House Batteries are fully charged but acts like they are not

[Dow12]

I have a 2010 Class A Georgetown ForestRiver. Electrical works fine when plugged into shore power. When I took it off shorepower, generator would not start, steps would not come in, interior lights would not come on and jacks would not come up. Thinking the house batteries may be dead, I took the house batteries out and had the checked. Was told they were fully charged and was told everything was fine with the batteries. I put the house batteries back in and left the RV running for about 20 minutes. The Generator started and got the jacks up. Left generator running while I drove the RV for about an hour. When I stopped, I turned the general off, and just to see what happens I turned the interior lights on and they stayed on for about 5 minutes and then went off. Everything is acting like the house batteries are dead, but I just can't figure out why that is and what is wrong. The chassis battery starts the Rig up just fine, and not sure if that would have anything to do with it anyway.

Anyone have any suggestions on what could be my problem and how to fix? Thank you in advance

[down_home]

From what you have said I think it is the breakers or fusess or something has chewed the wires.

[wallynm]

you need to load test each battery to determine status

Dow12 wrote:
I have a 2010 Class A Georgetown ForestRiver. Electrical works fine when plugged into shore power. When I took it off shorepower, generator would not start, steps would not come in, interior lights would not come on and jacks would not come up. Thinking the house batteries may be dead, I took the house batteries out and had the checked. Was told they were fully charged and was told everything was fine with the batteries. I put the house batteries back in and left the RV running for about 20 minutes. The Generator started and got the jacks up. Left generator running while I drove the RV for about an hour. When I stopped, I turned the general off, and just to see what happens I turned the interior lights on and they stayed on for about 5 minutes and then went off. Everything is acting like the house batteries are dead, but I just can't figure out why that is and what is wrong. The chassis battery starts the Rig up just fine, and not sure if that would have anything to do with it anyway.

Anyone have any suggestions on what could be my problem and how to fix? Thank you in advance

[wa8yxm]

Atany auto parts store and most Auto Depts you can get a thing that looks like an old fashion ice pick with a wire haging out the transparant or tarnslucent handle An Automotive test light Way better than a volt meter for this. Two reasons.. It puts a load (About 1/2 amp) on the circuit v/s the tiny load (abou 1mA) of the meter. and instant indication no need to "Read the meter"

Clip to negative battry tip to positive LIGHT good. No light likely bulb needs reseating.

Move clip to unpainted frame part. LIght good. no light bad negative connection

Move out along the positive line with the tip. Touch each end of the battery cable and whatever it connects to each terminal

Do this unplugged

Problem exists between bright and dark.

[olfarmer]

I would check where the negative cable attaches to the chassis ground. I have had that connection get dirty or corroded. You might try bypassing the battery cut off switch. It sounds to me like you have a bad connection some where. Good luck finding where it is!!!

[enblethen]

Start from the batteries with a volt meter. follow through the system until the battery drops off. Circuit breakers are the small one inch cube style for 12 volt DC system.

[Matt_Colie]

Dow12,

What you are seeing is classic for a bad terminal .

The best way I know of to find this is with a test light.
This would be a very small (low drain/current) bulb with two wire leads. Attach one to the battery terminal and then walk the other away from then bank until it glows.

You problem can easily be as much in the positive side as the negative. Just leave the house lights on until they go dim and then start searching.

Best of Luck and good hunting.

Matt

[Dow12]

Thank you for the replies. The batteries are only 6 months old, cells are full and had not been dry. I had a load test done and it showed to hold the load. terminals are clean and were tight. Not sure about the circuit breaker for the batteries. I tried again and plugged into shore power. Took of shore power and turned house lights on --- once again, they stayed lit for about 3 minutes and went off again. If it was a circuit breaker, wouldn't it have stayed off from the prior time I did the same thing yesterday? Thanks again for all the suggestions.. I am stumped

[wa8yxm]

House battery disconnect.. The batteries (And a couple things that must have power) are on one side of the switch.. The stuff you say stops working on the other.

Alternative is a master fuse or circuit breaker on the house batteries.

Final possibility is a very bad connection.. (High resistance)

[Ed_Gee]

If connections are good, then it sounds to me like batteries are worn out ... no capacity to hold a good charge for more than a couple minutes. I assume if wet cells that water levels are good? Wonder how old those batteries are. I agree with previous poster... you need to have a decent load test made.

[ferndaleflyer]

Load test the batteries. Might show you something different

[naturist]

It seems that there is a mode of battery failure in which the battery will show the full 12.6+ volts of a full charge, and even be able to deliver a small amount of current for a short time before collapsing completely, only to show full charge moments after the load is removed.

I had the battery on my TT fail in this way. Meter checking voltage only showed full charge. But it would only keep a couple house lights on for a few minutes. Took it to one of the auto stores and their volt meter also showed full charge, but a load test revealed the truth: it had almost no capacity to deliver.

I wound up having to replace that battery. I still don't know how, exactly, it came to be in that state or what I could have done to prevent it.

[Dow12]

It has 2 12Volt batteries, I cleaned the terminals. I checked the battery shut off and still nothing.

[doxiemom11]

Do you have a battery shut-off for the house batteries that is not turned on?

[enblethen]

Bad connection on coach battery system
Verify voltage on each side of battery disconnect.
Check battery connections
Are these 12 volt batteries or 6 volters?