Re: [RE-wrenches] Battery Bank to Inverter Wiring
This is a good representation of poor battery design. Reducing the # of strings by increasing the capacity of the battery should always be considered. Yes this is a cheap way to go but in the long run this type of install can be very expensive. Without someone as experienced as Jarmo, the installer may never have figured this out. LESS STRINGS more Ahours = less interconnects potential for inductance and gives one far better performance charging discharging. One bad cell and one is chasing their tail for quite a while w/ this install. On Jun 29, 2015, at 6:28 PM, jarmo.venalai...@schneider-electric.com wrote: Hi: I'm not sure how much trouble this has caused, so that's why I asked the question. With large battery banks, it is possible to end up with a cabling layout which has a potentially very large loop area as was the case at one of the sites where I saw problems. Here's a picture of the battery bank they had created. Mail Attachment.gif The + and - cables were not run side by side and the rack is made out of steel. The inverters did not like it until we ran the cables along the battery bank and then side by side. Once that was done, things worked as expected. JARMO _ Jarmo Venalainen | Schneider Electric | Xantrex Brand | CANADA | Sales Application Engineer Phone: +604-422-2528 | Tech Support: 800-670-0707 | Mobile: +604-505-0291 Email: jarmo.venalai...@schneider-electric.com | Site: www.Xantrex.com | Address: 3700 Gilmore Way, Burnaby, BC V5G4M1 Mail Attachment.gif Mail Attachment.gif Mail Attachment.gif Mail Attachment.gif Mail Attachment.gif *** Please consider the environment before printing this e-mail From: Ray Walters r...@solarray.com To: RE-wrenches re-wrenches@lists.re-wrenches.org, Date: 06/29/2015 03:05 PM Subject: Re: [RE-wrenches] Battery Bank to Inverter Wiring Sent by: RE-wrenches re-wrenches-boun...@lists.re-wrenches.org This is fascinating because while I knew the DC cables had an AC component, I never realized how much inductance played in the volt drop to the inverter. Thanks for bringing this to our attention Jarmo. Which brings up another question based on Benn's question: isn't the battery itself part of the inductive loop? and would the lead inside and steel cases act to increase the inductance? Should we consider changing battery layouts not just to shorten cable lengths, but to counter inductance in the batteries themselves? If needed, we could actually wire the batteries to twist by putting every other 2 v cell in the opposite row. My guess is that it wouldn't be worth it, but I've been wrong many times... R.Ray Walters CTO, Solarray, Inc Nabcep Certified PV Installer, Licensed Master Electrician Solar Design Engineer 303 505-8760 On 6/29/2015 3:55 PM, Benn Kilburn wrote: What about when you have the (+) and (-) terminals at opposite ends of a larger battery bank? Sure you can run the conductors side-by-side once they meet up on their way to the inverter, but would you consider the distance between the end terminals a large loop? Ideally the battery string is laid out so the end terminals are close together and close to the inverter, but this isn't always the case. Benn Kilburn SkyFire Energy Inc. 780-906-7807 On Jun 29, 2015, at 10:28 AM, jarmo.venalai...@schneider-electric.com wrote: Hi: From the comments so far, it appears that within the wrenches group, good practices are the rule and DC cables are kept side by side, so the problem I mentioned hasn't come up much. I have seen large loop battery cables a couple of times in solar installs myself out on islands way down south. Also on boats/RV's/motor homes. Please keep the cable loop in mind when you do bench tests of inverters, as it may screw up the results and make it seem like there is something wrong with the inverter. JARMO _ Jarmo Venalainen | Schneider Electric | Xantrex Brand | CANADA | Sales Application Engineer Phone: +604-422-2528 | Tech Support: 800-670-0707 | Mobile: +604-505-0291 Email: jarmo.venalai...@schneider-electric.com | Site: www.Xantrex.com | Address: 3700 Gilmore Way, Burnaby, BC V5G4M1 mime-attachment.gif mime-attachment.gif mime-attachment.gif mime-attachment.gif mime-attachment.gif *** Please consider the environment before printing this e-mail From: b...@midnitesolar.com b...@midnitesolar.com To: RE-wrenches re-wrenches@lists.re-wrenches.org, Date: 06/28/2015 10:30 PM Subject: Re: [RE-wrenches] Battery Bank to Inverter Wiring Sent by: RE-wrenches re-wrenches-boun...@lists.re-wrenches.org
Re: [RE-wrenches] Battery Bank to Inverter Wiring
mailto:jarmo.venalai...@schneider-electric.com | *Site:*_www.Xantrex.com_ http://www.xantrex.com/ | *Address:* 3700 Gilmore Way, Burnaby, BC V5G4M1 mime-attachment.gif http://www.xantrexrebate.com/ mime-attachment.gif http://www.xantrex.com/ mime-attachment.gif https://www.facebook.com/Xantrex mime-attachment.gif https://twitter.com/Xantrex mime-attachment.gif https://twitter.com/Xantrex *** Please consider the environment before printing this e-mail From: b...@midnitesolar.com mailto:b...@midnitesolar.com b...@midnitesolar.com mailto:b...@midnitesolar.com To: RE-wrenches re-wrenches@lists.re-wrenches.org mailto:re-wrenches@lists.re-wrenches.org, Date: 06/28/2015 10:30 PM Subject:Re: [RE-wrenches] Battery Bank to Inverter Wiring Sent by:RE-wrenches re-wrenches-boun...@lists.re-wrenches.org mailto:re-wrenches-boun...@lists.re-wrenches.org On 6/28/2015 9:20 AM, Allan Sindelar wrote: I'm not an EE, but I can't see what difference twisting would make in the absence of a building/collapsing field as is normal with AC. It is little known that with the typical inverters that use the heavy power transformers, have a lot of AC 120 Hz (or 100 Hz for 50 Hz systems) current mixed in with that DC battery current. The AC output current reflects back to the input as ripple current. This is why you want to have at least short as possible Sbattery cable runs AND keep the wires as close together as possible. Twisting the battery cables may help a bit but that is probably overkill. The problem has to do with inductance in the battery cables. You can use as big of cable as you can fit in to reduce resistance, but that will not help to lower the inductance. The problems you can sometimes have with high inductance is that L-C resonance at the inverter can raise the peak voltages seen at the inverter input terminals and can be hard on the inverter. Then again, the high frequency, lighter weight inverters will typically keep most of that ripple inside, between the DC input and AC output and battery cable inductance will not be as much of a problem on the battery cables. boB Gudgel On 6/28/2015 9:20 AM, Allan Sindelar wrote: As a matter of course I have always run the positive and negative conductors of high-current cable pairs together, but have never deliberately twisted them, and have never known of any related problems. The most obvious example of this would be 4/0 battery/inverter cables in a 24V system, with a 250A GJ-class breaker or (prior to that) a 300A or 400A Class T fuse. It's pretty tough to thread a twisted pair of 4/0 USE/RHH/RHW cables through a 2 elbow or LB from inverter enclosure to battery enclosure. I'm not an EE, but I can't see what difference twisting would make in the absence of a building/collapsing field as is normal with AC. I have twisted AC conductors together in the past when clients have expressed concerns about EMF from their equipment and wiring, but only AC. Allan *Allan Sindelar*_ __allan@sindelarsolar.com_ mailto:al...@sindelarsolar.com NABCEP Certified PV Installation Professional NABCEP Certified Technical Sales Professional New Mexico EE98J Journeyman Electrician Founder (Retired), Positive Energy, Inc.* 505 780-2738 tel:505%20780-2738 cell* On 6/27/2015 2:40 AM, John wrote: That is why for years we have been twisting those leads around each other. I was told it was to cancel out the opposing fields on the wires, but for whatever the correct technical reason is, we have always twisted those heavy wires. John V. *From:* RE-wrenches [_mailto:re-wrenches-boun...@lists.re-wrenches.org_] *On Behalf Of *_Jarmo.Venalainen@schneider-electric.com_ mailto:jarmo.venalai...@schneider-electric.com* Sent:* Saturday, 27 June 2015 5:45 a.m.* To:* RE-wrenches* Subject:* [RE-wrenches] Battery Bank to Inverter Wiring Hi: From time to time over the years I've come across systems where the routing of DC cables between the batteries and the inverter has been the cause of issues. I'm not referring to wire thickness or quality of terminations. For the purposes of this discussion, just assume that wire thickness and terminations are perfect. What I am referring to is the routing of the positive and negative battery cables. In particular, the loop area within the + and - cables as shown in the image below, The problem I've seen in systems with a large loop in the setup is that the inverter does not provide good surge power and can even go into low voltage shutdown during large surges. Recently
Re: [RE-wrenches] Battery Bank to Inverter Wiring
What about when you have the (+) and (-) terminals at opposite ends of a larger battery bank? Sure you can run the conductors side-by-side once they meet up on their way to the inverter, but would you consider the distance between the end terminals a large loop? Ideally the battery string is laid out so the end terminals are close together and close to the inverter, but this isn't always the case. Benn Kilburn SkyFire Energy Inc. 780-906-7807 On Jun 29, 2015, at 10:28 AM, jarmo.venalai...@schneider-electric.com wrote: Hi: From the comments so far, it appears that within the wrenches group, good practices are the rule and DC cables are kept side by side, so the problem I mentioned hasn't come up much. I have seen large loop battery cables a couple of times in solar installs myself out on islands way down south. Also on boats/RV's/motor homes. Please keep the cable loop in mind when you do bench tests of inverters, as it may screw up the results and make it seem like there is something wrong with the inverter. JARMO _ Jarmo Venalainen | Schneider Electric | Xantrex Brand | CANADA | Sales Application Engineer Phone: +604-422-2528 | Tech Support: 800-670-0707 | Mobile: +604-505-0291 Email: jarmo.venalai...@schneider-electric.com | Site: www.Xantrex.com | Address: 3700 Gilmore Way, Burnaby, BC V5G4M1 mime-attachment.gif mime-attachment.gif mime-attachment.gif mime-attachment.gif mime-attachment.gif *** Please consider the environment before printing this e-mail From: b...@midnitesolar.com b...@midnitesolar.com To: RE-wrenches re-wrenches@lists.re-wrenches.org, Date: 06/28/2015 10:30 PM Subject: Re: [RE-wrenches] Battery Bank to Inverter Wiring Sent by: RE-wrenches re-wrenches-boun...@lists.re-wrenches.org On 6/28/2015 9:20 AM, Allan Sindelar wrote: I'm not an EE, but I can't see what difference twisting would make in the absence of a building/collapsing field as is normal with AC. It is little known that with the typical inverters that use the heavy power transformers, have a lot of AC 120 Hz (or 100 Hz for 50 Hz systems) current mixed in with that DC battery current. The AC output current reflects back to the input as ripple current. This is why you want to have at least short as possible Sbattery cable runs AND keep the wires as close together as possible. Twisting the battery cables may help a bit but that is probably overkill. The problem has to do with inductance in the battery cables. You can use as big of cable as you can fit in to reduce resistance, but that will not help to lower the inductance. The problems you can sometimes have with high inductance is that L-C resonance at the inverter can raise the peak voltages seen at the inverter input terminals and can be hard on the inverter. Then again, the high frequency, lighter weight inverters will typically keep most of that ripple inside, between the DC input and AC output and battery cable inductance will not be as much of a problem on the battery cables. boB Gudgel On 6/28/2015 9:20 AM, Allan Sindelar wrote: As a matter of course I have always run the positive and negative conductors of high-current cable pairs together, but have never deliberately twisted them, and have never known of any related problems. The most obvious example of this would be 4/0 battery/inverter cables in a 24V system, with a 250A GJ-class breaker or (prior to that) a 300A or 400A Class T fuse. It's pretty tough to thread a twisted pair of 4/0 USE/RHH/RHW cables through a 2 elbow or LB from inverter enclosure to battery enclosure. I'm not an EE, but I can't see what difference twisting would make in the absence of a building/collapsing field as is normal with AC. I have twisted AC conductors together in the past when clients have expressed concerns about EMF from their equipment and wiring, but only AC. Allan Allan Sindelar al...@sindelarsolar.com NABCEP Certified PV Installation Professional NABCEP Certified Technical Sales Professional New Mexico EE98J Journeyman Electrician Founder (Retired), Positive Energy, Inc. 505 780-2738 cell On 6/27/2015 2:40 AM, John wrote: That is why for years we have been twisting those leads around each other. I was told it was to cancel out the opposing fields on the wires, but for whatever the correct technical reason is, we have always twisted those heavy wires. John V. From: RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of jarmo.venalai...@schneider-electric.com Sent: Saturday, 27 June 2015 5:45 a.m. To: RE-wrenches Subject: [RE-wrenches] Battery Bank to Inverter Wiring Hi: From time to time over the years I've come across systems where the routing of DC cables
Re: [RE-wrenches] Battery Bank to Inverter Wiring
This is fascinating because while I knew the DC cables had an AC component, I never realized how much inductance played in the volt drop to the inverter. Thanks for bringing this to our attention Jarmo. Which brings up another question based on Benn's question: isn't the battery itself part of the inductive loop? and would the lead inside and steel cases act to increase the inductance? Should we consider changing battery layouts not just to shorten cable lengths, but to counter inductance in the batteries themselves? If needed, we could actually wire the batteries to twist by putting every other 2 v cell in the opposite row. My guess is that it wouldn't be worth it, but I've been wrong many times... R.Ray Walters CTO, Solarray, Inc Nabcep Certified PV Installer, Licensed Master Electrician Solar Design Engineer 303 505-8760 On 6/29/2015 3:55 PM, Benn Kilburn wrote: What about when you have the (+) and (-) terminals at opposite ends of a larger battery bank? Sure you can run the conductors side-by-side once they meet up on their way to the inverter, but would you consider the distance between the end terminals a large loop? Ideally the battery string is laid out so the end terminals are close together and close to the inverter, but this isn't always the case. Benn Kilburn SkyFire Energy Inc. 780-906-7807 On Jun 29, 2015, at 10:28 AM, jarmo.venalai...@schneider-electric.com mailto:jarmo.venalai...@schneider-electric.com wrote: Hi: From the comments so far, it appears that within the wrenches group, good practices are the rule and DC cables are kept side by side, so the problem I mentioned hasn't come up much. I have seen large loop battery cables a couple of times in solar installs myself out on islands way down south. Also on boats/RV's/motor homes. Please keep the cable loop in mind when you do bench tests of inverters, as it may screw up the results and make it seem like there is something wrong with the inverter. JARMO _ * Jarmo Venalainen* | *Schneider Electric **| Xantrex Brand* | *CANADA* | *Sales Application Engineer* * Phone:* +604-422-2528 | *Tech Support:* 800-670-0707 | *Mobile:* +604-505-0291 * Email:* _jarmo.venalainen@schneider-electric.com_ mailto:jarmo.venalai...@schneider-electric.com | *Site:*_www.Xantrex.com_ http://www.xantrex.com/ | *Address:* 3700 Gilmore Way, Burnaby, BC V5G4M1 mime-attachment.gif http://www.xantrexrebate.com/ mime-attachment.gif http://www.xantrex.com/ mime-attachment.gif https://www.facebook.com/Xantrex mime-attachment.gif https://twitter.com/Xantrex mime-attachment.gif https://twitter.com/Xantrex *** Please consider the environment before printing this e-mail From: b...@midnitesolar.com mailto:b...@midnitesolar.com b...@midnitesolar.com mailto:b...@midnitesolar.com To: RE-wrenches re-wrenches@lists.re-wrenches.org mailto:re-wrenches@lists.re-wrenches.org, Date: 06/28/2015 10:30 PM Subject:Re: [RE-wrenches] Battery Bank to Inverter Wiring Sent by: RE-wrenches re-wrenches-boun...@lists.re-wrenches.org mailto:re-wrenches-boun...@lists.re-wrenches.org On 6/28/2015 9:20 AM, Allan Sindelar wrote: I'm not an EE, but I can't see what difference twisting would make in the absence of a building/collapsing field as is normal with AC. It is little known that with the typical inverters that use the heavy power transformers, have a lot of AC 120 Hz (or 100 Hz for 50 Hz systems) current mixed in with that DC battery current. The AC output current reflects back to the input as ripple current. This is why you want to have at least short as possible Sbattery cable runs AND keep the wires as close together as possible. Twisting the battery cables may help a bit but that is probably overkill. The problem has to do with inductance in the battery cables. You can use as big of cable as you can fit in to reduce resistance, but that will not help to lower the inductance. The problems you can sometimes have with high inductance is that L-C resonance at the inverter can raise the peak voltages seen at the inverter input terminals and can be hard on the inverter. Then again, the high frequency, lighter weight inverters will typically keep most of that ripple inside, between the DC input and AC output and battery cable inductance will not be as much of a problem on the battery cables. boB Gudgel On 6/28/2015 9:20 AM, Allan Sindelar wrote: As a matter of course I have always run the positive and negative conductors of high-current cable pairs together, but have never deliberately twisted them, and have never known of any related problems. The most obvious example of this would be 4/0 battery/inverter cables in a 24V system, with a 250A GJ-class breaker or (prior to that) a 300A or 400A Class T fuse. It's pretty
Re: [RE-wrenches] Battery Bank to Inverter Wiring
In my experience, adding large electrolytic filter caps at the inverter seems to help quite a bit with ac ripple issues and increases inverter efficiency a bit as well. Roy Rakobitsch NABCEP Certified Small Wind Installer® NABCEP Certified Solar PV Installer® Certified Advanced Tower Climbing, Safety Rescue Wind/PV Design Engineer Windsine LLC 631-514-4166 www.windsine.org On Jun 29, 2015 5:05 PM, Ray Walters r...@solarray.com wrote: This is fascinating because while I knew the DC cables had an AC component, I never realized how much inductance played in the volt drop to the inverter. Thanks for bringing this to our attention Jarmo. Which brings up another question based on Benn's question: isn't the battery itself part of the inductive loop? and would the lead inside and steel cases act to increase the inductance? Should we consider changing battery layouts not just to shorten cable lengths, but to counter inductance in the batteries themselves? If needed, we could actually wire the batteries to twist by putting every other 2 v cell in the opposite row. My guess is that it wouldn't be worth it, but I've been wrong many times... R.Ray Walters CTO, Solarray, Inc Nabcep Certified PV Installer, Licensed Master Electrician Solar Design Engineer303 505-8760 On 6/29/2015 3:55 PM, Benn Kilburn wrote: What about when you have the (+) and (-) terminals at opposite ends of a larger battery bank? Sure you can run the conductors side-by-side once they meet up on their way to the inverter, but would you consider the distance between the end terminals a large loop? Ideally the battery string is laid out so the end terminals are close together and close to the inverter, but this isn't always the case. Benn Kilburn SkyFire Energy Inc. 780-906-7807 On Jun 29, 2015, at 10:28 AM, jarmo.venalai...@schneider-electric.com wrote: Hi: From the comments so far, it appears that within the wrenches group, good practices are the rule and DC cables are kept side by side, so the problem I mentioned hasn't come up much. I have seen large loop battery cables a couple of times in solar installs myself out on islands way down south. Also on boats/RV's/motor homes. Please keep the cable loop in mind when you do bench tests of inverters, as it may screw up the results and make it seem like there is something wrong with the inverter. JARMO _ * Jarmo Venalainen* | * Schneider Electric ** | Xantrex Brand* | *CANADA* | *Sales Application Engineer* * Phone:* +604-422-2528 | *Tech Support:* 800-670-0707 | *Mobile:* +604-505-0291 * Email:* *jarmo.venalai...@schneider-electric.com* jarmo.venalai...@schneider-electric.com | *Site:** www.Xantrex.com* http://www.xantrex.com/ | *Address:* 3700 Gilmore Way, Burnaby, BC V5G4M1 mime-attachment.gif http://www.xantrexrebate.com/ mime-attachment.gif http://www.xantrex.com/ mime-attachment.gif https://www.facebook.com/Xantrex mime-attachment.gif https://twitter.com/Xantrex mime-attachment.gif https://twitter.com/Xantrex *** Please consider the environment before printing this e-mail From: b...@midnitesolar.com b...@midnitesolar.com To: RE-wrenches re-wrenches@lists.re-wrenches.org, Date: 06/28/2015 10:30 PM Subject: Re: [RE-wrenches] Battery Bank to Inverter Wiring Sent by: RE-wrenches re-wrenches-boun...@lists.re-wrenches.org -- On 6/28/2015 9:20 AM, Allan Sindelar wrote: I'm not an EE, but I can't see what difference twisting would make in the absence of a building/collapsing field as is normal with AC. It is little known that with the typical inverters that use the heavy power transformers, have a lot of AC 120 Hz (or 100 Hz for 50 Hz systems) current mixed in with that DC battery current. The AC output current reflects back to the input as ripple current. This is why you want to have at least short as possible Sbattery cable runs AND keep the wires as close together as possible. Twisting the battery cables may help a bit but that is probably overkill. The problem has to do with inductance in the battery cables. You can use as big of cable as you can fit in to reduce resistance, but that will not help to lower the inductance. The problems you can sometimes have with high inductance is that L-C resonance at the inverter can raise the peak voltages seen at the inverter input terminals and can be hard on the inverter. Then again, the high frequency, lighter weight inverters will typically keep most of that ripple inside, between the DC input and AC output and battery cable inductance will not be as much of a problem on the battery cables. boB Gudgel On 6/28/2015 9:20 AM, Allan Sindelar wrote: As a matter of course I have always run the positive and negative conductors of high-current cable pairs together, but have never
Re: [RE-wrenches] Battery Bank to Inverter Wiring
Wrenches We always try to minimize in connection cables as well as home run cables to the shorted length possible, restating batteries to aid this should always be considered as well as positive and negative runs Jerry Sent via the Samsung Galaxy S™ III, an ATT 4G LTE smartphone div Original message /divdivFrom: Ray Walters r...@solarray.com /divdivDate:06/29/2015 12:05 PM (GMT-10:00) /divdivTo: RE-wrenches re-wrenches@lists.re-wrenches.org /divdivSubject: Re: [RE-wrenches] Battery Bank to Inverter Wiring /divdiv /divThis is fascinating because while I knew the DC cables had an AC component, I never realized how much inductance played in the volt drop to the inverter. Thanks for bringing this to our attention Jarmo. Which brings up another question based on Benn's question: isn't the battery itself part of the inductive loop? and would the lead inside and steel cases act to increase the inductance? Should we consider changing battery layouts not just to shorten cable lengths, but to counter inductance in the batteries themselves? If needed, we could actually wire the batteries to twist by putting every other 2 v cell in the opposite row. My guess is that it wouldn't be worth it, but I've been wrong many times... R.Ray Walters CTO, Solarray, Inc Nabcep Certified PV Installer, Licensed Master Electrician Solar Design Engineer 303 505-8760 On 6/29/2015 3:55 PM, Benn Kilburn wrote: What about when you have the (+) and (-) terminals at opposite ends of a larger battery bank? Sure you can run the conductors side-by-side once they meet up on their way to the inverter, but would you consider the distance between the end terminals a large loop? Ideally the battery string is laid out so the end terminals are close together and close to the inverter, but this isn't always the case. Benn Kilburn SkyFire Energy Inc. 780-906-7807 On Jun 29, 2015, at 10:28 AM, jarmo.venalai...@schneider-electric.com wrote: Hi: From the comments so far, it appears that within the wrenches group, good practices are the rule and DC cables are kept side by side, so the problem I mentioned hasn't come up much. I have seen large loop battery cables a couple of times in solar installs myself out on islands way down south. Also on boats/RV's/motor homes. Please keep the cable loop in mind when you do bench tests of inverters, as it may screw up the results and make it seem like there is something wrong with the inverter. JARMO _ Jarmo Venalainen | Schneider Electric | Xantrex Brand | CANADA | Sales Application Engineer Phone: +604-422-2528 | Tech Support: 800-670-0707 | Mobile: +604-505-0291 Email: jarmo.venalai...@schneider-electric.com | Site: www.Xantrex.com | Address: 3700 Gilmore Way, Burnaby, BC V5G4M1 mime-attachment.gif mime-attachment.gif mime-attachment.gif mime-attachment.gif mime-attachment.gif *** Please consider the environment before printing this e-mail From: b...@midnitesolar.com b...@midnitesolar.com To: RE-wrenches re-wrenches@lists.re-wrenches.org, Date: 06/28/2015 10:30 PM Subject:Re: [RE-wrenches] Battery Bank to Inverter Wiring Sent by:RE-wrenches re-wrenches-boun...@lists.re-wrenches.org On 6/28/2015 9:20 AM, Allan Sindelar wrote: I'm not an EE, but I can't see what difference twisting would make in the absence of a building/collapsing field as is normal with AC. It is little known that with the typical inverters that use the heavy power transformers, have a lot of AC 120 Hz (or 100 Hz for 50 Hz systems) current mixed in with that DC battery current. The AC output current reflects back to the input as ripple current. This is why you want to have at least short as possible Sbattery cable runs AND keep the wires as close together as possible. Twisting the battery cables may help a bit but that is probably overkill. The problem has to do with inductance in the battery cables. You can use as big of cable as you can fit in to reduce resistance, but that will not help to lower the inductance. The problems you can sometimes have with high inductance is that L-C resonance at the inverter can raise the peak voltages seen at the inverter input terminals and can be hard on the inverter. Then again, the high frequency, lighter weight inverters will typically keep most of that ripple inside, between the DC input and AC output and battery cable inductance will not be as much of a problem on the battery cables. boB Gudgel On 6/28/2015 9:20 AM, Allan Sindelar wrote: As a matter of course I have always run the positive and negative conductors of high-current cable
Re: [RE-wrenches] Battery Bank to Inverter Wiring
Hi: It's not possible to have no loop area at all, but cables should be run in ways to minimize the loop area. If you run the + or - along the side of the batteries for example, then that has the effect of minimizing the total loop. JARMO _ Jarmo Venalainen | Schneider Electric | Xantrex Brand | CANADA | Sales Application Engineer Phone: +604-422-2528 | Tech Support: 800-670-0707 | Mobile: +604-505-0291 Email: jarmo.venalai...@schneider-electric.com | Site: www.Xantrex.com | Address: 3700 Gilmore Way, Burnaby, BC V5G4M1 *** Please consider the environment before printing this e-mail From: Benn Kilburn b...@skyfireenergy.com To: RE-wrenches re-wrenches@lists.re-wrenches.org, Date: 06/29/2015 02:55 PM Subject: Re: [RE-wrenches] Battery Bank to Inverter Wiring Sent by: RE-wrenches re-wrenches-boun...@lists.re-wrenches.org What about when you have the (+) and (-) terminals at opposite ends of a larger battery bank? Sure you can run the conductors side-by-side once they meet up on their way to the inverter, but would you consider the distance between the end terminals a large loop? Ideally the battery string is laid out so the end terminals are close together and close to the inverter, but this isn't always the case. Benn Kilburn SkyFire Energy Inc. 780-906-7807 On Jun 29, 2015, at 10:28 AM, jarmo.venalai...@schneider-electric.com wrote: Hi: From the comments so far, it appears that within the wrenches group, good practices are the rule and DC cables are kept side by side, so the problem I mentioned hasn't come up much. I have seen large loop battery cables a couple of times in solar installs myself out on islands way down south. Also on boats/RV's/motor homes. Please keep the cable loop in mind when you do bench tests of inverters, as it may screw up the results and make it seem like there is something wrong with the inverter. JARMO _ Jarmo Venalainen | Schneider Electric | Xantrex Brand | CANADA | Sales Application Engineer Phone: +604-422-2528 | Tech Support: 800-670-0707 | Mobile: +604-505-0291 Email: jarmo.venalai...@schneider-electric.com | Site: www.Xantrex.com | Address: 3700 Gilmore Way, Burnaby, BC V5G4M1 mime-attachment.gif mime-attachment.gif mime-attachment.gif mime-attachment.gif mime-attachment.gif *** Please consider the environment before printing this e-mail From: b...@midnitesolar.com b...@midnitesolar.com To: RE-wrenches re-wrenches@lists.re-wrenches.org, Date: 06/28/2015 10:30 PM Subject: Re: [RE-wrenches] Battery Bank to Inverter Wiring Sent by: RE-wrenches re-wrenches-boun...@lists.re-wrenches.org On 6/28/2015 9:20 AM, Allan Sindelar wrote: I'm not an EE, but I can't see what difference twisting would make in the absence of a building/collapsing field as is normal with AC. It is little known that with the typical inverters that use the heavy power transformers, have a lot of AC 120 Hz (or 100 Hz for 50 Hz systems) current mixed in with that DC battery current. The AC output current reflects back to the input as ripple current. This is why you want to have at least short as possible Sbattery cable runs AND keep the wires as close together as possible. Twisting the battery cables may help a bit but that is probably overkill. The problem has to do with inductance in the battery cables. You can use as big of cable as you can fit in to reduce resistance, but that will not help to lower the inductance. The problems you can sometimes have with high inductance is that L-C resonance at the inverter can raise the peak voltages seen at the inverter input terminals and can be hard on the inverter. Then again, the high frequency, lighter weight inverters will typically keep most of that ripple inside, between the DC input and AC output and battery cable inductance will not be as much of a problem on the battery cables. boB Gudgel On 6/28/2015 9:20 AM, Allan Sindelar wrote: As a matter of course I have always run the positive and negative conductors of high-current cable pairs together, but have never deliberately twisted them, and have never known of any related problems. The most obvious example of this would be 4/0 battery/inverter cables in a 24V system, with a 250A GJ-class breaker or (prior to that) a 300A or 400A Class T fuse. It's pretty tough to thread a twisted pair of 4/0 USE/RHH/RHW cables through a 2 elbow or LB from inverter enclosure to battery enclosure. I'm not an EE, but I can't see what difference twisting would make in the absence of a building/collapsing field as is normal with AC. I have twisted AC conductors together in the past when clients have expressed concerns about EMF from their equipment and wiring, but only AC. Allan Allan Sindelar al
Re: [RE-wrenches] Battery Bank to Inverter Wiring
As a matter of course I have always run the positive and negative
conductors of high-current cable pairs together, but have never
deliberately twisted them, and have never known of any related
problems.
The most obvious example of this would be 4/0 battery/inverter
cables in a 24V system, with a 250A GJ-class breaker or (prior to
that) a 300A or 400A Class T fuse. It's pretty tough to thread a
twisted pair of 4/0 USE/RHH/RHW cables through a 2" elbow or LB from
inverter enclosure to battery enclosure.
I'm not an EE, but I can't see what difference twisting would make
in the absence of a building/collapsing field as is normal with AC.
I have twisted AC conductors together in the past when clients have
expressed concerns about EMF from their equipment and wiring, but
only AC.
Allan
Allan Sindelar
al...@sindelarsolar.com
NABCEP Certified PV
Installation Professional
NABCEP Certified Technical Sales Professional
New Mexico EE98J Journeyman Electrician
Founder (Retired), Positive
Energy,
Inc.
505 780-2738 cell
On 6/27/2015 2:40 AM, John wrote:
That
is why for years we have been twisting those leads around
each other. I was told it was to cancel out the opposing
fields on the wires, but for whatever the correct technical
reason is, we have always twisted those heavy
wires. John V.
From: RE-wrenches
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On
Behalf Of jarmo.venalai...@schneider-electric.com
Sent: Saturday, 27 June 2015 5:45 a.m.
To: RE-wrenches
Subject: [RE-wrenches] Battery Bank to Inverter
Wiring
Hi:
From
time to time over the years I've come across systems where
the routing of DC cables between the batteries and the
inverter has been the cause of issues.
I'm
not referring to wire thickness or quality of terminations.
For the purposes of this discussion, just assume that wire
thickness and terminations are perfect.
What
I am referring to is the routing of the positive and
negative battery cables. In particular, the loop area
within the + and - cables as shown in the image below,
The
problem I've seen in systems with a large loop in the setup
is that the inverter does not provide good surge power and
can even go into low voltage shutdown during large surges.
Recently
this happened again and I wanted to get a better feel for
it, so I did some math.
For
a cable length of about 12', the loop is an inductor which
has a value of inductance of about 1 uH for side by side
cables and as much as 6 uH for cables about 1 foot apart.
This
inductance is greatly multiplied by any ferrous metal in the
loop and can easily be in the range of 10's to 100's of uH.
Examples being cables which run in steel conduits or along
the steel frame of a motor home.
Inductance
causes a voltage drop proportional to the rate at which the
current is changing. To get an idea of how large that rate
can be for typical inverters, I did surge tests with a 5kW
inverter and found that the rate of change of current can be
as high as 100A per milli-second or 100,000 Amps/second.
Given
that, the voltage drop of the wire inductance is then ,
Vdrop = (rate of change of current) x (inductance),
Vdrop
for 1 uH = (100,000 A/s) x (0.01 H) = 0.1V
Vdrop
for 10 uH = (100,000 A/s) x (0.01 H) = 1.0V
Vdrop
for 100 uH = (100,000 A/s) x (0.01 H) = 10.0V clearly
this is a problem.
Have
any of the wrenches had systems with this issue? If so, how
often.
JARMO
_
Jarmo Venalainen
| Schneider Electric
| Xantrex Brand | C
Re: [RE-wrenches] Battery Bank to Inverter Wiring
On 6/28/2015 9:20 AM, Allan Sindelar wrote: I'm not an EE, but I can't see what difference twisting would make in the absence of a building/collapsing field as is normal with AC. It is little known that with the typical inverters that use the heavy power transformers, have a lot of AC 120 Hz (or 100 Hz for 50 Hz systems) current mixed in with that DC battery current. The AC output current reflects back to the input as ripple current. This is why you want to have at least short as possible Sbattery cable runs AND keep the wires as close together as possible. Twisting the battery cables may help a bit but that is probably overkill. The problem has to do with inductance in the battery cables. You can use as big of cable as you can fit in to reduce resistance, but that will not help to lower the inductance. The problems you can sometimes have with high inductance is that L-C resonance at the inverter can raise the peak voltages seen at the inverter input terminals and can be hard on the inverter. Then again, the high frequency, lighter weight inverters will typically keep most of that ripple inside, between the DC input and AC output and battery cable inductance will not be as much of a problem on the battery cables. boB Gudgel On 6/28/2015 9:20 AM, Allan Sindelar wrote: As a matter of course I have always run the positive and negative conductors of high-current cable pairs together, but have never deliberately twisted them, and have never known of any related problems. The most obvious example of this would be 4/0 battery/inverter cables in a 24V system, with a 250A GJ-class breaker or (prior to that) a 300A or 400A Class T fuse. It's pretty tough to thread a twisted pair of 4/0 USE/RHH/RHW cables through a 2 elbow or LB from inverter enclosure to battery enclosure. I'm not an EE, but I can't see what difference twisting would make in the absence of a building/collapsing field as is normal with AC. I have twisted AC conductors together in the past when clients have expressed concerns about EMF from their equipment and wiring, but only AC. Allan *Allan Sindelar* al...@sindelarsolar.com mailto:al...@sindelarsolar.com NABCEP Certified PV Installation Professional NABCEP Certified Technical Sales Professional New Mexico EE98J Journeyman Electrician Founder (Retired), Positive Energy, Inc. *505 780-2738 cell* ** On 6/27/2015 2:40 AM, John wrote: That is why for years we have been twisting those leads around each other. I was told it was to cancel out the opposing fields on the wires, but for whatever the correct technical reason is, we have always twisted those heavy wires. John V. *From:*RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] *On Behalf Of *jarmo.venalai...@schneider-electric.com *Sent:* Saturday, 27 June 2015 5:45 a.m. *To:* RE-wrenches *Subject:* [RE-wrenches] Battery Bank to Inverter Wiring Hi: From time to time over the years I've come across systems where the routing of DC cables between the batteries and the inverter has been the cause of issues. I'm not referring to wire thickness or quality of terminations. For the purposes of this discussion, just assume that wire thickness and terminations are perfect. What I am referring to is the routing of the positive and negative battery cables. In particular, the loop area within the + and - cables as shown in the image below, The problem I've seen in systems with a large loop in the setup is that the inverter does not provide good surge power and can even go into low voltage shutdown during large surges. Recently this happened again and I wanted to get a better feel for it, so I did some math. For a cable length of about 12', the loop is an inductor which has a value of inductance of about 1 uH for side by side cables and as much as 6 uH for cables about 1 foot apart. This inductance is greatly multiplied by any ferrous metal in the loop and can easily be in the range of 10's to 100's of uH. Examples being cables which run in steel conduits or along the steel frame of a motor home. Inductance causes a voltage drop proportional to the rate at which the current is changing. To get an idea of how large that rate can be for typical inverters, I did surge tests with a 5kW inverter and found that the rate of change of current can be as high as 100A per milli-second or 100,000 Amps/second. Given that, the voltage drop of the wire inductance is then , Vdrop = (rate of change of current) x (inductance), Vdrop for 1 uH = (100,000 A/s) x (0.01 H) = 0.1V Vdrop for 10 uH = (100,000 A/s) x (0.01 H) = 1.0V Vdrop for 100 uH = (100,000 A/s) x (0.01 H) = 10.0V clearly this is a problem. Have any of the wrenches had systems with this issue? If so, how often. JARMO ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address
[RE-wrenches] Battery Bank to Inverter Wiring
Hi: From time to time over the years I've come across systems where the routing of DC cables between the batteries and the inverter has been the cause of issues. I'm not referring to wire thickness or quality of terminations. For the purposes of this discussion, just assume that wire thickness and terminations are perfect. What I am referring to is the routing of the positive and negative battery cables. In particular, the loop area within the + and - cables as shown in the image below, The problem I've seen in systems with a large loop in the setup is that the inverter does not provide good surge power and can even go into low voltage shutdown during large surges. Recently this happened again and I wanted to get a better feel for it, so I did some math. For a cable length of about 12', the loop is an inductor which has a value of inductance of about 1 uH for side by side cables and as much as 6 uH for cables about 1 foot apart. This inductance is greatly multiplied by any ferrous metal in the loop and can easily be in the range of 10's to 100's of uH. Examples being cables which run in steel conduits or along the steel frame of a motor home. Inductance causes a voltage drop proportional to the rate at which the current is changing. To get an idea of how large that rate can be for typical inverters, I did surge tests with a 5kW inverter and found that the rate of change of current can be as high as 100A per milli-second or 100,000 Amps/second. Given that, the voltage drop of the wire inductance is then , Vdrop = (rate of change of current) x (inductance), Vdrop for 1 uH = (100,000 A/s) x (0.01 H) = 0.1V Vdrop for 10 uH = (100,000 A/s) x (0.01 H) = 1.0V Vdrop for 100 uH = (100,000 A/s) x (0.01 H) = 10.0Vclearly this is a problem. Have any of the wrenches had systems with this issue? If so, how often. JARMO _ Jarmo Venalainen | Schneider Electric | Xantrex Brand | CANADA | Sales Application Engineer Phone: +604-422-2528 | Tech Support: 800-670-0707 | Mobile: +604-505-0291 Email: jarmo.venalai...@schneider-electric.com | Site: www.Xantrex.com | Address: 3700 Gilmore Way, Burnaby, BC V5G4M1 *** Please consider the environment before printing this e-mail ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Battery Bank to Inverter Wiring
That is why for years we have been twisting those leads around each other. I was told it was to cancel out the opposing fields on the wires, but for whatever the correct technical reason is, we have always twisted those heavy wires. John V. From: RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of jarmo.venalai...@schneider-electric.com Sent: Saturday, 27 June 2015 5:45 a.m. To: RE-wrenches Subject: [RE-wrenches] Battery Bank to Inverter Wiring Hi: From time to time over the years I've come across systems where the routing of DC cables between the batteries and the inverter has been the cause of issues. I'm not referring to wire thickness or quality of terminations. For the purposes of this discussion, just assume that wire thickness and terminations are perfect. What I am referring to is the routing of the positive and negative battery cables. In particular, the loop area within the + and - cables as shown in the image below, The problem I've seen in systems with a large loop in the setup is that the inverter does not provide good surge power and can even go into low voltage shutdown during large surges. Recently this happened again and I wanted to get a better feel for it, so I did some math. For a cable length of about 12', the loop is an inductor which has a value of inductance of about 1 uH for side by side cables and as much as 6 uH for cables about 1 foot apart. This inductance is greatly multiplied by any ferrous metal in the loop and can easily be in the range of 10's to 100's of uH. Examples being cables which run in steel conduits or along the steel frame of a motor home. Inductance causes a voltage drop proportional to the rate at which the current is changing. To get an idea of how large that rate can be for typical inverters, I did surge tests with a 5kW inverter and found that the rate of change of current can be as high as 100A per milli-second or 100,000 Amps/second. Given that, the voltage drop of the wire inductance is then , Vdrop = (rate of change of current) x (inductance), Vdrop for 1 uH = (100,000 A/s) x (0.01 H) = 0.1V Vdrop for 10 uH = (100,000 A/s) x (0.01 H) = 1.0V Vdrop for 100 uH = (100,000 A/s) x (0.01 H) = 10.0Vclearly this is a problem. Have any of the wrenches had systems with this issue? If so, how often. JARMO _ Jarmo Venalainen | Schneider Electric | Xantrex Brand | CANADA | Sales Application Engineer Phone: +604-422-2528 | Tech Support: 800-670-0707 | Mobile: +604-505-0291 Email: mailto:jarmo.venalai...@schneider-electric.com jarmo.venalai...@schneider-electric.com | Site: http://www.xantrex.com/ www.Xantrex.com | Address: 3700 Gilmore Way, Burnaby, BC V5G4M1 http://www.xantrexrebate.com/ http://www.xantrex.com/ https://www.facebook.com/Xantrex https://twitter.com/Xantrex https://twitter.com/Xantrex *** Please consider the environment before printing this e-mail ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Battery Bank to Inverter Wiring
Wrenches Going back many many years, twisting the pairs together was the preferred way to run the cables between the inverter and batteries, this seamed to reduce noise, I have personally seen improvement of audio conditions. Doing this on the AC side does the opposite and creates noise on sound mixers and powered amps. Jerry On Fri, Jun 26, 2015 at 7:45 AM, jarmo.venalai...@schneider-electric.com wrote: Hi: From time to time over the years I've come across systems where the routing of DC cables between the batteries and the inverter has been the cause of issues. I'm not referring to wire thickness or quality of terminations. For the purposes of this discussion, just assume that wire thickness and terminations are perfect. What I am referring to is the routing of the positive and negative battery cables. In particular, the loop area within the + and - cables as shown in the image below, The problem I've seen in systems with a large loop in the setup is that the inverter does not provide good surge power and can even go into low voltage shutdown during large surges. Recently this happened again and I wanted to get a better feel for it, so I did some math. For a cable length of about 12', the loop is an inductor which has a value of inductance of about 1 uH for side by side cables and as much as 6 uH for cables about 1 foot apart. This inductance is greatly multiplied by any ferrous metal in the loop and can easily be in the range of 10's to 100's of uH. Examples being cables which run in steel conduits or along the steel frame of a motor home. Inductance causes a voltage drop proportional to the rate at which the current is changing. To get an idea of how large that rate can be for typical inverters, I did surge tests with a 5kW inverter and found that the rate of change of current can be as high as 100A per milli-second or 100,000 Amps/second. Given that, the voltage drop of the wire inductance is then , Vdrop = (rate of change of current) x (inductance), Vdrop for 1 uH = (100,000 A/s) x (0.01 H) = 0.1V Vdrop for 10 uH = (100,000 A/s) x (0.01 H) = 1.0V Vdrop for 100 uH = (100,000 A/s) x (0.01 H) = 10.0Vclearly this is a problem. Have any of the wrenches had systems with this issue? If so, how often. JARMO _ * Jarmo Venalainen* | * Schneider Electric ** | Xantrex Brand* | *CANADA* | *Sales Application Engineer* * Phone:* +604-422-2528 | *Tech Support:* 800-670-0707 | *Mobile:* +604-505-0291 * Email:* *jarmo.venalai...@schneider-electric.com* jarmo.venalai...@schneider-electric.com | *Site:** www.Xantrex.com* http://www.xantrex.com/ | *Address:* 3700 Gilmore Way, Burnaby, BC V5G4M1 http://www.xantrexrebate.com/ http://www.xantrex.com/ https://www.facebook.com/Xantrex https://twitter.com/Xantrex https://twitter.com/Xantrex *** Please consider the environment before printing this e-mail ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
