# flat battery



## metblue (Oct 9, 2006)

Hi,we have a 2000 autotrail mohican on a mercedes sprinter 313cdi. My problem is the vehicle battery goes flat within 3 days of it being parked up !! once started it the restarts no problem,leave it and bingo flat again.
I have checked everywhere i can think of and cannot for the love of me find where it is being drained from, nothing has been left on,there is no led for the alarm,no light in the engine bay,so where the beep beep is the power going ? I have even taken the battery off and given it a full charge,a local auto electrician tells me battery is good !!
Any advice would be much appreciated.cheers


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## GEOMAR (Mar 16, 2008)

*flatt battery*

is the switch for reversing camera switched on as the camera will still be using power even if ignition is switched off and reverse is not selected
GEOMAR


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## clive1821 (Mar 27, 2010)

out comes the test gear and have a look at the discharge on the battery..... it could be anything.... current meter in series with the battery and then a matter of pulling fuses until it the main discharge disappears.... sounds to me like we are looking for about 1 to 2 amps discharge if the battery is good and would take about 3 days to discharge.... sounds like a light is indeed left on or similar like the fridge .... radio or satellite receiver etc...


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## Techno100 (May 8, 2010)

Best to take the fence down and invite fellow campers in to have a butchers :wink:


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## rosalan (Aug 24, 2009)

My previous alarm system managed to drain the battery whatever I did.  
I am sure that you have made a diligent check of everything visible like cupboard lights. :roll: 
Your next move could be to isolate (disconect) the battery and check if it will still start the vehicle after 3 days then start removing fuses after checking which ones are still carrying a load with the ignition off. Eliminating circuits until you are left with the precious few possibilities.
There may be much better ways but I am not an electrician. :wink: 
Al;an


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## sideways (Jun 2, 2008)

This may be of no help to you but its worth checking,i have an 05 Sprinter, i had same problem and eventually found it by chance the red and blue heater knob controls a valve on the bulkhead under the bonnet, For some reason when you switch of this valve was remaining live and draining the battery, if i diconnected then reconnected the battery the valve was off until next time the ignition was switched on and then it remained live again. i guess its a relay somewhere. I cut the live to the valve and fitted an illuminated switch in the line mounted on the dash.as long as i switch off when parked i,ve never had a problem since.
Just one other point my fridge draws power unless the selector is off ie not left in the 12v or 2v0v position when parked.


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