Battery drain

[ederland]

My starter battery is being drained by .4amps and it is the fridge that is doing the draining. Why does the fridge run off the starter battery ? Is this normal? why not the leisure battery? I have had to get a start from the ferry company the last 3 times .The fridge works perfect, is it a bad earth? I am confused, please help somebody. My van is a Lunar roadstar 780 built 2005.

 

[Jimbohorlicks]

Hi
i don't think that a 0.4 volt drain will reduce your starter battery to such a point that it will not have enough amps to start the vehicle , unless that is the battery is not holding a charge anyway.I assume that the ferry starts your vehicle after the crossing -not before -if that's the case the fridge is not powered by the alternator because the engine is not running. The fridge would be off even though you have selected the 12 v for the fridge whilst you was motoring to the ferry.
I would have your cab battery checked.

best of luck:thumb:

 

[cmcardle75]

My starter battery is being drained by .4amps and it is the fridge that is doing the draining. Why does the fridge run off the starter battery ? Is this normal? why not the leisure battery? I have had to get a start from the ferry company the last 3 times .The fridge works perfect, is it a bad earth? I am confused, please help somebody. My van is a Lunar roadstar 780 built 2005.

It is quite normal for fridge 12V to be off engine battery. This is because it is only used for ignition (negligible usage) or cooling (engine running only). I suspect, though, that the fridge is not the problem, but you are using one of those inaccurate current meters that don't have a proper zero. You probably just have a bad batt
ery. You'll need a multimeter and someone who knows how to use it to investigate further.

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[sean n maggie]

i always thought the fridge only run when the engine was running,,therefore it wont be on when you are on the ferry,,,,think you need a check on your main battery to see if its holding a charge and check your alternator is charging at the right rate too..

 

[tonka]

Is it an Autotrail?? The system has a drain of .3 amps if you leave the psu switched on .

 

[sean n maggie]

Is it an Autotrail?? The system has a drain of .3 amps if you leave the psu switched on .

our psu turns off once i start the engine, only comes back on when i press power button and its an Autotrail...

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[TheBig1]

standard 3 way fridge wiring utilises a relay to prevent the engine battery draining with the engine off. if the fridge is drawing a current on 12v with engine off, check the relay

 

[Jaws]

As the big 1 says..
The fridge should draw NOTHING when the engine is not running

if the fridge is drawing anything then the relay is stuck on


A bit of maths
All ball park figures but close enough

Lets presume you have a fairly large healthy cab battery that is a 100aH

Lets say once it gets below 20% capacity it will stand no chance of starting the engine
So you have 80aH to play with. ( unless you have a traction battery in which case you can go much lower.. say down to 10 % )

At a .4 amp drain that battery will be down to below usability after just 8 days of the van sitting.

If you have an alarm fitted that will also be drawing current too.. So about a week and you aint going nowhere !

 

[hilldweller]

standard 3 way fridge wiring utilises a relay to prevent the engine battery draining with the engine off. if the fridge is drawing a current on 12v with engine off, check the relay

What about the interior light.

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[pappajohn]

if the fridge relay, with engine off, had jammed/welded closed you should see a drain of around 10amps from the starter battery.

thats why it only works with the engine running, otherwise the battery would be completely dead (as in destroyed) in around 8 to 10 hours

 

[TheCaller]

What about the interior light.

If it's like mine, the fridge interior light is wired to the leisure battery.