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Discussion Starter · #1 ·
Hi, looking for some help as I am starting to struggle with my motorhome.

The battery has been going flat after a couple of days, obviously something is draining it.

BUT today the battery is charged and the engine will not even turn over, looks like the battery is not connected (but it is)
When testing the battery its 12v when not connected and drops to 3v when connected

Please can someone give me any advice before I go crazy

Many thanks in advance
Paul
 

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Discussion Starter · #3 ·
Thanks, the engine seems to charge the battery when it was running, only when it was left for a couple of days, could this still be the alternator?
 

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No it's probably not the alt.

Far more likely just to be a duff battery - inability to hold charge is a classic sign and it's normally exasperated by cold weather

might want to look here

You could get a meter and check for battery drain - typically from a bodged bit of 'enthusiast wiring' that these vans suffer from - you can even check with a light bulb. But if there is any doubt about the battery, buy another.
 

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A 21w bulb fitted between battery positive and battery connection will show the current draw when nothing on the van is switched on, i.e. the drain when parked up.

There should only be a few milliwatts - not enough to even make the filament glow - if it does glow you have a problem.
 

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Discussion Starter · #6 ·
Hi Reg, The battery is only a few months old.

Could you explain checking the drain again please. I have a multimeter, do I put one end on the battery the other on ??

Thanks Reg
 

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Turn off ignition. Disconnect neutral off battery. Touch one prob on the cable u disconnected. Then touch the other prob to the stump on the battery. Flick multimeter to amps. See what reading u get. Then get someone to pull out a few fuses. When the figure drops to near zero u have found u battery drain.
It could also be a battery on its last legs though like previously stated.
 

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Hi, looking for some help as I am starting to struggle with my motorhome.

The battery has been going flat after a couple of days, obviously something is draining it.

BUT today the battery is charged and the engine will not even turn over, looks like the battery is not connected (but it is)
When testing the battery its 12v when not connected and drops to 3v when connected

Please can someone give me any advice before I go crazy

Many thanks in advance
Paul
Paul,

If you are using a multimeter across the battery poles and getting those reading then the battery is absolutely knackered.
A 12v battery at rest showing 12v is flat, trust me. A 12v battery has six 2.1v cells so a charged battery would be 12.6v.
By connecting it with no load if it's dropping to 3v then use it as a door stop.
What make is it Lion by any chance ?

Can you put a boost pack on it and get it going, at idle you should be getting 14.3v out of the alternator.
 

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Discussion Starter · #9 ·
Thanks for your help everyone, it was a Yuasa battery, got a new one and working ok, will spend some time working out where the drain is coming from
 
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