Batteries are very hot....

cadman_ks · 04-23-2022, 09:12 AM

Took our new 2021 37MDQS out for the first time this weekend. When I would come and go out of the camper, I noticed that there was something that smelled hot but I couldn't put my finger on it.

This morning, I had to get the smoker out of the front compartment, and when I opened up the front door I had the a whiff of something that was incredibly hot. Checking into it more, I found out that our batteries were so hot that you couldn't touch them.

What causes the batteries to get that hot?

I immediately turned off the breaker for the converter, and after a period of time, the batteries did cool down but they're still pretty warm. After about another hour the battery is losing power, which I would expect because we have things running on 12 volt power. But now I'm leery of turning the converter back on and charging the batteries back up. It is almost like the converter overcharged the batteries and didn't stop when they got to voltage.

Has anyone else experienced this? In our last two fifth wheels, we had totally enclosed batteries in cases, and I don't think that they ever got this hot that I noticed.

Is there anything that I should be looking for or testing on the converter side???

Grumpy · 04-23-2022, 09:29 AM

Are they full of water? Could also be a bad battery (shorted internally) that is not charging so charger keeps trying.

TWP723 · 04-23-2022, 09:50 AM

Not enough water in them or could be the converter maybe.

cadman_ks · 04-23-2022, 11:04 AM

These are Interstate sealed batteries, so I can't check them for water. They are also only 4 months old too, and have not been thru many charge cycles either, so not that much water should be out of them.

I don't have my meter with me, but when we get home, I'll need to see what kind of power the converter is outputting...

**JFlightRisk** · 04-23-2022, 11:11 AM

Are the cables connected the right way?

cadman_ks · 04-23-2022, 11:22 AM

Quote:

Originally Posted by JFlightRisk

Are the cables connected the right way?

Good question, I think so. All of the positives are together, and all the negatives are together...

Grumpy · 04-23-2022, 11:24 AM

Quote:

Originally Posted by cadman_ks

They are also only 4 months old too, and have not been thru many charge cycles either, .

Could still have an internal short. Batteries go bad all the time, no matter what the age.

cadman_ks · 04-23-2022, 11:27 AM

UPDATE: Something is definitely pulling a LOT of power on the batteries. I have had everything 12 volt related turned off in the camper now for about 3 hours, and the batteries are still pretty warm to the touch. At this point they have not been charged in 3 hours and nothing should be pulling anything on them and yet they are still warm. The only other thing that I could think of, that might be pulling power, was the brakes, like the emergency switch had been tripped, and that doesn't appear to be the case either.

I thought maybe the inverter was powering the fridge, but I looked and the inverter is in bypass mode, which is the mode I would expect it to be in, since we are hooked up to shore power.

Also, I checked the battery cables, and the battery themselves are not hot at all, so it's like no power is going out of the batteries at this point either...

cadman_ks · 04-23-2022, 11:28 AM

Quote:

Originally Posted by Grumpy

Could still have an internal short. Batteries go bad all the time, no matter what the age.

This is actually what I'm thinking could be the problem with the batteries. I'll have to have them checked independently when we get home...

mini4mw · 04-23-2022, 11:32 AM

Short, bad battery, bad converter (or water but they are sealed so..)

If its not hot with the converter off, sounds like converter or battery issue and not a short.

Sounds like you have two batteries so if you turn it on I'd connect up just one battery at a time and see if one experiences the issue and the other does not. One battery has the issue, you found your problem. Both batteries having the issue, better chance its upstream like the converter unless both batteries are bad.

Any heavy 12v draw that could be on? High amp throughput could be issue too, but that should trip a breaker or an issue show up somewhere else.

cadman_ks · 04-23-2022, 12:49 PM

Quote:

Originally Posted by mini4mw

Short, bad battery, bad converter (or water but they are sealed so..)

If its not hot with the converter off, sounds like converter or battery issue and not a short.

Sounds like you have two batteries so if you turn it on I'd connect up just one battery at a time and see if one experiences the issue and the other does not. One battery has the issue, you found your problem. Both batteries having the issue, better chance its upstream like the converter unless both batteries are bad.

Any heavy 12v draw that could be on? High amp throughput could be issue too, but that should trip a breaker or an issue show up somewhere else.

Yeah, that's my next step while we're out camping. Take I e battery off at a time and see if one gets hot.

Thanks to everyone for the help and ideas!!!

Yooper906 · 04-23-2022, 01:04 PM

Quote:

Originally Posted by cadman_ks

The only other thing that I could think of, that might be pulling power, was the brakes, like the emergency switch had been tripped, and that doesn't appear to be the case either.

.

I would recheck your breakaway cable and plug again. Just to be sure.
Unplugged, they draw a lot of amps.

cadman_ks · 04-23-2022, 01:13 PM

Quote:

Originally Posted by Yooper906

I would recheck your breakaway cable and plug again. Just to be sure.
Unplugged, they draw a lot of amps.

Thanks for the tip! I did check that AND the brakes, and the break away is solid, and brakes are not hot, so I'm pretty confident it's not that...

Yooper906 · 04-23-2022, 01:21 PM

Quote:

Originally Posted by cadman_ks

Thanks for the tip! I did check that AND the brakes, and the break away is solid, and brakes are not hot, so I'm pretty confident it's not that...

That'ts good. Just an idea.

kirkelli · 04-23-2022, 01:46 PM

if the battery cables are cooler to the touch than the batteries, you can rule out load issues and isolate the problem to one or more of your batteries. I had an Interstate go bad 3 months after purchase. Put each battery on a load test to determine which ones are bad..

cadman_ks · 04-23-2022, 02:36 PM

First battery isolated, and I had a 50/50 chance, and after about 30 minutes of charging, it was HOT!! Switched to the other battery to see if it does the same thing. If it does, there's something wrong with the converter....

GHen · 04-23-2022, 02:40 PM

I agree with above, a heavy load would warm the cables up, low water, overcharging or battery short would cause the battery to get hot.

Wire up one battery at a time and test it that way.

The “free” interstate Marine/rv batteries you get with a new RV are a cheap battery to begin with and may be having an issue. I have interstate 6v CG2 deep cycles that are great.

cadman_ks · 04-23-2022, 04:05 PM

The second battery isolated now, and it's getting warm, because it needs to charge hard because it was being pulled down by the bad battery.

I feel pretty confident that one battery has dropped a cell. I'll have that battery tested, and see what happens.

THANKS TO EVERYONE FOR THE HELP!!! This is what makes this community GREAT!!!

GHen · 04-23-2022, 05:52 PM

How old is the good one?

Remember to match batteries, same year, size, capacity etc…
You may need to replace both. The system will only charge up to the weakest battery capacity.

When I first added a second battery, I kept it separate with a A, B, Both, NONE switch. Now they are all matched.

cadman_ks · 04-23-2022, 05:58 PM

Quote:

Originally Posted by GHen

How old is the good one?

Remember to match batteries, same year, size, capacity etc…
You may need to replace both. The system will only charge up to the weakest battery capacity.

When I first added a second battery, I kept it separate with a A, B, Both, NONE switch. Now they are all matched.

They are both the same age, and they are only 5 months old. This is a brand new unit...

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