Battery Overheating

[Killy]

First time out this year on July 4th. Whilst connected to EHU after a while we could smell the classic rotten egg smell, Traced it to the Vehicle battery that is a three year old Yuasa starter battery. It was pretty hot so I disconnected the EHU and vented the cab. I’ve now put in a new battery but I’m concerned about the possible cause. I’ve a solar panel and use a battery master to top up the vehicle battery. How can I check the charger isn’t over charging ie what should the voltage be measuring across the battery terminals when being charged? The hab battery was fine. The charger is a Nordelettronica NE287.

TIA

 

[berni109]

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[Raul]

Let it cool and measure the voltage after a hr or so. If reads above 12,8v the battery is still good, you just have gave it a good equalising charge, and probably desulphated the plates, if water levels are good. That means your charger is set to high or gone south. If voltage is low, below 10,5v, then it dropped at least one cell, the battery is at fault, not the charger.

 

[Gromett]

I personally wouldn't risk it. Once a battery has cooked badly enough to smell like that I am of the opinion your £20K+ motorhome and your health is worth more than the risk of a £120 battery.

However, I would check your solar regulator and battery charger to make sure they are not over charging the batteries and will cause the same to happen on the replacements.

 

[Lenny HB]

Agree with Gromett don't mess about fit a new battery then check the charging voltage from both your mains charger and solar it shouldn't be over 14.4v.

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[Killy]

Thanks all. Greatly appreciated, I did change the battery for a new one I’ll check the voltages and see how it looks. As the Hab battery is fine I think it may be a bad battery.
Is it possible to have a charger that also automatically looks after both batteries from the solar. I’d like a tidier more advanced solution that also monitors battery temperatures as well. I’d probably also change the solar regulator as well to the same brand to get a complete integrated solution. I’m a bit spooked by this as we could have been out all day and then returned to a pretty dangerous situation.

 

[Lenny HB]

CBE CSB-2 Solar split charge relay or a Batterymaster. They top the starter battery up with a trickle charge from the leisure battery.
They work slightly differently but with similar results.
The CSB-2 switches on to charge the Starter battery when the leisure battery is at or over 13.6v and switches off at 12.6v it can charge at a max of 4 amps.
The Battery master will charge the starter battery when the leisure battery voltage is 0.75v higher than the starter battery with a max current of 1.1 amps.

I've been using the CBS-2 on my last two vans without any problems. the CBS-2 is under £25 the Batterymaster around £65.

 

[two]

From what you say, it seems that the mains charger charges both habitation and starter batteries simultaneously. I don't suppose that the regime used for the vehicle/starter side is very sophisticated and may 'cook' a failing battery. If you have a BatteryMaster as well, you shouldn't need the mains-supplied charge. The BatteryMaster is only a trickle charge but is all that should be needed. You should be fine for the moment, with a new battery, but I'd look to disconnect the leads coming directly from the charger.