Battery drain mistery? Alternator?

[nariusb]

Hi all,
I have a battery drain and it's big enough to lover voltage to below 11v over night for the car not to start.
I performed the bulb test by pulling all the fuses and relays under the hood and rear seat to no result - nothing registered. I do have an aftermarket amp but it's not the culprit.

Could it be shorted diodes in the alternator even though alternator tested OK?


Thanks

[Dave M]

Has the battery been drained recently, or otherwise 'abused' (trunk left open, extremely cold, short trips etc)? Even if you're not certain, it might be worthwhile to get it fully charged (if you already haven't) as vehicle charging systems are not designed to charge bateries, only maintain healthy ones.

I just went through this with a jetta. Tested it at night (12.7V), then again in the am (7-9V). Charged it, no more problems.

Good luck,

Dave

[BillionPa]

with my car i had to put a space heater pointing at the battery to warm it up, otherwise it went from completely charged to not being able to start the car in less than 10 mins.

once it was warm it was able to get charged completely.

[Mas (UK)]

after sitting for a few days while I drove around in my little runabout. So I took the battery out, recharged it overnight and put it back in the car ... only for it to go flat again a few days later. I suspected something was draining it because it can normally keep charge for weeks sitting in the car. Then it came to me. My little BMW torch in the glovebox stopped working a week or so before as its battery has died completely (the bulb's ok). And it was still plugged in it's socket in the glovebox. Took it out and no more drained battery problem. This little bugger was continuously trying to charge and draining the main battery. Might be worth checking yours.

Cheers,

Mas

[nariusb]

My battery is 5 months old, and I had it out and trickle charged but the drain off course is still there.
Can my after market amp draw current through the ground wire with positive disconnected, since that's how I had it when testing for draw?

And I'm still curious about the shorted diodes in alternator causing this.

[nariusb]

I pulled alternator today and the draw still the same. One good thing from all that I changed voltage regulator while I had it out.

I also completely disconnected my amplifier and head unit - still the draw was there.

So to sum up I pulled all the fuses and relays, disconnected my stereo system also alternator. It must be a short somewhere but why the fuses wouldn't find it?

[BillionPa]

how many mA is the draw?

[nariusb]

I had my multimeter setup on 10A and it blew a fuse. The test bulb is quite bright indicating much bigger draw then reg. 30-100 mA. When I turn the inside light ON the test bulb gets even brighter.

I do need to invest in a good Fluke DMM I guess.

[nariusb]

I redid the fuse pull one by one and did notice a slight but noticeable draw by fuse #22 ( Windshield wiper Cotrol (ADV), I pulled it and my windshield wipers/spray are functioning.
What could this be caused by?

I'll get the good multimeter and recheck exactly how much mA the difference is.

[nariusb]

I've got the amperage. With all fuses in it draws 0.18A and with fuse 22 removed it drops to 0.02.
Is 0.02 normal?
Where do I look for a short, guys, please help.