[RE-wrenches] Voltage discrepancy
Darryl Thayer
daryl_solar at yahoo.com
Sat Aug 14 15:33:43 PDT 2010
HI Drake
BE CAREFULL I had a battery set explode on me due to a loose connection, it had been charging, and I was investagating and the loose connection sparked and BANG I was fortunatle to have my goggles on. Besure to stop charging then vent, then investiagate.
Also I do not think the water loss is from the controller, question how often they run theri generator.
Darryl
--- On Sat, 8/14/10, boB Gudgel <boB at midnitesolar.com> wrote:
> From: boB Gudgel <boB at midnitesolar.com>
> Subject: Re: [RE-wrenches] Voltage discrepancy
> To: "RE-wrenches" <re-wrenches at lists.re-wrenches.org>
> Date: Saturday, August 14, 2010, 5:10 PM
> Drake Chamberlin wrote:
> > boB,
> >
> > Thanks, I will check all connections when I get
> out there. Is there anyway a loose connection could
> cook the batteries?
>
> A loose connection, if it was like I described, would tend
> to under-charge the batteries. I would
> think that
> if there were ~that~ much of a voltage drop, and
> significant current, you'd have a pretty hot connection
> somewhere. Although, if the connection is bad enough,
> you might just get the CC to get to Absorb or
> Float voltage and that would at least limit the current but
> maybe not enough..
> Of course, loose connections may not be the problem, but
> that's what I look for first.
> I would measure the voltage at the CC terminal block and
> see if it is telling the truth.
>
> If the CC is telling the truth, then she may have a bad
> connection, and then
> it's Warning Will Robinson !!
>
> Could be intermittent too. Then ya may
> want to start wiggling and banging on things.
> It sure worked well with TV sets.
>
> boB
>
>
> >
> > Thanks,
> >
> >
> > Drake
> >
> >
> > At 03:16 PM 8/14/2010, you wrote:
> >> 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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> >>> Athens Electric
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> >>> CO License 3773
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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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