[RE-wrenches] weak voltage

[Bill Loesch]

Mick,

Thanks for sharing. Outstanding troubleshooting (particularly when done 
remotely).

Bill Loesch
Solar 1 - Saint Louis Solar

On 15-Oct-12 8:24 AM, Mick Abraham wrote:
> Hello, Wrenchies~
>
> Mac Lewis wrote about battery strangeness on the Sunny Island system 
> for his clients. Here is a theory to consider, Mac.
>
> I once bought a 48v string of >famous brand< two volt cells in which 
> one cell had been loaded backwards into its case. When hooked up 
> according to the +/- markings on the case, this cell was discharging 
> at the same time the rest of the string was charging so even though 
> the others were running high during the charge, the end to end voltage 
> immediately slumped to relatively low values after the charge was 
> ended. The one cell was effectively missing in action.
>
> My client was a DIY type who was distant from my location but he owned 
> a voltmeter that was still in the box. I coached him through a 
> "voltage walk" up the string and sure enough we found the one 
> increment that was subtracting from overall string voltage instead of 
> adding to it. The >famous< battery supplier said this was impossible, 
> they are checked three times, this never happens & can't happen, blah 
> blah...and they were only convinced when the cell was back in their 
> shop and they could measure this for themselves.
>
> Even after they checked it, they said, "It's the first time in our 20 
> + years with that brand that we have ever seen this." Black swan.
>
> At my request, the company paid to ship back the entire string and 
> ship all new replacement cells to the client. This seemed important 
> because the other 23 cells had been subjected to a high voltage per 
> cell and had gotten a bit hot before the problem was discovered.
>
> ++++++++++++++++++++++++++++
>
> Perhaps this theory is worth checking on site. Whatever you find to 
> resolve this problem, Mac, be sure to report back on list so we can 
> all learn.
>
> Jolliness,
>
> Mick Abraham, Proprietor
> www.abrahamsolar.com <http://www.abrahamsolar.com>
>
> Voice: 970-731-4675
>
>
> _______________________________________________
> List sponsored by Home Power magazine
>
> List Address: RE-wrenches at 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
>
>
>
> No virus found in this message.
> Checked by AVG - www.avg.com <http://www.avg.com>
> Version: 2012.0.2221 / Virus Database: 2441/5332 - Release Date: 10/14/12
>




-----
No virus found in this message.
Checked by AVG - www.avg.com
Version: 2012.0.2221 / Virus Database: 2441/5332 - Release Date: 10/14/12
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachments/20121015/df007940/attachment-0004.html>