Hey Jon, I know this is coming from a Trojan competitor... but in the interest in attempting to help...
The battery bank sounds severely sulfated to me... The settings that he had originally programmed are going to contribute to this. Unfortunately by setting the Bulk/Absorb to 28.8, not only is going to contribute to this but it's going to accelerate the sulfation issues. I would suggest getting the voltages up to 29.6 or maybe 29.8 until recovery. Are you aware that most battery manufactures including trojan have raised their recommendations on Bulk/Absorb Voltage over the past 5-6 years? Not sure about the Model number that he's using but the L16's tend to be around 29.6 Volts Temp compensated at 25C or 77F... I'm also assuming 2000 ah of capacity... This means that if you are using the Battery Temp Sensors you set the Bulk/Absorb Voltage at 29.6, and the Temps compensation to 5mv and let the charger do the temp compensation. Here is how I would program the controllers. Array 1 South Facing 4-Canadian 250w (one string) This array is only 1000 Watts... At the peak in perfect conditions, you are only going to see a max output of between 40 and 45 amps of current. Flexmax 80 Absorb 29.3V 6hrs *29.6 (29.8) 8 Hours.* Float 27.3 *27.3* End Amps 10A * 0 (Typically I'd set for 4-6, but End Amps can trigger to easily on a sulfated bank so it should be defeated or 0)* Rebulk 25V *Solar Array is too Small Re-Bulk Voltage will never trigger because the controller really should never be in float. * Array 2 South Facing 6-205w 2-195w (one string) This array is only 1620 Watts... At the peak in perfect conditions, you are only going to see a max output of between 60-70 amps of current, but with the module mismatch, this will be closer to 50-55 amps of current. Flexmax 60 Absorb 29.3V 6hrs * 29.6 (29.8)* *8 Hours. * Float 27.3 * 27.3* End Amps 10A * 0 (Typically I'd set for 4-6 Hours, but End Amps can trigger to easily on a sulfated bank so it should be defeated or 0) * Rebulk 25.6V * Same As Above.. * For Flooded Lead-acid batteries when you finish the Bulk Stage of charging (Voltage gets to 29.6 Volts) the battery bank is only about 80% SOC. In Bulk, you are about 90-100 of peak current going into the battery. When Absorb starts current starts to drop off typically up to 60% during the entire absorb stage... It's tough to calculate this, at rolls we have the formula to do this which is: .42 X C/20 Rate / Nominal Current. Since these two arrays are pointing the same general direction I would have added the currents of these together and derated them 60-70%... The best thing to do is to take a couple of meter readings when the battery bank is new and adjust absorb time-based on actual SG readings. So in this case peak currents together are going to be around: Array 1 40 amps Array 2 60 amps (limited by the controller) 100 amp total current... So: .42 X 2000 ah / 60a (70) = 12 to 14 Hours! We are all aware that this array alone it'll take two full days of the summer sun to get to 100%... Array 3 North Facing 8-295w Renosola (4 strings) Flexmax 80 Absorb 29.4 1hr *29.6 (29.8) - 8 Hr. * Float 27.3 *27.3* End Amps 0 *Same Advice as above..*. Rebulk 24 *Same As Above. * Using the same principles on this array, that I did the last... .42 X 2000 / 70 amps = 12 Hours.. These arrays are sized way too small! There isn't much reason to set the Absrob Time much past 8 hours. Lastly, I'm assuming you're getting your SOC information from the Flexnet DC... Those Settings should be as follows.. End Amps or Return Amps = 30-40 Parameters Met Voltage 29.4 (Typically .2vdc under Target Voltage for 24 Volt Systems) Parameters Met Time = 1 Hour. BCF% = 80% (For Flooded, regardless of who makes them this should be 80% to start, after three years you should lower by 1% per year because as batteries age, they become less efficient. In any case, due to the undersized nature of the arrays, I would advise that you have the customer start the generator about 4-5 days a week before the sun hits the panels... when the sun hits the panels, you shut the generator off, and let the solar do the absorb charge. As the battery bank starts to get closer to 1.265+ in Specific Gravity's then you can start to back off the number of times you need to start but the fact is this battery bank is way to large for this array to handle. They should be starting the genny at least one day a week to get any FLA battery to full at least once a week. Good luck, and if you have any further questions I'll do what I can to help... <http://www.rollsbattery.com> <http://www.rollsbattery.com> <http://www.rollsbattery.com> <http://www.rollsbattery.com> <http://www.rollsbattery.com> <http://www.rollsbattery.com> <http://www.rollsbattery.com> <http://www.rollsbattery.com> <http://www.rollsbattery.com> <http://www.rollsbattery.com> <http://www.rollsbattery.com> <http://www.rollsbattery.com> <http://www.rollsbattery.com> <http://www.rollsbattery.com> <http://www.rollsbattery.com> <http://www.rollsbattery.com> Steve Higgins ⋅ Technical Services Manager t +1.902.597.4020 m +1.206.790.5840 f +1.902.597.8447 e [email protected] <#SignatureSanitizer_SafeHtmlFilter_> <http://www.facebook.com/RollsBattery> <http://www.facebook.com/RollsBattery> <http://www.twitter.com/RollsBattery> <https://www.youtube.com/user/RollsBattery> <https://www.linkedin.com/company/rolls-battery-engineering> <http://www.instagram.com/RollsBattery> <http://www.instagram.com/RollsBattery> <http://www.instagram.com/RollsBattery> ------------------------------ *Become a Certified PV Professional. Register for* *NABCEP CEC 2020* <http://rollsbattery.com/nabcep2020> *using promo code* *20RBE* <http://rollsbattery.com/nabcep2020> ------------------------------ CONFIDENTIALITY: The information transmitted herein is intended only for the addressee and may contain confidential, proprietary and/or privileged material. Any unauthorized review, distribution or other use of or the taking of any action in reliance upon this information is prohibited. If you receive this email in error, please contact the sender and delete or destroy this message and all copies. ------------------------------ On Tue, Feb 18, 2020 at 8:37 PM Jon Siegenthaler <[email protected]> wrote: > Hey Wrenches, > > I just did a site visit for a client who's had a few iterations of PV > installed. The main reason for the call was that the battery bank would > never charge to 100%SOC but rather appear to charge to 100%SOC and actually > hover around 70%SOC. At the end of the day the client would top it off > with the generator for 30-60min. This has been happening since October, I > just got the call the other day. > > The site is less than code compliant to say the least and the programming > of the 3 charge controllers were not equal. > > Array 1 South Facing 4-Canadian 250w (one string) > Flexmax 80 > Absorb 29.3V 6hrs > Float 27.3 > End Amps 10A > Rebulk 25V > > Array 2 South Facing 6-205w 2-195w (one string) > Flexmax 60 > Absorb 29.3V 6hrs > Float 27.3 > End Amps 10A > Rebulk 25.6V > > Array 3 North Facing 8-295w Renosola (4 strings) > Flexmax 80 > Absorb 29.4 1hr > Float 27.3 > End Amps 0 > Rebulk 24 > > 20-Trojan Reliant L16 12V (5 parallel to a bus) purchased the end of 2017 > > Apart from the not so great design to say it lightly, the bank is > consistently showing a stepping voltage of about 70%SOC up to 100%SOC from > negative to positive. I changed the charge controllers to an equal > absorption voltage and time (28.8V and 4hrs) to try and slowly bring up the > lagging side of the bank. I was cautious not to raise them all to 29.4 at > 4+hrs because I don't know their history and didn't want to cook them > further if they are indeed headed that way. At the time of inspection the > batteries were about 84F and the thermal camera showed no variations or hot > spots. > > I asked the owner to report back if it gets better, worse, or the same. He > reported back and said that the total kWh production daily is gradually > going down over these past few days. Any suggestions on how to bring this > bank back to 100%SOC would be appreciated. > > Jon Siegenthaler > _______________________________________________ > List sponsored by Redwood Alliance > > List Address: [email protected] > > Change listserver email address & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > List-Archive: > http://www.mail-archive.com/[email protected]/maillist.html > > List rules & etiquette: > www.re-wrenches.org/etiquette.htm > > Check out or update participant bios: > www.members.re-wrenches.org > >
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