Battery Problem

[RogerAS]

Hi All,

I went to South Dakota to put a roof on the house we own up there and the battery bank developed a problem while I was gone. The wife really feaked as nothing like this has happened before and I can't figure it out much less her.

The batteries, a bank of 8-6V golfs set for 12V less than 3 old, now won't go over 14V no matter how much amperage I shoot into them or for how long. I ran the genset all night. I checked the acid level and all are good. I'm thinking I have a bad cell, but haven't pulled them down to do a hydrometer check yet. The strange part is that the batteries seem to hold that voltage well and don't drop rapidly at all. I've also checked the connections for cleaniness and tightness.

I'm scratching my head! Any ideas?

RogerAS

[brock]

Are you sure they are fully charged?  I know you said youcharged them all night, but at what amperage?  If they were really low and charging at 20 amps it would take a LONG time to get the voltage back up.  I guess we need details on how long they were charged and at what amperage.

I have a similar bank, 8 6v T125's so that is about 900 amps at 12v.  If the batteries were low that would take quite a charge to get them back up.

[RogerAS]

Brock,

Well, I'd say they were seeing about 40 amps (+ or - 5, via auto amp meter). The thing is it has been really hot here in Arkansas and I'm wondering if that's got something to do with the problem, however this has not been a problem in the past. We've been off grid for going on 5 years. I'm drving a 100 amp Mopar, externally regulated via resistance alternator, so the rate is constant. I've used this system all along. I also have 4 BP75watt PV's and a morningstar controller. I unhooked my wind system thinking maybe the blocking diode was shot. Maybe I should check out the solar controller.

About 3 weeks ago I did my monthly service. Topped up the acid with distilled water, or it was labeled so. I thought I was pretty cautious about the fill level, but maybe I put too much in. Think that could be it? I stopped at the ring, where I always filled to before, and none seemed to take much, maybe an ounce or so each.

Anyway I've NEVER had to run the system for more than 6 hours, but then again the voltage was never down to the inverter cut-off of 10.5 before. I'll know more when I get home tonight and read the voltage.

Thanks,

RogerAS

[brock]

I hope that it just needed a "good charging"  I know it takes a bit more to get them all the way back up after you add water, the more water the more of a charge to get it back up.  I did an EQ charge after adding water last month and it did sit a long time at 14.2v then finally popped up to 15.4 after 4 hours or so.  I am guessing that ahd something to do with adding water.  In any case once I got them fully charged they have been fine since comming back up to full quickly with just the solar.

[tecker]

  just a thing the bad batt has achance of comming back hot weather is also agood time for sulfated battery posts.

[RogerAS]

Hey All,

When I got home from work and checked the battery voltage was still at 13.75 after runing the frig and a few other lite loads all day. So I really don't expect there is a bad cell. I've begun to think the alternator has a need for a new set of brushes. I'm no alternator guru, but this unit has seen a year+ or service.

I again ran the charging system all nite, and again the voltage was hovering around 14V, but maybe a touch higher than the nite before. I'm not too worried about it any longer. I have a backup alternator and will mount it this weekend. I checked the post connections again, and there are all clean and tight. I've never had a corrosion or sulfation problem, and there appears to be none now.

It was well over 100 F here yesterday, AGAIN! I think this has a something to do with all this.

Thanks to all, both within this forum and privately.

RogerAS

[Gary D]

Roger, I'm no expert by any means. If you think about it, the hotter it is the more the fridge has to run, possibly lower heat exchange effeciency? A few extra amps a day tend to add up. Just a thought here. Not worth 2 cents tho... Gary D.