[RE-wrenches] intermittent battery problem

[David Katz]

Ron
If the customer does not get enough elecrolyte into the hydrometer to lift the float, the level could be in the green on a dead battery. If they don't have a dead cell they must have a fully discharged battery. An 1100 ah battery seeing a 100 amp charge would be closer to 30 volts after 2 hours of charging if it had even a 50% charge.
David Katz

From: Ron Young [mailto:solareagle at solareagle.com]
Sent: Saturday, October 08, 2011 11:31 AM
To: RE-wrenches <re-wrenches at lists.re-wrenches.org>
Subject: Re: [RE-wrenches] intermittent battery problem

There is no amp hour meter in the system. The dump load on the Whisper sounds like a possibility... Batteries are 4ks21 Surrettes with an 1100 a/h rating @20hr rate and should have plenty of life left in them. They have been eq'd on a regular basis and maintenance has been good. Alas the customer doesn't own a multimeter so can't check the individual battery voltages but has checked each cell with tubular hydrometer and tell me that all cells are in the green. They may misread a hydrometer but the colour is easy to see so I'm pretty sure they don't have a bad cell.

Ron

earthRight Products - Solareagle.com<http://Solareagle.com>
Alternative Energy Solutions ~ Renewable Energy Products

On 2011-10-08, at 11:20 AM, jay peltz wrote:

HI Ron,

Do you have an amp hr meter in the system?

When you say 15 min of genny brings the batteries back up, back up to what as you also say, 2 hrs later they are at 25.8v?

I would guess the problem is the dump load controller on the Whisper, its turing on for some reason, draining the batteries.

But for me without an amp hr meter, hard to really know what is happening overnight ie was there really a drain on the system?

jay

peltz power

On Oct 8, 2011, at 11:01 AM, Ron Young wrote:

Howdy Wrenches,

One of my customers that lives 3 hours out in the back country is having an intermittent problem that I haven't encountered before. The batteries drop rapidly in voltage but hydrometer readings are in the green. Turning off the inverter and just using DC doesn't change anything. Meters on the Mate, Outback MX and Whisper controller are all the same so it's not a metering problem. On the way to bed the batteries were at 25.4, overnight with no loads they dropped to 22.9 then a short 15 min. charge with a generator brings the batteries back up and two hours later they are at 25.8. This scenario has occurred several times and then doesn't appear for a day or two.

It doesn't seem to be sulfation as the batteries are reading good on the hydrometer every time. All cells check out. The inverter doesn't seem to be the problem. They have a Sunfrost on a separate DC circuit. It sounds like an intermittent circuit problem or electronics issue. Customer has checked and tightened all the connections he can get at but hasn't been inside the components. Would appreciate any suggestions or clues before I make the trip.

Ron Young

earthRight Products - Solareagle.com<http://Solareagle.com/>
Alternative Energy Solutions ~ Renewable Energy Products


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