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-   -   Slow Drain on Battery (http://www.maxbimmer.com/forums/showthread.php?t=154617)

325ixE30 11-26-2012 07:13 PM

Slow Drain on Battery
 
Hi All,

I dont drive my car too often (live/work downtown) sometimes maybe once a week, sometimes less. About a month ago I replaced my battery. It was tested and they said it was gone, but weren't specific.

I bought a new battery and everything was fine as long as I drove it once a week.

I went to go start it tonight and the battery doesn't have enough to crank the engine, but has enough to work the radio and interior lights.

Very similar to what happened before I replaced my old battery.

My old battery wouldn't even start the car with jumper cables hooked up to another car.

I've checked all the interior/trunk lights to make sure nothing has been left on, but have found nothing.

Has anyone experienced this? Could it be the alternator?

adam325i 11-26-2012 07:54 PM

Soon as you got your new battery did you put it on a long slow charge before using it?

noid 11-26-2012 08:14 PM

Are you sure it is your battery and not your starter? More specifically your ground that allows for your starter to ground? To test this, take your negative jumper cable and clamp one end to the oil train plug and the other then to the steering rack.

I have had an alternator in my old e30 that would charge but not fast enough if at/around idle. To test this take a volt meter and check the voltage at your power lead at your battery while the car is on, you should see over 13v. It could possible that a diode has gone bad and it is drawing power even when the ignition is off. Thankfully Canadian tire tests alternators for free.

Have you checked the trunk light, glove box, trunk, and interior lights?

Other things to suspect:
Bad relays
Pinched wires

Also see this thread:
http://forums.pelicanparts.com/porsc...s-battery.html

325ixE30 11-27-2012 02:30 AM

Quote:

Originally Posted by adam325i (Post 1590584)
Soon as you got your new battery did you put it on a long slow charge before using it?

Got it fully charged and checked before I left the store.

325ixE30 11-27-2012 02:33 AM

Quote:

Originally Posted by noid (Post 1590588)
Are you sure it is your battery and not your starter? More specifically your ground that allows for your starter to ground? To test this, take your negative jumper cable and clamp one end to the oil train plug and the other then to the steering rack.

I have had an alternator in my old e30 that would charge but not fast enough if at/around idle. To test this take a volt meter and check the voltage at your power lead at your battery while the car is on, you should see over 13v. It could possible that a diode has gone bad and it is drawing power even when the ignition is off. Thankfully Canadian tire tests alternators for free.

Have you checked the trunk light, glove box, trunk, and interior lights?

Other things to suspect:
Bad relays
Pinched wires

Also see this thread:
http://forums.pelicanparts.com/porsc...s-battery.html

Its not the starter. Unfortunately I don't have any electronic testing devices.

The first thing I double and triple checked were all the interior/trunk/glove box lights.

cormier 11-27-2012 12:38 PM

Get a $20 multimeter -- it will make this process a lot simpler :)

It doesn't crank when boosted? Even when left to charge for a bit?

It could just be your alternator going slowly as mentioned... Or your battery draining slowly...

Try to get it started (roll start, jump, etc) and meter the battery. You'll be able to rule in / out alternator right away if the volts are staying constant or dropping.

When it's even running for a bit and then is shut off, meter again to check if your battery is holding charge.

May be worth investing in an on-car trickle charger to keep your battery nice when it's sitting for periods like that

everlast 11-28-2012 08:39 PM

I use a Battery Tender on my e30 that sits for days or weeks (or in the winter, months) and have had excellent success keeping the battery healthy that way.

325ixE30 11-28-2012 09:05 PM

Quote:

Originally Posted by cormier (Post 1590664)
Get a $20 multimeter -- it will make this process a lot simpler :)

It doesn't crank when boosted? Even when left to charge for a bit?

It could just be your alternator going slowly as mentioned... Or your battery draining slowly...

Try to get it started (roll start, jump, etc) and meter the battery. You'll be able to rule in / out alternator right away if the volts are staying constant or dropping.

When it's even running for a bit and then is shut off, meter again to check if your battery is holding charge.

May be worth investing in an on-car trickle charger to keep your battery nice when it's sitting for periods like that

I haven't tried to boost it with the new battery, but the old one did not crank even when left connected to the other car for 10 mins.

I'm going to take the battery in to where I bought it to get checked out and charged, but will need to give it a boost to get it there - lol!

:o(

TSI 11-28-2012 10:33 PM

Where are you located? I might be able to give you a hand with that...


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