Causes of battery drains 2004 Mini Cooper
Discussion
Does anyone have any experience tracing battery drain issues?
History my Mrs mini 18months ago had alternator / regulator issue that took local garage plus BMW an age to sort, it initially had a new battery - didn’t fix it, had a new alternator - didn’t fix it, had a new power steering pump didn’t fix it. Had a 2nd new alternator - that fixed it.
Roll on 18th months and suddenly flat battery. Charged battery assuming mrs left the lights on, car fine for two weeks then dead again when she’d been away in it RAC out and diagnose faulty battery. Battery under warrantee so I got a new one fitted it and car fine for 3 weeks. Then dead again.
So today I decided to have a look myself and do draw down test pulling fuses. So car parked draws (excuse units probably wrong) 400ma (4.0 on multi meter), this has got to be too high Googling mini forums say normals 200 ish depending on spec. I start pulling fuses and relays in fuse box under bonnet no change on any. Start pulling passenger foot well ones based on other google searches only on to make a difference is the car alarm this drops draw to 350ma (3.5 on multimeter).
A friend who’s a mechanic suggested it’s another duff alternator so I pull the black plug on the regulator no change still on 350 now it’s got no alarm fuse. I can’t access the big red bolt on cable, so donI need to get this disconnected to test it, fully if so any access tips?
Any other suggestions - I’ve not done every last fuse in passenger well but had enough for tonight.
History my Mrs mini 18months ago had alternator / regulator issue that took local garage plus BMW an age to sort, it initially had a new battery - didn’t fix it, had a new alternator - didn’t fix it, had a new power steering pump didn’t fix it. Had a 2nd new alternator - that fixed it.
Roll on 18th months and suddenly flat battery. Charged battery assuming mrs left the lights on, car fine for two weeks then dead again when she’d been away in it RAC out and diagnose faulty battery. Battery under warrantee so I got a new one fitted it and car fine for 3 weeks. Then dead again.
So today I decided to have a look myself and do draw down test pulling fuses. So car parked draws (excuse units probably wrong) 400ma (4.0 on multi meter), this has got to be too high Googling mini forums say normals 200 ish depending on spec. I start pulling fuses and relays in fuse box under bonnet no change on any. Start pulling passenger foot well ones based on other google searches only on to make a difference is the car alarm this drops draw to 350ma (3.5 on multimeter).
A friend who’s a mechanic suggested it’s another duff alternator so I pull the black plug on the regulator no change still on 350 now it’s got no alarm fuse. I can’t access the big red bolt on cable, so donI need to get this disconnected to test it, fully if so any access tips?
Any other suggestions - I’ve not done every last fuse in passenger well but had enough for tonight.
Mr Ralph Jolly said:
How often and long is the vehicle being driven. Not sure of modern alternator/battery tech but I still work on the principle each start needs 10 mins of run time to put the charge back in.
It’s not that, the RAC call out was the morning after it had been driven from Oxford to Canterbury, voltage with engine running is a steady 14.5v so when running it’s charging fine.Problem is the draw is too high when parked up. With alarm disabled there shouldn’t really be any significant draw but there is something drawing 7 x more than the alarm system I can’t seem to get rid of.
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