Also, it sounds like you're losing almost 7 volts at times, which would correspond to 3 to 4 batteries in failure. I think that would be very unlikely, hence why I still vote for the connectors being at fault. Possibly, it may just be one of the main connectors, and as others pointed out already: it probably will only show itself under load. Don't forget to check the connections at the main disco and inverter too. I had a system act very similar that was just a single connection that the customer had loosened and forgot to retighten.
R. Walters [email protected] Solar Engineer On Apr 20, 2011, at 5:01 PM, Allan Sindelar wrote: > It wouldn't cost much to replace the 5 interconnects, if only to eliminate > the issues that Ray has mentioned from consideration. > > Also, Rich, you didn't mention if all of the terminals got hot, or only > one/few/some. If the terminal contacts or the interconnects are at fault, I > would expect that some would be noticeably hotter than others, corresponding > to specific high-resistance issues at those terminals. > Allan > > Allan Sindelar > [email protected] > NABCEP Certified Photovoltaic Installer > NABCEP Certified Technical Sales Professional > New Mexico EE98J Journeyman Electrician > Positive Energy, Inc. > 3201 Calle Marie > Santa Fe, New Mexico 87507 > 505 424-1112 > www.positiveenergysolar.com > > > > > On 4/20/2011 2:38 PM, R Ray Walters wrote: >> >> Sounds like problem connections, if all the cells are an even 2.12 v. >> I wouldn't solder 4/0 connections, the solder can run back up the cable >> stranding, and make the cables too stiff to fully connect with the battery >> terminal. >> I had a battery terminal meltdown due to this. We quit using thick bussbars, >> soldered cables, and stiff (THHN) cables at battery terminals. >> Also if not soldered properly, you can actually create more resistance in >> the connection due to oxidation and pockets of flux. >> Cables from the manufacturers (HUP, Outback, Trace) are not soldered BTW. >> Its possible that heating the terminals when soldered (with a torch?) may >> have created a layer of oxidation that is causing the resistance (internally >> or externally) >> Sand the contact surfaces, and see if that helps. >> >> Get an infrared thermometer (fairly cheap these days at Sears or automotive >> store) and check all the connections under load. >> Also, check the voltage drops on your cables under load, you should be able >> to find where all that voltage is going, and it should match your infrared >> readings. >> I'd also take out another set of cables to see what that does. >> >> R. Walters >> [email protected] >> Solar Engineer >> >> >> >> >> On Apr 20, 2011, at 1:15 PM, Bob-O Schultze wrote: >> >>> Rich, >>> It sounds like you've got a rotter or two. Given the short age of the pack, >>> that's my suspicion. Try checking the individual battery voltages when >>> under load and fairly well discharged. I've seen a new battery bank all >>> show good SG and individual voltages while resting but one or more >>> batteries tank badly under load. Poor manufacturing QC is the cause. >>> good luck, Bob-O >>> >>> On Apr 20, 2011, at 12:03 PM, Rich Nicol wrote: >>> >>> RE Wrenches >>> My question regards a system (installed by homeowner / friend) where they >>> recently upgraded their t105 battery bank to Trojan RE series L16 2 volt >>> cells. The battery bank consists of 6 batteries in series for a 12 volt >>> system. The interconnects are 12” long 4/0 cables with crimped and >>> soldered lugs. Main cables are 6’ long 4/0 cables. >>> The first issue is high terminal temperature during periods of heavy draw >>> (~100 amps @ 12v when water pump is on). Due to the issue the owner has >>> been only running the water pump when charging the batteries with his >>> generator since the transfer switch on the Outback inverter has transferred >>> his household circuits from the battery bank to the generator. Obviously >>> this is an inconvenience. Before the end of life on his T105’s he had no >>> issues with the 6 volt cells in series/parallel using only #2 AWG >>> interconnects. >>> Most recently he’s experienced an issue where the inverter will not come on >>> at all and when attempted to come by switching on his main DC breaker the >>> voltage at the batteries sags from 12.5 to ~5V! This issue is not with the >>> inverter since I loaned him a back up Trace DR I keep around as a loaner >>> but it too would not come on and voltage sagged as well. This sag is with >>> no demand since it sags immediately when the DC breaker is switched on when >>> connected to the inverter even though the inverter has not been switched >>> on. >>> I stopped by this AM to check out the situation, specific gravity of all >>> cells is good, open circuit voltage on each cell is matched at 2.12 volts. >>> The battery bank is only about 4 months old. >>> Any insight would be greatly appreciated. >>> >>> Battery specs: >>> 2 volt, Rated Capacity @ 5 Hr rate=909 AH, 20 hr rate = 1110 AH, 100 hr >>> rate = 1235. >>> >>> Thanks for your help! >>> Rich >>> >>> >>> >>> _______________________________________________ >>> List sponsored by Home Power magazine >>> >>> List Address: [email protected] >>> >>> 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: [email protected] >> >> 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: [email protected] > > 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: [email protected] 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
