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Battery drain

2766 Views 7 Replies 8 Participants Last post by  marnaz
Hi can you suggest ways of tracing battery drain?
I have a starting battery (new) and two leisure batteries on my winnebago adventurer.
When parked in the drive if I dont leave a battery charger connected to the start battery it is flat in a couple of days.
The obvious I have checked, no lights etc on.
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Hello yam.
My old Winnebago used to drain half an amp per hour contstantly. Most was from the clock/alarm over the hob/cooker. But the radio and any alarms you have will also suck amps.

The only way is trial and error. Put an ammeter or lamp in line or series from the + post on the battery and the cable clamp to see what load you are drawing and then pull each chassis 12v fuse in turn until the light goes out or the ammeter shows zero.

get yourself a meter attach it in series from the battery to the positive lead and start pulling fuses/ turning things off until the meter shows no current drain

Ours used to drain the batteries as well, the quick fix is to turn the main battery switch off when you leave it, nothing should then be on any alarm should run off the engine battery.
We have a solar panel connected to the leisure batteries and a Battery Master (clever box of tricks), linking the leisure batteries to the engine battery, we now always have fully charged batteries.
I think there will always be a slight drain as there are so many circuits on an RV eg heating system with thermostat, tank level indicators, gas alarms etc and many other relays and sensors which remain on all the time, try switching off the batteries.

dangerous 8)
karlb was nearly right, but disconnect the battery NEGATIVE lead and put the meter in here, its safer. Then pull fuses one at a time until you find the culprit.

battery drain

My truck conversion has all sorts of silly gadgets (from its original life) which drain power. Being short of time I just fitted a battery isolation switch until I can find the time to track them all down and remove them.

Fitting a switch may also improve security

Cheers Joe
Battery Drain

In my past life I used to be an Auto electrician, With many types of vehicles were brought in with a 'mysterious ' Battery drain. Even with all the fuses pulled and seemingly everything isolated, still it was showing a discharge. Turned out the alternator diode pack can fail and allow a current to flow via the rotor to ground through the voltage regulator. If you disconnect the alternator and the drain goes you have the cause.
Hope this is useful for you its rare but can happen.
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