Mercedes 300TD
The battery on this car is always on the verge of being flat 12.1 Volts. I have removed the battery several times and brought it up to 13V on a trickle charge but a week or so later it is down to to just above 12 volts.
The battery is new. and in good condition, I have ran my van on this battery and the battery remains at a constant 12.75 volts
I have had the car checked by a mercedes dealership, an auto electrical company, and another garage, all say the charging system is normal, non of these can come up with an answr!
I cannot find any substantial drain on the battery, with an amp meter attached I am getting 0.05A with the car locked or unlocked.
For instance, Today I swapped batteries with the van. The perfectly good van battery was at 12.75 at 9am, it is now at 7pm down to 12.42V, the car has not been started and theire is nothing switched on.
Something must be coming on to drain the power, but what ?
Now heres the wierd bit, went away on holiday for a fortnight, the battery was at 12.2v when we left and was at 12.1 v when we returned!
It is as if something only drains the battery when its above a certain charge level!
Any suggestions??
BTW It isn't the boot or the glove compartment, I removed these bulbs long ago!