Attention Sparkies: Leisure battery issue

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ForgeCorvus
Posts: 3277
Joined: Fri Feb 08, 2013 11:32 pm

Attention Sparkies: Leisure battery issue

Post by ForgeCorvus »

Short version of the story:
I had the camper plugged into the mains to run a dehumidifier.
Later I could hear an alarm and tracked it down to the CO detector in the camper, there was a strong smell also.
I found out the leisure battery was hot and I'm assuming outgassing. Disconnected it and put it outside.
It now has a definite bulge so I'm assuming its had it.

Now, I have a replacement but I don't want to fit it unless I can be sure that it won't get b*ggered up.
So I thought I'd ask you wise lot, how did my old battery die (it was quite old) and if it could be a fault with the system how do I find it and fix it?

Thanks folks
jennyjj01 wrote:"I'm not in the least bit worried because I'm prepared: Are you?"
Londonpreppy wrote: At its core all prepping is, is making sure you're not down to your last sheet of loo roll when you really need a poo.
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Yorkshire Andy
Posts: 9853
Joined: Thu Oct 03, 2013 4:06 pm

Re: Attention Sparkies: Leisure battery issue

Post by Yorkshire Andy »

ForgeCorvus wrote: Tue Mar 17, 2026 9:43 pm Short version of the story:
I had the camper plugged into the mains to run a dehumidifier.
Later I could hear an alarm and tracked it down to the CO detector in the camper, there was a strong smell also.
I found out the leisure battery was hot and I'm assuming outgassing. Disconnected it and put it outside.
It now has a definite bulge so I'm assuming its had it.

Now, I have a replacement but I don't want to fit it unless I can be sure that it won't get b*ggered up.
So I thought I'd ask you wise lot, how did my old battery die (it was quite old) and if it could be a fault with the system how do I find it and fix it?

Thanks folks

It's buggered lol the gas is hydrogen sulphide

Over charging

Over heating

Or internal battery failure

Are the three main issues

Put the new battery on and use a multimeter to check the charger output periodically anything higher than 14.7 volts when Charging is too high you'll often find dumb caravan charger / power supply units are around 13v

You'll probably find the old battery has got low on electrolite


Ps make sure the units vell vented the gas is explosive
If your roughing it, Your doing it wrong ;)

Lack of planning on your part doesn't make it an emergency on mine
GeraldTheBonzai
Posts: 307
Joined: Fri Oct 08, 2021 7:52 pm

Re: Attention Sparkies: Leisure battery issue

Post by GeraldTheBonzai »

What type of battery? AGM or lithium? Could be multiple reasons. If the battery is really old then it could be sulfation or an internal short.

I would work on the principle that the battery is shot. Check you charger to see if the settings are right and it's not over voltage.

Would definitely leave it outside. When you say hot, you mean warm to touch or "feck that's hot!"
ForgeCorvus
Posts: 3277
Joined: Fri Feb 08, 2013 11:32 pm

Re: Attention Sparkies: Leisure battery issue

Post by ForgeCorvus »

Oh I know the old battery is fked... I believe thats the correct technical term?

Hot as in "can't hold it"* not hot as in melting

I'll dig out the meter..... As long as the charge output stays under 14.7 alls good with the system?





* I trained as a blacksmith and welder, my idea of to hot to handle is probably a bit more then most
jennyjj01 wrote:"I'm not in the least bit worried because I'm prepared: Are you?"
Londonpreppy wrote: At its core all prepping is, is making sure you're not down to your last sheet of loo roll when you really need a poo.
"All Things Strive" Gd Tak 'Gar
GeraldTheBonzai
Posts: 307
Joined: Fri Oct 08, 2021 7:52 pm

Re: Attention Sparkies: Leisure battery issue

Post by GeraldTheBonzai »

ForgeCorvus wrote: Tue Mar 17, 2026 10:06 pm

I'll dig out the meter..... As long as the charge output stays under 14.7 alls good with the system?
It really depends on the type of battery chemistry. AGM are different to lead acid, and both are different to LiFePO4. Look to see what the battery type is, then look up the Absorption / Bulk voltage. Your charge doesnt want to charge above that. If your charge can charge different types, then make sure the correct type is selected.
Peter
Posts: 266
Joined: Wed Mar 01, 2023 4:21 pm
Location: West Midlands

Re: Attention Sparkies: Leisure battery issue

Post by Peter »

I had a vehicle parked long term using a charger/maintainer, the battery did not overheat but was still cooked/fkd.

I replaced the charger/maintainer with a modern CTEK MXS 5.0 (the dogs do-dars), not on permanent I use a timer
just for a few hours (4 or 5) .

With Camper vans with a built in charger, normally charge goes to the vehicle battery and it uses a relay to feed the
leisure battery only when the engine is running, (triggered by ignition switch) If you’re using the campers 240v system
for the dehumidifier switch off thcharger (bottom of wardrobe ?), or use an ordinary extension lead to save messing.

Hope this helps.