Battery Charging

[Bill Lampkin]

Just got back from our MH storage. Its been at least two weeks since I ran the genny. Not plugged in while in storage, and stored under an awning so no solar (original 100w panel). Went to check on the batteries. Xantrex 2512 inverter. Xantrex panel said house batteries were at 50% charge. Aladdin said house battery voltage was 12.3v. So I fired up the generator. Amps started around 25 and quickly (2min) went down to 7 amps. Xantrex panel charge was rising (53%). After a few minutes, Xantrex panel read 100% charge, Aladdin said 13.4v. I turned on both heat pumps to load the gen and let it run for an hour.

I tried to get the output of the charger up, so I cycled the AC power to the Xantrex a couple of times. No change in amps (7) or charge (100%). After an hour, all readings the same (7a, 100% charge, 13.4v)

Am I seeing a surface charge on the batteries or what is going on?

Next time I will take a voltmeter and will check the battery terminal voltage before I close the disconnect switches and  operate the remote locks.

I'm

[Gerald Farris]

Bill,
It sounds like you have a defective (shorted) battery temp sensor that is telling the inverter that the batteries are hot and therefore the inverter reduces the charging amperage to protect the batteries, and if so you can unplug it from the inverter to get the inverter to fully charge the batteries. If it is very cold there, the batteries will not take a good charge but the charging voltage should be above 13.4. What is the outside temperature there?

Gerald

[Bill Lampkin]

Thanks Gerald, Pretty cold here in N CA-was 70 here yesterday, 75 next week. Why would charge level start at 50% and go to 100% within minutes?

On our trip this summer, while boondocking for the apoceclipse in Oregon, the aladdin said the charge rate was 100a, then decreasing as I ran the generator to charge.

Like I said, I think I'll verify the actual bat voltage w/my meter before closing the bat disconnect switches the next time I'm at the storage yard. I have new (this summer) GC4 batteries.

[Gerald Farris]

Bill,
Did you check to see if you have a battery temp sensor, and if you do, did you unplug it from the inverter? A shorted battery temp sensor can cause charging problems like the ones you experienced.

Gerald

[Bill Lampkin]

thanks Gerald, i'll give the temp sensor a look next time I'm out there. Do you know what the nominal resistance of the sensor should be?

[Gerald Farris]

Bill,
No I do not, but I just unplug the temp sensor from the inverter, and if that fixes the charging issues, I know that it is bad.

Gerald

[Andrew Bruemmer]

This forum is great!!  We purchased our 2002 Contessa mid last year.  It's been in the shop for a few months to get some things worked on.  One issue is that I had no AC output when unplugged, thought it may be bad transformer/converter.  The batteries were all new when we bought it.  Stopped by the shop today for an update and they said the AC issue was that the the converter doesn't kick in when the batteries aren't charged enough.  So I was thinking ok, why wouldn't the batteries be charged as it was plugged in while we were using it but still had to AC out when I tested it unplugged.  This post made me realize the likely issue.  We were getting battery temp alarms but it was summer so I thought ok and just cleared it when it happened.  Didn't know the batteries wouldn't charge when that happens.  When I get the unit back I'll unplug that temp sensor if I'm still getting the alarm and see if I can replace it.