[RE-wrenches] Voltage discrepancy

[boB Gudgel]

Drake Chamberlin wrote:
> I called her back just now, and the voltage readings on the Mate, MX 
> and Trimetric all match.  Humm.  
>
> The batteries are 4, 4 1/2 year old, U.S. Battery L-16s wired in 24 
> volt configuration.  It seems that I remember postings of Wrenches 
> having problems with these batteries.  There is about 1 KW STC of PV 
> on the roof. 
>
>

Might want to be careful of loose connections.  Maybe the MX was putting 
out some high(ish) current and there
was a voltage drop across that connection, and now they are reading the 
same because the current is
lower from the MX.  i.e.  high voltage at the terminals of the CC and 
lower at the actual battery terminals.

boB





>
> At 12:12 PM 8/14/2010, you wrote:
>> Any way she can get a real voltmeter?  the MX60 has voltage 
>> calibration, so does the FX  it sounds like something is over 
>> charging, perhaps the generator run?   additonal details on battery 
>> bank size, array size and typical load. 
>>  
>> Darryl
>>
>> --- On *Sat, 8/14/10, Drake Chamberlin 
>> /<drake.chamberlin at redwoodalliance.org>/* wrote:
>>
>>
>>     From: Drake Chamberlin <drake.chamberlin at redwoodalliance.org>
>>     Subject: [RE-wrenches] Voltage discrepancy
>>     To: "RE-wrenches" <re-wrenches at lists.re-wrenches.org>
>>     Date: Saturday, August 14, 2010, 8:58 AM
>>
>>     Hello Wrenches,
>>
>>     I just got off the phone with an off grid system owner who has a
>>     voltage discrepancy showing between the reading on her MX-60 and
>>     both her Mate and Trimetric meter.  The MX-60 shows 28.8 V and
>>     the Trimetric and the Mate both show around 25 volts.  The
>>     batteries are using a tremendous amount of water.
>>
>>     Has anyone seen this scenario before?  Do you think the MX-60 is
>>     bad?
>>
>>     Thanks,
>>
>>     Drake Chamberlin
>>     Athens Electric
>>     OH License 44810
>>     CO License 3773
>>     NABCEP TM  Certified PV Installer
>>     Office - 740-448-7328
>>     Mobile - 740-856-9648
>>
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> Drake Chamberlin
> Athens Electric
> OH License 44810
> CO License 3773
> NABCEP TM  Certified PV Installer
> Office - 740-448-7328
> Mobile - 740-856-9648
>
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