# Engine battery flat but leisure battery fine?



## cairngorm (Nov 10, 2005)

I have owned my motorhome for one and a half years and on three separate occasions the engine battery has been flat and unable to start. On the first two occasions I was in a rush to get going and did not cheek the voltmeter in the van to see what was going on. The third time the the control panel was flashing charge required. The leisure battery seemed fine by the reading but the engine one was flat. Reconnected to the electricity and loo and behold ,the van started when I came back later on. We had Battery Master fitted by Van Bitzs and by my understanding of how it worked ,the engine battery would be left fully charged and the leisure battery would wind itself down.
On all three occasions the van was not connected to the electric ,but has been left unconnected before and not had a problem. Can anyone point me in the checks or tests that I can figure out what is wrong. Failing that could they please wave a magic wand and make sure that it never happens again. Cairngorm


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## DABurleigh (May 9, 2005)

Cairngorm,

From your post one cannot diagnose that anything is necessarily wrong with your Battery Mate, batteries, or van. It depends on infomation not known or offered.

I recommend begging, borrowing or buying a cheap multimeter and measuring the current draw on your batteries when everything is switched off (and at dusk if you also have a solar panel).

Dave


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## oldenstar (Nov 9, 2006)

I too have that set up, Van Bitz having fitted the Battery Master and a larger Leisure Battery, and when I go out and check the van after a week or two idle, it is always the vehicle battery which is lower.

I suppose that providing you have switched everything off in the habitation area there is no actual drain on the Leisure battery, whereas there are various items such as clocks, trackers etc taking some power from the main battery.

With the Battery Master however I can simply hook up and charge the main battery, which my van's setup would not do previously, avoiding the need to start the van for recharging.

It was not my understanding that the Battery Master would actually take power from the Leisure Battery to top up the vehicle battery without mains or engine power being used. I stand to be corrected on that by resident experts, or Eddie himself.
Paul


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## DABurleigh (May 9, 2005)

oldenstar said:


> It was not my understanding that the Battery Master would actually take power from the Leisure Battery to top up the vehicle battery without mains or engine power being used. I stand to be corrected on that by resident experts, or Eddie himself.
> Paul


Paul,

Yes, it will do that, if for any reason the vehicle battery drops to 0.5V less than the leisure battery.
http://www.motorhomefacts.com/ftopicp-264713.html#264713

Dave


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## cairngorm (Nov 10, 2005)

DABurleigh said:


> oldenstar said:
> 
> 
> > It was not my understanding that the Battery Master would actually take power from the Leisure Battery to top up the vehicle battery without mains or engine power being used. I stand to be corrected on that by resident experts, or Eddie himself.
> ...


So if there is a drain on the engine battery ,the leisure battery will eventually go flat as well.So if there is plenty of life in your leisure battery,then it should be possible to connect your jump leads to the engine battery and get it started. Although in my case when the RAC turned up to start me, his jump box was not strong enough to get me going. Had to connect the van to his van. Told me that this had never happened to him before. Cairngorm


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## teensvan (May 9, 2005)

Hi.

Your leisure batteries are constructed to give a small output 20 amps an hour over a long time where as a starter battery is designed to give a high output 450 amps + over a short time. You could end up with your leisure batteries nickered if you try and start your van off them.

stave & ain. -------------- teensvan.


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