrette is a good company and makes a great battery, but just not sure you can fully recharge them with a mid-sized generator. I also do not like using parallel battery layouts as its hard to keep one string from pulling down the other strings when there is a low performance cell so you might do a cell by cell check. Good Luck, Jeff Yago DTI Solar Inc. --- This is not what I expected after a lengthy EQ. I'm getting them to do another one tomorrow after a discharge cycle and charge but I'm really beginning to think we have something else going on here, something electrical, not chemical. The rapid voltage drop is puzzling. To review, it's an Outback 3524 on an Epanel, Whisper 100 controller, 6 4KS 25 Surrette batteries in 24v configuration - 4.5 years old, .7kw solar. I know the charging end is undersized but they have been compensating with the generator and they get lots of wind in the fall, winter, spring. ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] intermittent battery problem; ...Battery Sulfation
Todd, I asked Surrette about their lead calcium batteries this morning, right after reading your post. Here's their reply: I'm afraid our flooded calcium line is not yet available. Product testing went very well but at this time our present high demand for our other product lines has prevented us from moving forward on this new product line. At this time there is no estimated production date for a flooded calcium line. Bummer. Dick Ratico Solarwind Electric --- You wrote: I digress but... the best battery for grid tie with backup is not lead antimony, but lead calcuum. Surrette makes these too and they use next to no water and have a much longer warrantied life. Todd On Wednesday, November 16, 2011 6:52pm, Jeff Yago jry...@dtisolar.com said: No doubt these would be great in some standby grid connected system but I no longer use them in off grid. This was also at a time when battery manufacturers were just discovering solar so maybe battery designs have changed. Sent from Finest Planet WebMail. --- end of quote --- ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] intermittent battery problem; ...Battery Sulfation
Todd, I thought you were totally off-grid. Mark Frye Berkeley Solar Electric Systems 303 Redbud Way Nevada City, CA 95959 (530) 401-8024 http://www.berkeleysolar.com/ www.berkeleysolar.com _ From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of toddc...@finestplanet.com Sent: Thursday, November 17, 2011 12:25 PM To: RE-wrenches Subject: Re: [RE-wrenches] intermittent battery problem; ...Battery Sulfation wow, thanks for the information. hopefully they will have them in production in 20 years when my current beta set finally dies. cd and others make em, but they are more expensive. todd ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] intermittent battery problem; ...Battery Sulfation
Hi Mark, I have been grid tied (zero energy since 2004) for 15 years. I used to live off grid before I moved here to this home 17 years ago. Todd On Thursday, November 17, 2011 12:36pm, Mark Frye ma...@berkeleysolar.com said: Todd, I thought you were totally off-grid. Mark Frye Berkeley Solar Electric Systems 303 Redbud Way Nevada City, CA 95959 (530) 401-8024 [http://www.berkeleysolar.com/] www.berkeleysolar.com From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of toddc...@finestplanet.com Sent: Thursday, November 17, 2011 12:25 PM To: RE-wrenches Subject: Re: [RE-wrenches] intermittent battery problem; ...Battery Sulfation wow, thanks for the information. hopefully they will have them in production in 20 years when my current beta set finally dies. cd and others make em, but they are more expensive. todd Sent from Finest Planet WebMail. ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] intermittent battery problem; ...Battery Sulfation
Hi Larry, no amp hour meter installed yet as the customer is penny pinching. We're trying to solve the problem first and I've been out there twice, once to do general diagnostics and check all connections, try to load test the batteries, and so on; the second time I 'dropped in' to try a different load test on the batteries to see if I could replicate the problem and to resolve some other problems with a Whisper controller that had given up the ghost when disconnected re-connected to the batteries (all precautions taken). It's a seven hour round trip and with time spent on the job makes for an expensive service call. I only charged for one call and I have to go back at least once more. So customer wanted to save some money on the installation of the TriMetric until the spring... sorry for the long winded reply. I know, it's false economy. So I'm thinking I'll just put the meter in and tell them to pay me when they feel like it. It'll help solve the problem and get some of the Wrenches off my back ... ;-) Ron Young On 2011-11-13, at 8:26 AM, la...@starlightsolar.com la...@starlightsolar.com wrote: Ron, I stick by my evaluation as seen here: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/msg10694.html The #1 reason for my opinion is that you can NOT drive up voltage on a healthy bank that size in just 5 minutes. It is impossible with a 2500 watt generator. Here is the pertinent part from my post: You mentioned that the the battery drops to 24.5 in the early AM without any heavy loads on. For the 4KS25 battery this equates to about 800AH at the 72 hour rate. Then you said that the customer ran a 2500 watt generator for 5 minutes and drove the voltage up to 29 volts. Here's the Ah-Ha moment: That is EXACTLY the behavior of a heavily sulfated battery bank. A fast rise in voltage indicates sulfation. It is impossible for that tiny generator, or any charge source they own for that matter, to replace the hundreds of AH it would take to drive a healthy battery up to the absorb voltage of 29 volts. The bank is about 45,000 watt hours (72h rate). There would have to be over 20,000 Wh removed to be at that voltage. How many Wh's are replaced in 5 minutes by a 2500 watt genny? I'm sure you are getting the picture. Also, why have you not installed a battery monitor yet? It will give you eyes into the battery and spare countless hours of time diagnosing the problem. Larry Original Message Subject: Re: [RE-wrenches] intermittent battery problem; ...Battery Sulfation From: Ron Young solarea...@solareagle.com Date: Sat, November 12, 2011 9:57 pm To: RE-wrenches re-wrenches@lists.re-wrenches.org Folks, this one really has me puzzled. The client has done regular two hour EQ's, at least once a month. When did a site visit and I topped up the electrolyte (they'd been starving the batteries for water but always just above the plates) the problem seemed to go away. They were satisfied that the problem was solved but I wasn't and I told them what I had been hearing from this group - essentially that the batteries needed a deep EQ, discharge, recharge and EQ again two or three times to scrub the sulphates. They declined until just a few days ago when they said the rapid voltage drop was back. Here's a quote: We had another rapid voltage loss this morning ---it was 25.2 when we got up and it dropped rapidly to 22.8. We turned on the generator and charged the batteries until our display showed 30.2 for awhile with the generator running. We turned off the generator and the voltage settled at about 26.4. We turned off all loads and wind and solar. At 9.15 our batteries were at 26.4 At 9:16 we turned on an 8W light bulb, a1600W hair dryer, and a 1.5HP (120V 5.75A) shop vac The display showed a load of 1.9kw At 9:40 the inverter shut down---display showed batteries at 18.4 By 9.47 the display showed the batteries at 25.2the solar and wind were still shut down. We turned everything back on (a light, Sunfrost RF16, phone) and all seems to be normal. They agreed to do the EQ process but only have a 3kw generator so we started with 8 hours with the EQ voltage set for 32v (24v system). They completed that yesterday and here's what resulted: Before starting EQ the batteries were at 25.8, hydrometer reading 1283 with temp. correction Began EQ32.6 v Buying 1.5 kw Hour 1 32.4 v 1283 with temp. correction Buying 1.4 Hour 2 32.4 v 1285 with temp. correction Buying 1.5 Hour 3 32.2 v
Re: [RE-wrenches] intermittent battery problem; ...Battery Sulfation
Hi Daryl. I've got other KS25's in hybrid systems (wind gen solar) that seem to do fine over the last several years. The Ouback 3524 has an 85 amp charger. There was no problem getting to 32 v and holding it for eight hours. This has been done twice now. Larry and others attribute the ability to get to 32v to a sulphated battery condition and I'm thinking that a healthy battery could get to 32v as well, especially one that's been regularly EQ'd... am I wrong? I'm listening to every opinion here and trying to sort it out but I think John may be on the right track with an intermittent failure of one cell. I just can't seem to find it. Ron Young On 2011-11-13, at 3:51 AM, penobscotso...@midmaine.com wrote: Ron, What comes to mind for me is that Surrette 5000 series batteries like to have a regular charge of C10. KS25 cells are rated for 1350 ah, creating a need for a somewhat regularly occurring charge of 135 amps. I do believe the batteries are not ever getting that, except for very rare occasions. We have seen this before in undersized systems. Is the bulk charge set to 29.6? I would try a couple more eq's over the next month to loosen likely sulfation. Get it up to as close to 32 volts as possible and taper the charge down, then eq at that voltage for four or five hours, even more if the client will do it. That would be how we would deal with this. It does seem ultimately to be sulfation that is the problem. Daryl DeJoy NABCEP Certified PV installer Penobscot Solar Design Folks, this one really has me puzzled. The client has done regular two hour EQ's, at least once a month. When did a site visit and I topped up the electrolyte (they'd been starving the batteries for water but always just above the plates) the problem seemed to go away. They were satisfied that the problem was solved but I wasn't and I told them what I had been hearing from this group - essentially that the batteries needed a deep EQ, discharge, recharge and EQ again two or three times to scrub the sulphates. They declined until just a few days ago when they said the rapid voltage drop was back. Here's a quote: We had another rapid voltage loss this morning ---it was 25.2 when we got up and it dropped rapidly to 22.8. We turned on the generator and charged the batteries until our display showed 30.2 for awhile with the generator running. We turned off the generator and the voltage settled at about 26.4. We turned off all loads and wind and solar. At 9.15 our batteries were at 26.4 At 9:16 we turned on an 8W light bulb, a1600W hair dryer, and a 1.5HP (120V 5.75A) shop vac The display showed a load of 1.9kw At 9:40 the inverter shut down---display showed batteries at 18.4 By 9.47 the display showed the batteries at 25.2the solar and wind were still shut down. We turned everything back on (a light, Sunfrost RF16, phone) and all seems to be normal. They agreed to do the EQ process but only have a 3kw generator so we started with 8 hours with the EQ voltage set for 32v (24v system). They completed that yesterday and here's what resulted: Before starting EQ the batteries were at 25.8, hydrometer reading 1283 with temp. correction Began EQ32.6 v Buying 1.5 kw Hour 1 32.4 v 1283 with temp. correction Buying 1.4 Hour 2 32.4 v 1285 with temp. correction Buying 1.5 Hour 3 32.2 v Buying 1.7 Hour 4 32.2 v 1290 with temp correctionBuying 1.8 HOur 5 32.0 v 1290 with temp correctionBuying 1.8 Hour 6 32.0 v Buying 1.9 Hour 7 31.8 v 1292 with temp correctonBuying 1.9 Hour 8 complete---turned off Gen and turned on loads ---Batteries dropped to 25.4 within 30 minutes and stayed there until this morning---fridge was running, telephone, internet, wool carding machine, lights. This morning hydrometer reading was at 1290. Then today I just got this email: Just experienced another rapid voltage drop. As soon as the voltage hits 24.8 the voltage drops like a rock if we don't have any input (no solar or wind). This is not what I expected after a lengthy EQ. I'm getting them to do another one tomorrow after a discharge cycle and charge but I'm really beginning to think we have something else going on here, something electrical, not
Re: [RE-wrenches] intermittent battery problem; ...Battery Sulfation
We are only on your back until you to do the advisable thing: Sell them a battery capacity monitor. It is a hard fact that NO off grid, battery based power system should be without a battery capacity monitor. They are cheap (only $150!) and not an option. Apparently, it is also hard learned fact. ;-) Larry Crutcher Starlight Solar Power Systems On Nov 16, 2011, at 12:20 AM, Ron Young wrote: Hi Larry, no amp hour meter installed yet as the customer is penny pinching. We're trying to solve the problem first and I've been out there twice, once to do general diagnostics and check all connections, try to load test the batteries, and so on; the second time I 'dropped in' to try a different load test on the batteries to see if I could replicate the problem and to resolve some other problems with a Whisper controller that had given up the ghost when disconnected re-connected to the batteries (all precautions taken). It's a seven hour round trip and with time spent on the job makes for an expensive service call. I only charged for one call and I have to go back at least once more. So customer wanted to save some money on the installation of the TriMetric until the spring... sorry for the long winded reply. I know, it's false economy. So I'm thinking I'll just put the meter in and tell them to pay me when they feel like it. It'll help solve the problem and get some of the Wrenches off my back ... ;-) Ron Young On 2011-11-13, at 8:26 AM, la...@starlightsolar.com la...@starlightsolar.com wrote: Ron, I stick by my evaluation as seen here: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/msg10694.html The #1 reason for my opinion is that you can NOT drive up voltage on a healthy bank that size in just 5 minutes. It is impossible with a 2500 watt generator. Here is the pertinent part from my post: You mentioned that the the battery drops to 24.5 in the early AM without any heavy loads on. For the 4KS25 battery this equates to about 800AH at the 72 hour rate. Then you said that the customer ran a 2500 watt generator for 5 minutes and drove the voltage up to 29 volts. Here's the Ah-Ha moment: That is EXACTLY the behavior of a heavily sulfated battery bank. A fast rise in voltage indicates sulfation. It is impossible for that tiny generator, or any charge source they own for that matter, to replace the hundreds of AH it would take to drive a healthy battery up to the absorb voltage of 29 volts. The bank is about 45,000 watt hours (72h rate). There would have to be over 20,000 Wh removed to be at that voltage. How many Wh's are replaced in 5 minutes by a 2500 watt genny? I'm sure you are getting the picture. Also, why have you not installed a battery monitor yet? It will give you eyes into the battery and spare countless hours of time diagnosing the problem. Larry Original Message Subject: Re: [RE-wrenches] intermittent battery problem; ...Battery Sulfation From: Ron Young solarea...@solareagle.com Date: Sat, November 12, 2011 9:57 pm To: RE-wrenches re-wrenches@lists.re-wrenches.org Folks, this one really has me puzzled. The client has done regular two hour EQ's, at least once a month. When did a site visit and I topped up the electrolyte (they'd been starving the batteries for water but always just above the plates) the problem seemed to go away. They were satisfied that the problem was solved but I wasn't and I told them what I had been hearing from this group - essentially that the batteries needed a deep EQ, discharge, recharge and EQ again two or three times to scrub the sulphates. They declined until just a few days ago when they said the rapid voltage drop was back. Here's a quote: We had another rapid voltage loss this morning ---it was 25.2 when we got up and it dropped rapidly to 22.8. We turned on the generator and charged the batteries until our display showed 30.2 for awhile with the generator running. We turned off the generator and the voltage settled at about 26.4. We turned off all loads and wind and solar. At 9.15 our batteries were at 26.4 At 9:16 we turned on an 8W light bulb, a1600W hair dryer, and a 1.5HP (120V 5.75A) shop vac The display showed a load of 1.9kw At 9:40 the inverter shut down---display showed batteries at 18.4 By 9.47 the display showed the batteries at 25.2the solar and wind were still shut down. We turned everything back on (a light, Sunfrost RF16, phone) and all seems to be normal. They agreed to do the EQ process but only have a 3kw generator so we started with 8 hours with the EQ voltage set for 32v (24v system). They completed that yesterday and here's what resulted: Before starting EQ the batteries were at 25.8, hydrometer reading 1283 with temp. correction Began EQ32.6 v
Re: [RE-wrenches] intermittent battery problem; ...Battery Sulfation
Ron, you have misquoted me so yes you are wrong. It is not about getting to 32 volts. Go read it again. On Nov 16, 2011, at 12:20 AM, Ron Young wrote: Hi Daryl. I've got other KS25's in hybrid systems (wind gen solar) that seem to do fine over the last several years. The Ouback 3524 has an 85 amp charger. There was no problem getting to 32 v and holding it for eight hours. This has been done twice now. Larry and others attribute the ability to get to 32v to a sulphated battery condition and I'm thinking that a healthy battery could get to 32v as well, especially one that's been regularly EQ'd... am I wrong? I'm listening to every opinion here and trying to sort it out but I think John may be on the right track with an intermittent failure of one cell. I just can't seem to find it. Ron Young On 2011-11-13, at 3:51 AM, penobscotso...@midmaine.com wrote: Ron, What comes to mind for me is that Surrette 5000 series batteries like to have a regular charge of C10. KS25 cells are rated for 1350 ah, creating a need for a somewhat regularly occurring charge of 135 amps. I do believe the batteries are not ever getting that, except for very rare occasions. We have seen this before in undersized systems. Is the bulk charge set to 29.6? I would try a couple more eq's over the next month to loosen likely sulfation. Get it up to as close to 32 volts as possible and taper the charge down, then eq at that voltage for four or five hours, even more if the client will do it. That would be how we would deal with this. It does seem ultimately to be sulfation that is the problem. Daryl DeJoy NABCEP Certified PV installer Penobscot Solar Design Folks, this one really has me puzzled. The client has done regular two hour EQ's, at least once a month. When did a site visit and I topped up the electrolyte (they'd been starving the batteries for water but always just above the plates) the problem seemed to go away. They were satisfied that the problem was solved but I wasn't and I told them what I had been hearing from this group - essentially that the batteries needed a deep EQ, discharge, recharge and EQ again two or three times to scrub the sulphates. They declined until just a few days ago when they said the rapid voltage drop was back. Here's a quote: We had another rapid voltage loss this morning ---it was 25.2 when we got up and it dropped rapidly to 22.8. We turned on the generator and charged the batteries until our display showed 30.2 for awhile with the generator running. We turned off the generator and the voltage settled at about 26.4. We turned off all loads and wind and solar. At 9.15 our batteries were at 26.4 At 9:16 we turned on an 8W light bulb, a1600W hair dryer, and a 1.5HP (120V 5.75A) shop vac The display showed a load of 1.9kw At 9:40 the inverter shut down---display showed batteries at 18.4 By 9.47 the display showed the batteries at 25.2the solar and wind were still shut down. We turned everything back on (a light, Sunfrost RF16, phone) and all seems to be normal. They agreed to do the EQ process but only have a 3kw generator so we started with 8 hours with the EQ voltage set for 32v (24v system). They completed that yesterday and here's what resulted: Before starting EQ the batteries were at 25.8, hydrometer reading 1283 with temp. correction Began EQ32.6 v Buying 1.5 kw Hour 1 32.4 v 1283 with temp. correction Buying 1.4 Hour 2 32.4 v 1285 with temp. correction Buying 1.5 Hour 3 32.2 v Buying 1.7 Hour 4 32.2 v 1290 with temp correctionBuying 1.8 HOur 5 32.0 v 1290 with temp correctionBuying 1.8 Hour 6 32.0 v Buying 1.9 Hour 7 31.8 v 1292 with temp correctonBuying 1.9 Hour 8 complete---turned off Gen and turned on loads ---Batteries dropped to 25.4 within 30 minutes and stayed there until this morning---fridge was running, telephone, internet, wool carding machine, lights. This morning hydrometer reading was at 1290. Then today I just got this email: Just experienced another rapid voltage drop. As soon as the voltage hits 24.8 the voltage drops like a rock if we don't have any input (no solar or wind). This is not what I expected after a lengthy EQ. I'm getting them to
Re: [RE-wrenches] intermittent battery problem; ...Battery Sulfation
You're correct Larry, my apologies. Been burning the candle at both ends. Thanks for your input. On 2011-11-16, at 9:04 AM, Larry Crutcher, Starlight Solar Power Systems wrote: Ron, you have misquoted me so yes you are wrong. It is not about getting to 32 volts. Go read it again. On Nov 16, 2011, at 12:20 AM, Ron Young wrote: Hi Daryl. I've got other KS25's in hybrid systems (wind gen solar) that seem to do fine over the last several years. The Ouback 3524 has an 85 amp charger. There was no problem getting to 32 v and holding it for eight hours. This has been done twice now. Larry and others attribute the ability to get to 32v to a sulphated battery condition and I'm thinking that a healthy battery could get to 32v as well, especially one that's been regularly EQ'd... am I wrong? I'm listening to every opinion here and trying to sort it out but I think John may be on the right track with an intermittent failure of one cell. I just can't seem to find it. Ron Young On 2011-11-13, at 3:51 AM, penobscotso...@midmaine.com wrote: Ron, What comes to mind for me is that Surrette 5000 series batteries like to have a regular charge of C10. KS25 cells are rated for 1350 ah, creating a need for a somewhat regularly occurring charge of 135 amps. I do believe the batteries are not ever getting that, except for very rare occasions. We have seen this before in undersized systems. Is the bulk charge set to 29.6? I would try a couple more eq's over the next month to loosen likely sulfation. Get it up to as close to 32 volts as possible and taper the charge down, then eq at that voltage for four or five hours, even more if the client will do it. That would be how we would deal with this. It does seem ultimately to be sulfation that is the problem. Daryl DeJoy NABCEP Certified PV installer Penobscot Solar Design Folks, this one really has me puzzled. The client has done regular two hour EQ's, at least once a month. When did a site visit and I topped up the electrolyte (they'd been starving the batteries for water but always just above the plates) the problem seemed to go away. They were satisfied that the problem was solved but I wasn't and I told them what I had been hearing from this group - essentially that the batteries needed a deep EQ, discharge, recharge and EQ again two or three times to scrub the sulphates. They declined until just a few days ago when they said the rapid voltage drop was back. Here's a quote: We had another rapid voltage loss this morning ---it was 25.2 when we got up and it dropped rapidly to 22.8. We turned on the generator and charged the batteries until our display showed 30.2 for awhile with the generator running. We turned off the generator and the voltage settled at about 26.4. We turned off all loads and wind and solar. At 9.15 our batteries were at 26.4 At 9:16 we turned on an 8W light bulb, a1600W hair dryer, and a 1.5HP (120V 5.75A) shop vac The display showed a load of 1.9kw At 9:40 the inverter shut down---display showed batteries at 18.4 By 9.47 the display showed the batteries at 25.2the solar and wind were still shut down. We turned everything back on (a light, Sunfrost RF16, phone) and all seems to be normal. They agreed to do the EQ process but only have a 3kw generator so we started with 8 hours with the EQ voltage set for 32v (24v system). They completed that yesterday and here's what resulted: Before starting EQ the batteries were at 25.8, hydrometer reading 1283 with temp. correction Began EQ32.6 v Buying 1.5 kw Hour 1 32.4 v 1283 with temp. correction Buying 1.4 Hour 2 32.4 v 1285 with temp. correction Buying 1.5 Hour 3 32.2 v Buying 1.7 Hour 4 32.2 v 1290 with temp correctionBuying 1.8 HOur 5 32.0 v 1290 with temp correctionBuying 1.8 Hour 6 32.0 v Buying 1.9 Hour 7 31.8 v 1292 with temp correctonBuying 1.9 Hour 8 complete---turned off Gen and turned on loads ---Batteries dropped to 25.4 within 30 minutes and stayed there until this morning---fridge was running, telephone, internet, wool carding machine, lights. This morning hydrometer reading was at 1290. Then today I just got this email: Just experienced another rapid voltage drop. As
Re: [RE-wrenches] intermittent battery problem; ...Battery Sulfation
Ron, This reply a little late since I have been off line a few days. I mentioned in a similar thread last year that I had an off grid home client I designed and installed in Idaho back in 1998 that had a Kohler 8.5 kw generator, a Trace 4024 inverter, two separate solar arrays and Outback charge controllers, and 16 Trojan L-16 batteries. This system worked flawlessly for 7 years and only required the generator a few hours per month, then it was time to change the batteries. I replaced the Trojans with the same size battery made by Surrette and everything went to crap. They had to run the generator hours and hours to get them past an 80% charge and we had lots of problems with overloading the generator even though we did not make any program changes and used the same generator. The generator was replaced 2 years later but this system never worked like it did before the battery replacement. When researching all this at that time I had talked with Surrette, Trojan, and anyone else that might help and this is what I found out. Of course there are just my opinions based on these conversations, but it is my understanding that Surrette is a much longer life battery with much less water loss when comparing apples and apples, and I was told this was due to a different lead composition that Surrette uses than any other battery manufacturer. However, this difference requires a much longer absorption/taper off charge process or you will never get it past 80% charged. This of course is almost impossible to achieve with a generator or undersized solar array, and you really need a grid connection to fully charge these things. No doubt these would be great in some standby grid connected system but I no longer use them in off grid. This was also at a time when battery manufacturers were just discovering solar so maybe battery designs have changed. Again, I think Surrette is a good company and makes a great battery, but just not sure you can fully recharge them with a mid-sized generator. I also do not like using parallel battery layouts as its hard to keep one string from pulling down the other strings when there is a low performance cell so you might do a cell by cell check. Good Luck, Jeff Yago DTI Solar Inc. --- This is not what I expected after a lengthy EQ. I'm getting them to do another one tomorrow after a discharge cycle and charge but I'm really beginning to think we have something else going on here, something electrical, not chemical. The rapid voltage drop is puzzling. To review, it's an Outback 3524 on an Epanel, Whisper 100 controller, 6 4KS 25 Surrette batteries in 24v configuration - 4.5 years old, .7kw solar. I know the charging end is undersized but they have been compensating with the generator and they get lots of wind in the fall, winter, spring. ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] intermittent battery problem; ...Battery Sulfation
I digress but... the best battery for grid tie with backup is not lead antimony, but lead calcuum. Surrette makes these too and they use next to no water and have a much longer warrantied life. Todd On Wednesday, November 16, 2011 6:52pm, Jeff Yago jry...@dtisolar.com said: No doubt these would be great in some standby grid connected system but I no longer use them in off grid. This was also at a time when battery manufacturers were just discovering solar so maybe battery designs have changed. Sent from Finest Planet WebMail. ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] intermittent battery problem; ...Battery Sulfation
Ron, What comes to mind for me is that Surrette 5000 series batteries like to have a regular charge of C10. KS25 cells are rated for 1350 ah, creating a need for a somewhat regularly occurring charge of 135 amps. I do believe the batteries are not ever getting that, except for very rare occasions. We have seen this before in undersized systems. Is the bulk charge set to 29.6? I would try a couple more eq's over the next month to loosen likely sulfation. Get it up to as close to 32 volts as possible and taper the charge down, then eq at that voltage for four or five hours, even more if the client will do it. That would be how we would deal with this. It does seem ultimately to be sulfation that is the problem. Daryl DeJoy NABCEP Certified PV installer Penobscot Solar Design Folks, this one really has me puzzled. The client has done regular two hour EQ's, at least once a month. When did a site visit and I topped up the electrolyte (they'd been starving the batteries for water but always just above the plates) the problem seemed to go away. They were satisfied that the problem was solved but I wasn't and I told them what I had been hearing from this group - essentially that the batteries needed a deep EQ, discharge, recharge and EQ again two or three times to scrub the sulphates. They declined until just a few days ago when they said the rapid voltage drop was back. Here's a quote: We had another rapid voltage loss this morning ---it was 25.2 when we got up and it dropped rapidly to 22.8. We turned on the generator and charged the batteries until our display showed 30.2 for awhile with the generator running. We turned off the generator and the voltage settled at about 26.4. We turned off all loads and wind and solar. At 9.15 our batteries were at 26.4 At 9:16 we turned on an 8W light bulb, a1600W hair dryer, and a 1.5HP (120V 5.75A) shop vac The display showed a load of 1.9kw At 9:40 the inverter shut down---display showed batteries at 18.4 By 9.47 the display showed the batteries at 25.2the solar and wind were still shut down. We turned everything back on (a light, Sunfrost RF16, phone) and all seems to be normal. They agreed to do the EQ process but only have a 3kw generator so we started with 8 hours with the EQ voltage set for 32v (24v system). They completed that yesterday and here's what resulted: Before starting EQ the batteries were at 25.8, hydrometer reading 1283 with temp. correction Began EQ32.6 v Buying 1.5 kw Hour 1 32.4 v 1283 with temp. correction Buying 1.4 Hour 2 32.4 v 1285 with temp. correction Buying 1.5 Hour 3 32.2 v Buying 1.7 Hour 4 32.2 v 1290 with temp correctionBuying 1.8 HOur 5 32.0 v 1290 with temp correctionBuying 1.8 Hour 6 32.0 v Buying 1.9 Hour 7 31.8 v 1292 with temp correctonBuying 1.9 Hour 8 complete---turned off Gen and turned on loads ---Batteries dropped to 25.4 within 30 minutes and stayed there until this morning---fridge was running, telephone, internet, wool carding machine, lights. This morning hydrometer reading was at 1290. Then today I just got this email: Just experienced another rapid voltage drop. As soon as the voltage hits 24.8 the voltage drops like a rock if we don't have any input (no solar or wind). This is not what I expected after a lengthy EQ. I'm getting them to do another one tomorrow after a discharge cycle and charge but I'm really beginning to think we have something else going on here, something electrical, not chemical. The rapid voltage drop is puzzling. To review, it's an Outback 3524 on an Epanel, Whisper 100 controller, 6 4KS 25 Surrette batteries in 24v configuration - 4.5 years old, .7kw solar. I know the charging end is undersized but they have been compensating with the generator and they get lots of wind in the fall, winter, spring. Any more thoughts on this anyone? Best Regards, Ron Young earthRight Products - Solareagle.com Alternative Energy Solutions ~ Renewable Energy Products On 2011-10-24, at 6:50 AM, Larry Crutcher, Starlight Solar Power Systems wrote: Hi Ron, Accurate SG readings are not simple. Was temperature compensation properly employed? Have they been keeping a log book to identify
Re: [RE-wrenches] intermittent battery problem; ...Battery Sulfation
Hi Ron, Here is what I would do. 1. install a amp hr meter without this you have no idea of what is going in/out. So when they mention the batteries drop rapidly to 22.8, they can now see how many amps are going out. 2. record voltages to 2 decimal places of each battery when these anomalies occur. 3. record amps into battery when doing eq/charge and I agree with John, Jay Peltz Power ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] intermittent battery problem; ...Battery Sulfation
Ron, I stick by my evaluation as seen here: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/msg10694.htmlThe #1 reason for my opinion is that you can NOT drive up voltage on a healthy bank that size in just 5 minutes. It is impossible with a 2500 watt generator. Here is the pertinent part from my post:You mentioned that the the battery drops to 24.5 in the early AM without any heavy loads on. For the 4KS25 battery this equates to about 800AH at the 72 hour rate. Then you said that the customer ran a 2500 watt generator for 5 minutes and drove the voltage up to 29 volts. Here's the Ah-Ha moment: That is EXACTLY the behavior of a heavily sulfated battery bank. A fast rise in voltage indicates sulfation. It is impossible for that tiny generator, or any charge source they own for that matter, to replace the hundreds of AH it would take to drive a healthy battery up to the absorb voltage of 29 volts. The bank is about 45,000 watt hours (72h rate). There would have to be over 20,000 Wh removed to be at that voltage. How many Wh's are replaced in 5 minutes by a 2500 watt genny? I'm sure you are getting the picture. Also, why have you not installed a battery monitor yet? It will give you "eyes" into the battery and spare countless hours of time diagnosing the problem.Larry Original Message Subject: Re: [RE-wrenches] intermittent battery problem; ...Battery Sulfation From: Ron Young solarea...@solareagle.com Date: Sat, November 12, 2011 9:57 pm To: RE-wrenches re-wrenches@lists.re-wrenches.org Folks, this one really has me puzzled. The client has done regular two hour EQ's, at least once a month. When did a site visit and I topped up the electrolyte (they'd been starving the batteries for water but always just above the plates) the problem seemed to go away. They were satisfied that the problem was solved but I wasn't and I told them what I had been hearing from this group - essentially that the batteries needed a deep EQ, discharge, recharge and EQ again two or three times to scrub the sulphates. They declined until just a few days ago when they said the rapid voltage drop was back. Here's a quote:We had another rapid voltage loss this morning ---it was 25.2 when we got up and it dropped rapidly to 22.8. We turned on the generator and charged the batteries until our display showed 30.2 for awhile with the generator running. We turned off the generator and the voltage settled at about 26.4. We turned off all loads and wind and solar.At 9.15 our batteries were at 26.4At 9:16 we turned on an 8W light bulb, a1600W hair dryer, and a 1.5HP (120V 5.75A) shop vacThe display showed a load of 1.9kwAt 9:40 the inverter shut down---display showed batteries at 18.4By 9.47 the display showed the batteries at 25.2the solar and wind were still shut down.We turned everything back on (a light, Sunfrost RF16, phone) and all seems to be normal.They agreed to do the EQ process but only have a 3kw generator so we started with 8 hours with the EQ voltage set for 32v (24v system). They completed that yesterday and here's what resulted:Before starting EQ the batteries were at 25.8, hydrometer reading 1283 with temp. correctionBegan EQ 32.6 v Buying 1.5 kwHour 1 32.4 v 1283 with temp. correctionBuying 1.4Hour 2 32.4 v 1285 with temp. correction Buying 1.5Hour 3 32.2 v Buying 1.7Hour 4 32.2 v 1290 with temp correctionBuying 1.8HOur 5 32.0 v 1290 with temp correctionBuying 1.8Hour 6 32.0 v Buying 1.9Hour 7 31.8 v1292 with temp correctonBuying 1.9Hour 8 complete---turned off Gen and turned on loads ---Batteries dropped to 25.4 within 30 minutes and stayed there until this morning---fridge was running, telephone, internet, wool carding machine, lights. This morning hydrometer reading was at 1290. Then today I just got this email:Just experienced another rapid voltage drop. As soon as the voltage hits 24.8 the voltage drops like a rock if we don't have any input (no solar or wind).This is not what I expected after a lengthy EQ. I'm getting them to do another one tomorrow after a discharge cycle and charge but I'm really beginning to think we have something else going on here, something electrical, not chemical. The rapid voltage drop is puzzling.To review, it's an Outback 3524 on an Epanel, Whisper 100 controller, 6 4KS 25 Surrette batteries in 24v configuration - 4.5 years old, .7kw solar. I know the charging end is undersized but they have been compensating with the generator and they get lots of wind in the fall, winter, spring.Any more thoughts on this anyone?Best Regards,Ron YoungearthRigh
Re: [RE-wrenches] intermittent battery problem; ...Battery Sulfation
Folks, this one really has me puzzled. The client has done regular two hour EQ's, at least once a month. When did a site visit and I topped up the electrolyte (they'd been starving the batteries for water but always just above the plates) the problem seemed to go away. They were satisfied that the problem was solved but I wasn't and I told them what I had been hearing from this group - essentially that the batteries needed a deep EQ, discharge, recharge and EQ again two or three times to scrub the sulphates. They declined until just a few days ago when they said the rapid voltage drop was back. Here's a quote: We had another rapid voltage loss this morning ---it was 25.2 when we got up and it dropped rapidly to 22.8. We turned on the generator and charged the batteries until our display showed 30.2 for awhile with the generator running. We turned off the generator and the voltage settled at about 26.4. We turned off all loads and wind and solar. At 9.15 our batteries were at 26.4 At 9:16 we turned on an 8W light bulb, a1600W hair dryer, and a 1.5HP (120V 5.75A) shop vac The display showed a load of 1.9kw At 9:40 the inverter shut down---display showed batteries at 18.4 By 9.47 the display showed the batteries at 25.2the solar and wind were still shut down. We turned everything back on (a light, Sunfrost RF16, phone) and all seems to be normal. They agreed to do the EQ process but only have a 3kw generator so we started with 8 hours with the EQ voltage set for 32v (24v system). They completed that yesterday and here's what resulted: Before starting EQ the batteries were at 25.8, hydrometer reading 1283 with temp. correction Began EQ32.6 v Buying 1.5 kw Hour 1 32.4 v 1283 with temp. correction Buying 1.4 Hour 2 32.4 v 1285 with temp. correction Buying 1.5 Hour 3 32.2 v Buying 1.7 Hour 4 32.2 v 1290 with temp correctionBuying 1.8 HOur 5 32.0 v 1290 with temp correctionBuying 1.8 Hour 6 32.0 v Buying 1.9 Hour 7 31.8 v 1292 with temp correctonBuying 1.9 Hour 8 complete---turned off Gen and turned on loads ---Batteries dropped to 25.4 within 30 minutes and stayed there until this morning---fridge was running, telephone, internet, wool carding machine, lights. This morning hydrometer reading was at 1290. Then today I just got this email: Just experienced another rapid voltage drop. As soon as the voltage hits 24.8 the voltage drops like a rock if we don't have any input (no solar or wind). This is not what I expected after a lengthy EQ. I'm getting them to do another one tomorrow after a discharge cycle and charge but I'm really beginning to think we have something else going on here, something electrical, not chemical. The rapid voltage drop is puzzling. To review, it's an Outback 3524 on an Epanel, Whisper 100 controller, 6 4KS 25 Surrette batteries in 24v configuration - 4.5 years old, .7kw solar. I know the charging end is undersized but they have been compensating with the generator and they get lots of wind in the fall, winter, spring. Any more thoughts on this anyone? Best Regards, Ron Young earthRight Products - Solareagle.com Alternative Energy Solutions ~ Renewable Energy Products On 2011-10-24, at 6:50 AM, Larry Crutcher, Starlight Solar Power Systems wrote: Hi Ron, Accurate SG readings are not simple. Was temperature compensation properly employed? Have they been keeping a log book to identify changes? How accurate is the hydrometer? How skilled is the person taking the reading? Most of the Battery Wrench responses suggest equalization but I don't see from any of your posts that this has been done yet. I suggest this to be the next step and I recommend that you carefully watch voltage and current. This will tell you a lot. I use a Fluke ScopeMeter in the TrendPlot mode and track voltage and current over time. It provides a good visual understanding. In case others are using this forum to glean information, attached is a chart for illustration of the charge cycle. You should see a constant, somewhat linear rise in voltage until the constant voltage setting is reached. If you see a sudden rise:
Re: [RE-wrenches] intermittent battery problem; ...Battery Sulfation
Hi Larry, I immediately assumed sulphated battery when I heard the customers description a couple of weeks ago but the hydrometer readings didn't jive. Any sulphated battery I've encountered, and I defer to your greater experience, has always revealed itself with a simple S.G. test and these batteries were reading above 1.265. I then thought the possibility of a defective hydrometer and had them test with another but we just got confirmation of the same thing. The weird drop in voltage also isn't explained by your description. Why would this just happen without loads or charging present (except maybe the DC Sunfrost load) at the same predictable time at 4 a.m. The fact that when the generator was turned on and sent a surge of current into the system and the problem went away made the detective in me think there had to be another explanation. The bank was at rest for several hours through the night and the voltage dropout was cured by a brief application of charge current. When I arrived on site my discovery that the client was under watering the batteries and this chronic condition resulted in a very rich electrolyte, reading well above 1.265 - into the 1.280 range made me think that was the problem and it seems to have gone away now that the electrolyte level was raised and the batteries given a good charge. But it still nags at me that something else is lurking in the shadows. Your description of the sulphate converting to a crystalline form has me worried because if this is the case this expensive battery bank is in danger. I would have to camp out at the site and monitor the charging over a day or so. I'm going to forward some of your comments and those of others that have generously offered suggestions and we'll see if I can convince the client who now believes everything is A-Ok. Best Regards, Ron Young earthRight Products - Solareagle.com Alternative Energy Solutions ~ Renewable Energy Products On 2011-10-22, at 12:06 PM, Larry Crutcher, Starlight Solar Power Systems wrote: Hi Ron, As many on this list have suggested, it sounds like a sulfated battery condition. In your last message you revealed something to me that absolutely confirms this but perhaps you didn't recognize it. Battery voltage readings are deceiving because they do not indicate capacity. 25.7 volts sounds like a fully charged 24 volt bank, but is it? Only if the battery was at rest for 5-6 hours could you have some confidence that the bank was full at this voltage. But this is not the case because the bank is in daily use, always charging or discharging. However, there is one useful indication that voltage can be used for: detecting a sulfated battery. You mentioned that the the battery drops to 24.5 in the early AM without any heavy loads on. For the 4KS25 battery this equates to about 800AH at the 72 hour rate. Then you said that the customer ran a 2500 watt generator for 5 minutes and drove the voltage up to 29 volts. Here's the Ah-Ha moment: That is EXACTLY the behavior of a heavily sulfated battery bank. A fast rise in voltage indicates sulfation. It is impossible for that tiny generator, or any charge source they own for that matter, to replace the hundreds of AH it would take to drive a healthy battery up to the absorb voltage of 29 volts. The bank is about 45,000 watt hours (72h rate). There would have to be over 20,000 Wh removed to be at that voltage. How many Wh's are replaced in 5 minutes by a 2500 watt genny? I'm sure you are getting the picture. Why did this happen to these expensive batteries? Glad you asked. Battery plates are not uniformly efficient in the electrochemical process leaving some portions with lead sulfate even after 8 hours of charging. Unless these portions are cleared off regularly by achieving 100% SoC and occasional, thorough equalization, the amorphous sulfate will convert to a crystalline form and grow. 99% charge, if not corrected in time, will always cause premature battery failure. Undersized RE charging systems, or perhaps oversized batteries, is the culprit that contributes to this all too frequent phenomenon of chronic undercharging. I say contribute because there are other factors. Fact: it can take 10-12 hours to fully charge a lead acid battery. Fact: The time element of battery charging is a highly misunderstood part. With only a few daily sun-hours to work with, how do we get a battery charged with PV solar? Properly sizing the PV array to the battery AND consumption is critical. One method I think is essential for nearly all PV systems is use a generator and charger, appropriately sized to the battery. By bulk charging early in the AM you can reduce the finish time to perhaps 5-6 hours of constant voltage charging, something easily done with a PV system. Ron, you might be able to recover some capacity in this bank if the sulfate has not formed hard crystals by now.
Re: [RE-wrenches] intermittent battery problem; ...Battery Sulfation
Ron, You have made a connection that I would not have made, and while I may be wrong here, it has got me thinking. I have never equated low water level with SG, nor have I ever read in battery maintenance guides that I should maintain a particular water level before measuring SG. I'm not convinced that electrolyte level has any connection with measured SG, although it would seem logical on the surface. I have always thought that if the correct concentration of acid was installed at the factory and not lost thereafter (such as due to a spill or chronic overfilling), the SC is only a function of SOC. I'm interested in others' opinions here. Allan Positive Energy On Mon, Oct 24, 2011 at 1:49 AM, Ron Young solarea...@solareagle.comwrote: Hi Larry, I immediately assumed sulphated battery when I heard the customers description a couple of weeks ago but the hydrometer readings didn't jive. Any sulphated battery I've encountered, and I defer to your greater experience, has always revealed itself with a simple S.G. test and these batteries were reading above 1.265. I then thought the possibility of a defective hydrometer and had them test with another but we just got confirmation of the same thing. The weird drop in voltage also isn't explained by your description. Why would this just happen without loads or charging present (except maybe the DC Sunfrost load) at the same predictable time at 4 a.m. The fact that when the generator was turned on and sent a surge of current into the system and the problem went away made the detective in me think there had to be another explanation. The bank was at rest for several hours through the night and the voltage dropout was cured by a brief application of charge current. When I arrived on site my discovery that the client was under watering the batteries and this chronic condition resulted in a very rich electrolyte, reading well above 1.265 - into the 1.280 range made me think that was the problem and it seems to have gone away now that the electrolyte level was raised and the batteries given a good charge. But it still nags at me that something else is lurking in the shadows. Your description of the sulphate converting to a crystalline form has me worried because if this is the case this expensive battery bank is in danger. I would have to camp out at the site and monitor the charging over a day or so. I'm going to forward some of your comments and those of others that have generously offered suggestions and we'll see if I can convince the client who now believes everything is A-Ok. Best Regards, *Ron Young* earthRight Products - Solareagle.com Alternative Energy Solutions ~ Renewable Energy Products On 2011-10-22, at 12:06 PM, Larry Crutcher, Starlight Solar Power Systems wrote: Hi Ron, As many on this list have suggested, it sounds like a sulfated battery condition. In your last message you revealed something to me that absolutely confirms this but perhaps you didn't recognize it. Battery voltage readings are deceiving because they do not indicate capacity. 25.7 volts sounds like a fully charged 24 volt bank, but is it? Only if the battery was at rest for 5-6 hours could you have some confidence that the bank was full at this voltage. But this is not the case because the bank is in daily use, always charging or discharging. However, there is one useful indication that voltage can be used for: detecting a sulfated battery. You mentioned that the the battery drops to 24.5 in the early AM without any heavy loads on. For the 4KS25 battery this equates to about 800AH at the 72 hour rate. Then you said that the customer ran a 2500 watt generator for 5 minutes and drove the voltage up to 29 volts. Here's the Ah-Ha moment: That is EXACTLY the behavior of a heavily sulfated battery bank. A fast rise in voltage indicates sulfation. It is impossible for that tiny generator, or any charge source they own for that matter, to replace the hundreds of AH it would take to drive a healthy battery up to the absorb voltage of 29 volts. The bank is about 45,000 watt hours (72h rate). There would have to be over 20,000 Wh removed to be at that voltage. How many Wh's are replaced in 5 minutes by a 2500 watt genny? I'm sure you are getting the picture. Why did this happen to these expensive batteries? Glad you asked. Battery plates are not uniformly efficient in the electrochemical process leaving some portions with lead sulfate even after 8 hours of charging. Unless these portions are cleared off regularly by achieving 100% SoC and occasional, thorough equalization, the amorphous sulfate will convert to a crystalline form and grow. 99% charge, if not corrected in time, will always cause premature battery failure. Undersized RE charging systems, or perhaps oversized batteries, is the culprit that contributes to this all too frequent phenomenon of chronic undercharging. I say contribute because there are other
Re: [RE-wrenches] intermittent battery problem; ...Battery Sulfation
Ron, Sorry to beat a dead horse, but a Pentametric will reveal what happens at 4am (or any other time). At a minimum all you need is the sending unit, 2-3 shunts and the serial converter. You then use your laptop to download and analyze what happened in the past few days, etc. of course, the display unit can show the customer details as well. The Pentametric can also monitor SOC and has a relay that can start the generator or turn on a Start the Genny Now indicator. As for sulfated batteries, I think SG will be higher with less water in the batteries for a given state of charge. That's just my gut talking not some advanced Molarity vs SG vs concentration calculation that I can vaguely remember doing. The bottom line, you still don't know if the customer will bounce another energy check since they are not keeping a check register to know the daily balance. Thank you, Maverick Maverick Brown BSEET, NABCEP Certified Solar PV Installer ® President CEO Maverick Solar Enterprises, Inc. Office: 512-919-4493 Cell:512-460-9825 Sent from an iPhone. On Oct 24, 2011, at 2:49 AM, Ron Young solarea...@solareagle.com wrote: Hi Larry, I immediately assumed sulphated battery when I heard the customers description a couple of weeks ago but the hydrometer readings didn't jive. Any sulphated battery I've encountered, and I defer to your greater experience, has always revealed itself with a simple S.G. test and these batteries were reading above 1.265. I then thought the possibility of a defective hydrometer and had them test with another but we just got confirmation of the same thing. The weird drop in voltage also isn't explained by your description. Why would this just happen without loads or charging present (except maybe the DC Sunfrost load) at the same predictable time at 4 a.m. The fact that when the generator was turned on and sent a surge of current into the system and the problem went away made the detective in me think there had to be another explanation. The bank was at rest for several hours through the night and the voltage dropout was cured by a brief application of charge current. When I arrived on site my discovery that the client was under watering the batteries and this chronic condition resulted in a very rich electrolyte, reading well above 1.265 - into the 1.280 range made me think that was the problem and it seems to have gone away now that the electrolyte level was raised and the batteries given a good charge. But it still nags at me that something else is lurking in the shadows. Your description of the sulphate converting to a crystalline form has me worried because if this is the case this expensive battery bank is in danger. I would have to camp out at the site and monitor the charging over a day or so. I'm going to forward some of your comments and those of others that have generously offered suggestions and we'll see if I can convince the client who now believes everything is A-Ok. Best Regards, Ron Young earthRight Products - Solareagle.com Alternative Energy Solutions ~ Renewable Energy Products On 2011-10-22, at 12:06 PM, Larry Crutcher, Starlight Solar Power Systems wrote: Hi Ron, As many on this list have suggested, it sounds like a sulfated battery condition. In your last message you revealed something to me that absolutely confirms this but perhaps you didn't recognize it. Battery voltage readings are deceiving because they do not indicate capacity. 25.7 volts sounds like a fully charged 24 volt bank, but is it? Only if the battery was at rest for 5-6 hours could you have some confidence that the bank was full at this voltage. But this is not the case because the bank is in daily use, always charging or discharging. However, there is one useful indication that voltage can be used for: detecting a sulfated battery. You mentioned that the the battery drops to 24.5 in the early AM without any heavy loads on. For the 4KS25 battery this equates to about 800AH at the 72 hour rate. Then you said that the customer ran a 2500 watt generator for 5 minutes and drove the voltage up to 29 volts. Here's the Ah-Ha moment: That is EXACTLY the behavior of a heavily sulfated battery bank. A fast rise in voltage indicates sulfation. It is impossible for that tiny generator, or any charge source they own for that matter, to replace the hundreds of AH it would take to drive a healthy battery up to the absorb voltage of 29 volts. The bank is about 45,000 watt hours (72h rate). There would have to be over 20,000 Wh removed to be at that voltage. How many Wh's are replaced in 5 minutes by a 2500 watt genny? I'm sure you are getting the picture. Why did this happen to these expensive batteries? Glad you asked. Battery plates are not uniformly efficient in the electrochemical process leaving some portions with lead sulfate even after 8 hours of
Re: [RE-wrenches] intermittent battery problem; ...Battery Sulfation
There are yet other issues to consider relative to specific gravity. #1: I believe temperature has been mentioned already, but merits revisiting: Specific gravity varies somewhat with the temperature of the electrolyte. Some of the more sophisticated measurement equipment takes temperature into account. Lower cost models don't. However, temperature can be included in your calculations by use of a simple thermometer to measure approximate battery temperature at the time the SG readings are taken, then factored into the readings. Cold batteries will yield higher SG readings than warm ones. #2: Another concern is stratification. Acid is more dense than water and thus sinks to the bottom of the battery. For more accurate readings, electrolyte must be stirred to thoroughly re-mix the solution *before* samples are taken for SG measurement. Given the construction of batteries, this is difficult (but not impossible) to do. Failing that, and using just an initial sample of electrolyte from the top of a cell, SG readings from the top may be lower than actual values. Jamie Surrette recommends adding distilled water to bring the electrolyte level up to the manufacturer's recommended level, then charging the battery to a point of light-to-moderate outgassing (with all precautions, of course) for a couple of hours. After the battery has rested for as long as possible (24 hours suggested), *then* take a SG reading. Hydrogen and oxygen get trapped in the electrolyte and will cause errors in any SG readings taken immediately after such a charging period. Since this is an off-grid home, one option might be to charge with the generator as late into the evening as possible, then take SG readings the next morning before any significant loads are applied. May be a Friday night/Saturday AM event if the owner works during the week. Dan --- On Mon, 10/24/11, Allan Sindelar al...@positiveenergysolar.com wrote: From: Allan Sindelar al...@positiveenergysolar.com Subject: Re: [RE-wrenches] intermittent battery problem; ...Battery Sulfation To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Monday, October 24, 2011, 5:35 AM Ron,You have made a connection that I would not have made, and while I may be wrong here, it has got me thinking. I have never equated low water level with SG, nor have I ever read in battery maintenance guides that I should maintain a particular water level before measuring SG. I'm not convinced that electrolyte level has any connection with measured SG, although it would seem logical on the surface. I have always thought that if the correct concentration of acid was installed at the factory and not lost thereafter (such as due to a spill or chronic overfilling), the SC is only a function of SOC. I'm interested in others' opinions here. AllanPositive Energy ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] intermittent battery problem; ...Battery Sulfation
Hi Ron,Accurate SG readings are not simple. Was temperature compensation properly employed? Have they been keeping a log book to identify changes? How accurate is the hydrometer? How skilled is the person taking the reading?Most of the Battery Wrench responses suggest equalization but I don't see from any of your posts that this has been done yet. I suggest this to be the next step and I recommend that you carefully watch voltage and current. This will tell you a lot. I use a Fluke ScopeMeter in the TrendPlot mode and track voltage and current over time. It provides a good visual understanding.In case others are using this forum to glean information, attached is a chart for illustration of the charge cycle. You should see a constant, somewhat linear rise in voltage until the constant voltage setting is reached. If you see a sudden rise: suspect sulfation. If you see a quick reduction in current: suspect sulfation. The current should drop to about 8-10 amps at the constant voltage towards the end of charge cycle. The health and DoD will determine the time this takes, expect many hours. Begin equalization. A couple other points: Is the MX absorb voltage at 29.6V? Did you program the MX controller for an extended absorb time (advanced menu, absorb time limits)? The default setting is poor for large batteries. I use 90 minutes minimum and 4 hours max. This can greatly reduce the possibility of undercharging the battery but it may use more water. The timer (ChgT) will determine how long it stays in absorb each day.Larry CrutcherStarlight Solar Power Systems On Oct 24, 2011, at 12:49 AM, Ron Young wrote:Hi Larry,I immediately assumed sulphated battery when I heard the customers description a couple of weeks ago but the hydrometer readings didn't jive. Any sulphated battery I've encountered, and I defer to your greater experience, has always revealed itself with a simple S.G. test and these batteries were reading above 1.265. I then thought the possibility of a defective hydrometer and had them test with another but we just got confirmation of the same thing.The weird drop in voltage also isn't explained by your description. Why would this just happen without loads or charging present (except maybe the DC Sunfrost load) at the same predictable time at 4 a.m. The fact that when the generator was turned on and sent a surge of current into the system and the problem went away made the detective in me think there had to be another explanation. The bank was at rest for several hours through the night and the voltage dropout was cured by a brief application of charge current.When I arrived on site my discovery that the client was under watering the batteries and this chronic condition resulted in a very rich electrolyte, reading well above 1.265 - into the 1.280 range made me think that was the problem and it seems to have gone away now that the electrolyte level was raised and the batteries given a good charge. But it still nags at me that something else is lurking in the shadows. Your description of the sulphate converting to a crystalline form has me worried because if this is the case this expensive battery bank is in danger. I would have to camp out at the site and monitor the charging over a day or so. I'm going to forward some of your comments and those of others that have generously offered suggestions and we'll see if I can convince the client who now believes everything is A-Ok.Best Regards,Ron YoungearthRight Products - Solareagle.comAlternative Energy Solutions ~ Renewable Energy Products___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] intermittent battery problem; ...Battery Sulfation
Thanks Larry, this is one of the best explanations I have seen. I am saving it for my customers and students. I would emphasize the C/20 (as you said) or a little less for perhaps C/30 for this long term equalize or desulfation. Too fast an equaliziation can loosen (blow the plate material off the plates) . (I built a 60 hZ desulfator and have used it twice in 40 years, it seems to work) Thanks again great piece of writing and explanation, everyone should read Darryl From: Larry Crutcher, Starlight Solar Power Systems la...@starlightsolar.com To: RE-wrenches re-wrenches@lists.re-wrenches.org Sent: Saturday, October 22, 2011 2:06 PM Subject: Re: [RE-wrenches] intermittent battery problem; ...Battery Sulfation Hi Ron, As many on this list have suggested, it sounds like a sulfated battery condition. In your last message you revealed something to me that absolutely confirms this but perhaps you didn't recognize it. Battery voltage readings are deceiving because they do not indicate capacity. 25.7 volts sounds like a fully charged 24 volt bank, but is it? Only if the battery was at rest for 5-6 hours could you have some confidence that the bank was full at this voltage. But this is not the case because the bank is in daily use, always charging or discharging. However, there is one useful indication that voltage can be used for: detecting a sulfated battery. You mentioned that the the battery drops to 24.5 in the early AM without any heavy loads on. For the 4KS25 battery this equates to about 800AH at the 72 hour rate. Then you said that the customer ran a 2500 watt generator for 5 minutes and drove the voltage up to 29 volts. Here's the Ah-Ha moment: That is EXACTLY the behavior of a heavily sulfated battery bank. A fast rise in voltage indicates sulfation. It is impossible for that tiny generator, or any charge source they own for that matter, to replace the hundreds of AH it would take to drive a healthy battery up to the absorb voltage of 29 volts. The bank is about 45,000 watt hours (72h rate). There would have to be over 20,000 Wh removed to be at that voltage. How many Wh's are replaced in 5 minutes by a 2500 watt genny? I'm sure you are getting the picture. Why did this happen to these expensive batteries? Glad you asked. Battery plates are not uniformly efficient in the electrochemical process leaving some portions with lead sulfate even after 8 hours of charging. Unless these portions are cleared off regularly by achieving 100% SoC and occasional, thorough equalization, the amorphous sulfate will convert to a crystalline form and grow. 99% charge, if not corrected in time, will always cause premature battery failure. Undersized RE charging systems, or perhaps oversized batteries, is the culprit that contributes to this all too frequent phenomenon of chronic undercharging. I say contribute because there are other factors. Fact: it can take 10-12 hours to fully charge a lead acid battery. Fact: The time element of battery charging is a highly misunderstood part. With only a few daily sun-hours to work with, how do we get a battery charged with PV solar? Properly sizing the PV array to the battery AND consumption is critical. One method I think is essential for nearly all PV systems is use a generator and charger, appropriately sized to the battery. By bulk charging early in the AM you can reduce the finish time to perhaps 5-6 hours of constant voltage charging, something easily done with a PV system. Ron, you might be able to recover some capacity in this bank if the sulfate has not formed hard crystals by now. You can try a very long charge time, up to 24 hours, at high voltage, about 31 volts. You will need a larger generator. Monitor the temperature and reduce current if they get up to 125F internal. In our shop I have recovered sulfated batteries with high voltage charging, as much as 3Vpc (do not do this with any loads connected), at reduced current, about C*.05, and a 1 kHz pulser that I built. My findings over the years is the current will begin to rise very slowly, peak then drop if the recovery is working. Sorry that this post is getting so long. There's just so much. OK, one last thing. In my last post to you I recommended a battery AH monitor. This problem could have been detected and perhaps prevented if they had one. Larry Crutcher Starlight Solar Power Systems On Oct 21, 2011, at 11:39 AM, Ron Young wrote: Hi Maverick everyone, I visited the site a couple of days ago and load tested the batteries, checked individual voltages in the string of six Surrette 4KS25's (4.3v each), checked all connections etc. The client told me that when they would go to bed battery volts read 25.7. Through the night this would seem to stay steady. About 4 a.m. as far as they could tell the voltage would drop to about 24.5. This happened without a load present and with no charging present (calm
Re: [RE-wrenches] intermittent battery problem; ...Battery Sulfation
Thank you Darryl. The important thing is internal temperature. Any current up to the manufacturers specification can be used but C/20 means I usually don't need to baby sit the battery temp during long term recovery attempts. Adjust accordingly. One thing I didn't mention is that it's not harmful to deficit charge a battery for a few days or perhaps a couple weeks as long as the battery gets a 100% charge within that time frame. This may require more frequent equalization. Larry On Oct 23, 2011, at 6:22 AM, Darryl Thayer wrote: Thanks Larry, this is one of the best explanations I have seen. I am saving it for my customers and students. I would emphasize the C/20 (as you said) or a little less for perhaps C/30 for this long term equalize or desulfation. Too fast an equaliziation can loosen (blow the plate material off the plates) . (I built a 60 hZ desulfator and have used it twice in 40 years, it seems to work) Thanks again great piece of writing and explanation, everyone should read Darryl From: Larry Crutcher, Starlight Solar Power Systems la...@starlightsolar.com To: RE-wrenches re-wrenches@lists.re-wrenches.org Sent: Saturday, October 22, 2011 2:06 PM Subject: Re: [RE-wrenches] intermittent battery problem; ...Battery Sulfation Hi Ron, As many on this list have suggested, it sounds like a sulfated battery condition. In your last message you revealed something to me that absolutely confirms this but perhaps you didn't recognize it. Battery voltage readings are deceiving because they do not indicate capacity. 25.7 volts sounds like a fully charged 24 volt bank, but is it? Only if the battery was at rest for 5-6 hours could you have some confidence that the bank was full at this voltage. But this is not the case because the bank is in daily use, always charging or discharging. However, there is one useful indication that voltage can be used for: detecting a sulfated battery. You mentioned that the the battery drops to 24.5 in the early AM without any heavy loads on. For the 4KS25 battery this equates to about 800AH at the 72 hour rate. Then you said that the customer ran a 2500 watt generator for 5 minutes and drove the voltage up to 29 volts. Here's the Ah-Ha moment: That is EXACTLY the behavior of a heavily sulfated battery bank. A fast rise in voltage indicates sulfation. It is impossible for that tiny generator, or any charge source they own for that matter, to replace the hundreds of AH it would take to drive a healthy battery up to the absorb voltage of 29 volts. The bank is about 45,000 watt hours (72h rate). There would have to be over 20,000 Wh removed to be at that voltage. How many Wh's are replaced in 5 minutes by a 2500 watt genny? I'm sure you are getting the picture. Why did this happen to these expensive batteries? Glad you asked. Battery plates are not uniformly efficient in the electrochemical process leaving some portions with lead sulfate even after 8 hours of charging. Unless these portions are cleared off regularly by achieving 100% SoC and occasional, thorough equalization, the amorphous sulfate will convert to a crystalline form and grow. 99% charge, if not corrected in time, will always cause premature battery failure. Undersized RE charging systems, or perhaps oversized batteries, is the culprit that contributes to this all too frequent phenomenon of chronic undercharging. I say contribute because there are other factors. Fact: it can take 10-12 hours to fully charge a lead acid battery. Fact: The time element of battery charging is a highly misunderstood part. With only a few daily sun-hours to work with, how do we get a battery charged with PV solar? Properly sizing the PV array to the battery AND consumption is critical. One method I think is essential for nearly all PV systems is use a generator and charger, appropriately sized to the battery. By bulk charging early in the AM you can reduce the finish time to perhaps 5-6 hours of constant voltage charging, something easily done with a PV system. Ron, you might be able to recover some capacity in this bank if the sulfate has not formed hard crystals by now. You can try a very long charge time, up to 24 hours, at high voltage, about 31 volts. You will need a larger generator. Monitor the temperature and reduce current if they get up to 125F internal. In our shop I have recovered sulfated batteries with high voltage charging, as much as 3Vpc (do not do this with any loads connected), at reduced current, about C*.05, and a 1 kHz pulser that I built. My findings over the years is the current will begin to rise very slowly, peak then drop if the recovery is working. Sorry that this post is getting so long. There's just so much. OK, one last thing. In my last post to you I recommended a battery AH monitor. This problem could have been detected and perhaps prevented if they had one
Re: [RE-wrenches] intermittent battery problem; ...Battery Sulfation
Hi Ron, As many on this list have suggested, it sounds like a sulfated battery condition. In your last message you revealed something to me that absolutely confirms this but perhaps you didn't recognize it. Battery voltage readings are deceiving because they do not indicate capacity. 25.7 volts sounds like a fully charged 24 volt bank, but is it? Only if the battery was at rest for 5-6 hours could you have some confidence that the bank was full at this voltage. But this is not the case because the bank is in daily use, always charging or discharging. However, there is one useful indication that voltage can be used for: detecting a sulfated battery. You mentioned that the the battery drops to 24.5 in the early AM without any heavy loads on. For the 4KS25 battery this equates to about 800AH at the 72 hour rate. Then you said that the customer ran a 2500 watt generator for 5 minutes and drove the voltage up to 29 volts. Here's the Ah-Ha moment: That is EXACTLY the behavior of a heavily sulfated battery bank. A fast rise in voltage indicates sulfation. It is impossible for that tiny generator, or any charge source they own for that matter, to replace the hundreds of AH it would take to drive a healthy battery up to the absorb voltage of 29 volts. The bank is about 45,000 watt hours (72h rate). There would have to be over 20,000 Wh removed to be at that voltage. How many Wh's are replaced in 5 minutes by a 2500 watt genny? I'm sure you are getting the picture. Why did this happen to these expensive batteries? Glad you asked. Battery plates are not uniformly efficient in the electrochemical process leaving some portions with lead sulfate even after 8 hours of charging. Unless these portions are cleared off regularly by achieving 100% SoC and occasional, thorough equalization, the amorphous sulfate will convert to a crystalline form and grow. 99% charge, if not corrected in time, will always cause premature battery failure. Undersized RE charging systems, or perhaps oversized batteries, is the culprit that contributes to this all too frequent phenomenon of chronic undercharging. I say contribute because there are other factors. Fact: it can take 10-12 hours to fully charge a lead acid battery. Fact: The time element of battery charging is a highly misunderstood part. With only a few daily sun-hours to work with, how do we get a battery charged with PV solar? Properly sizing the PV array to the battery AND consumption is critical. One method I think is essential for nearly all PV systems is use a generator and charger, appropriately sized to the battery. By bulk charging early in the AM you can reduce the finish time to perhaps 5-6 hours of constant voltage charging, something easily done with a PV system. Ron, you might be able to recover some capacity in this bank if the sulfate has not formed hard crystals by now. You can try a very long charge time, up to 24 hours, at high voltage, about 31 volts. You will need a larger generator. Monitor the temperature and reduce current if they get up to 125F internal. In our shop I have recovered sulfated batteries with high voltage charging, as much as 3Vpc (do not do this with any loads connected), at reduced current, about C*.05, and a 1 kHz pulser that I built. My findings over the years is the current will begin to rise very slowly, peak then drop if the recovery is working. Sorry that this post is getting so long. There's just so much. OK, one last thing. In my last post to you I recommended a battery AH monitor. This problem could have been detected and perhaps prevented if they had one. Larry Crutcher Starlight Solar Power Systems On Oct 21, 2011, at 11:39 AM, Ron Young wrote: Hi Maverick everyone, I visited the site a couple of days ago and load tested the batteries, checked individual voltages in the string of six Surrette 4KS25's (4.3v each), checked all connections etc. The client told me that when they would go to bed battery volts read 25.7. Through the night this would seem to stay steady. About 4 a.m. as far as they could tell the voltage would drop to about 24.5. This happened without a load present and with no charging present (calm, no wind, no sun). They would start up the generator for five minutes in the morning and see the voltage come up to just above 29v then turn off the generator (a small Honda 2500) and the voltage would settly at 25.7 and remain there most of the day even when using their light loads, some lights, phone system, laptop and the Sunfrost. When checking the batteries I noticed they needed watering and mentioned this to the customer. The electrolyte was just over the plastic screen above the plates by about 1/4 inch. He said he had just watered them and always kept them filled. I replied that they were low and when he looked he said no, that's where I keep them! When I checked the specific gravity reading it was very rich reading
