I use volt drop under load, to find loose/ problem connections, but 2/100 of a volt drop could just be due to the resistance between his probes and the battery terminal. DId he take 3 to 5 readings, and then avg his readings to come up with his evaluation? If his reading was accurate, a .02 v drop on a foot of 2/0 cable would match about a 240 amp load. Still not necessarily a problem. Also, I've got a picture of a totally fried, (as in caught on fire) sulfator, if you'd like to share that with your customer. Even if the connection is bad, 99% of the time the cable can be cleaned, repaired, and retightened; you don't throw all the cables away. Best news is that you should get the sell by saving the customer money, and not selling them cables they don't 'need.
R. Walters [email protected] Solar Engineer On Jan 7, 2011, at 10:01 AM, <[email protected]> wrote: > > Hey Everyone... got another one of those "Funny Questions" I'm struggling > with... Seems I have an off grid customer researching battery issues.. and > trying to gather a consensus among vendors.. fair enough... currently they > have 4 strings of 5+ yr old L16 (not my design) that are starting to fail > (no surprises there).. I'm trying to get them into a one or two string > design.. Seems they've been in contact with a "Battery Specialist" (who > previously sold them a couple dozen or so desulphators... which has not > appeared to have significantly affected the lifespan of the bank).. Seems he > also "Discovered" that they would need new cables because he measured up to > 2/100 of a volt drop across some of the connections -- some at the terminal / > flag connections... others from the swedged terminal to the cable... seems he > also outright failed a couple of 16" chunks of 2/0 interconnection cables > because of "voltage drops" in the cables themselves... I've checked around a > little.. I'm told BMI suggests a max .2 volt drop under full load between > battery and starter terminal, and 1.2 Volt drop thru the entire starter > control circuit... I'm at a loss here folks... working on my diplomacy.. > I'm curious if anyone has hard and fast experience with using voltage drop to > evaluate battery interconnections.. and if so, what might the voltage drops > be... thanks all.. db > > Dan Brown > Foxfire Energy Corp. > Renewable Energy Systems > (802)-483-2564 > www.Foxfire-Energy.com > NABCEP #092907-44 > > _______________________________________________ > 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 >
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