What Size Leisure Battery

Hi
I've got a 2002 Symbol which runs an Eberspacher and Truma heater.
The problem is that I only wild camp and I want to be able to run the Eberspacher for 2 lots of 30 minutes each day (morning and evening)
Currently I have an 85 amp leisure battery and it's not keeping up. Neither of the heaters now work as the voltage is down to 12.63 volts.
Any good suggestions please?

Thanks

I assume your leisure battery is under the drivers seat. You cannot fit a larger battery under there (I did find a 90amp but that isn't going to make any difference. You could consider putting a second battery under the passenger seat or of course have a solar panel on the roof to keep your battery topped up. At 12.63 v your battery sounds OK. As far as I can make out the problem should not arise above 10.5v.

These heaters need a good high voltage to start.Your battery is good,but not good enough. Maybe.
Try running the engine for a few mins before .
If this does not work consider a newer larger capacity battery or two.

Regards

Micky

Got 2 leisure batteries under my drivers seat...more or less same van I think,

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Tim.

I've tried running the vehicle beforehand but it makes no difference. What is a good high voltage? I've no idea what voltages are need. All I know is that it's a 12 v battery and the heaterscurrently will not run with 12.9v. What is the minumum needed do you think?
The space under the drivers seat won't hold two batteries but perhaps I could fit a single much larger battery? what are the maximum sizes do you know?

I have been thinking of fitting an extra battery in the boxed in area under the off side rear seat. There is plenty of room. I was thinking of making a battery base plate out of aluminium angle.

12.9v is enough to start the eber, provided the connections/wire size can pass the necessary current. I have had trouble before with ebers/webasto heaters starting due to poor connection through blade fuses which suffer corrosion, pull the fuses and replace, may work .

I have the same problem with an Eberspatcher in a Topaz. I find I need to start the engine and keep it running until the start routine of the heater is completed, about 3 to 4 minutes. It will then run normally. Without the engine I can see a significant drop in the battery voltage which means it is failing to deliver the necessary amperage at the requires voltage. The brains of the unit then registers a "low voltage cutout".  Bottom line is,  the battery is showing classic signs of failing. Still good enough for light loads, but not up to the load required by the glow plug in the heater.

We have a second battery under the passengers seat, and do a lot of wild camping all year round without any problems, in our boxer based Rambler