My battery will go dead if connected to my car in less than a day if its not getting recharged by the alternator. I have tried 3 or 4 batteries and 2 different alternators (1 brand new) and still I have this problem. I am thinking something must be drawing current when the car is off and draining the battery dead. I need to know the best way of checking this and finding out exactly where the current is being drawn from. Thanks!

 

All you do is disconnect the neg. battery cable. Then with a multimeter you switch it to read amps and touch the neg battery cable with one prong and the battery terminal with the other... in effect making a bridge within the connection. I believe anything over .05 amp draw is gonna drain a battery if I remember correctly. But basically what youll do is once you bridge the connection with your multimeter, go and start pulling fuses till you see the amps drop and youll find the circuit that is at fault.

 

Thanks for the reply....I had heard of something like that before, but couldnt remember exactly how to do it. How do I know what fuses control what, would that info be in a haynes manual or something?

 

You could find it in Haynes probably but there should be a diagram on the underside/inside of the fuse box lid.

 

what set of fuses are you referring too........the ones in the engine bay or the ones inside.....or should I check all of em?

 

Disconnect the ground and bridge the ground terminal on the battery to the ground cable with the multimeter set to read current. If it's not an auto adjusting one set it to milliamps. That will tell you if there is in fact a current draw. If there is, start with the positive battery terminals in the little red case. Remove each one until the draw disappears. Then trace that circuit and find out where it is shorted or grounded or whatever it may be. I went through this before but it turned out to be a bad battery. There is always a minute amount of current draw on the battery but like somebody above said, it has to be significant to kill a battery.

 

turns out my manual fan switch was drawing some amperage......but their is still a .068 amp draw. When I take out my power accesories fuse this draw is gone. What all does the power accesories control? I was monitoring the voltage also on my battery and it is definately still dropping in volts as it sits there (when connected to the car)

 

It varies from car to car if you've added anything, but typical suspects would be radar detectors, clocks, car stereos/amplifiers, alarms, lighting, etc. You'd need to locate the power source for each and unplug them one at a time...hopefully each one is fused separately...makes it easier.

 

Checking for shorts to ground is pointless. A short to ground will blow any fuse.

A bad power window module made my car draw enough to kill the battery.

I prefer a clamp on multimeter to read the DC current as putting one inline kinda sucks.

 

That's an easy assumption to make, but not entirely accurate...lots of wires can be shorted to ground and not blow a fuse. +12V to ground will, but not all wires are power and some things like a sensor or other wires can just increase current draw at times when they're not supposed to be active.

 

Well I dont have anything afterfmarket really...(electrical wise) I disconnected my manual fan switch and I have stock stereo and stock alarm. I did however unplug the sensor for the stock alarm, maybe I will check into that. Also, my windows are seriously dragging ***....to the point they wont hardly go up at all.....could be that the battery is low, but man they are friggin moving slow. I guess for the time being I will just take out the fuse when I leave it sit for any period of a time. I think once I do get this taken care of I am gonna buy a fresh new battery and hopefully my electrical woes will be gone.

 

Ok, I narrowed it down to the stock AC Delco cd player. When it is plugged in and the car is off I am getting a .068-.070 amperage draw on the battery. When I unplug the cd player it goes down to virtually 0. I did have my manual fan switch wired into the power source for the cd player, but it has been removed and the wire is taped up and secure. About a year ago I had an aftermarket CD player in their, but after about 3 months I took it out and put the stock unit back in. Does anyone know why my cd player could be draining on the battery? Btw the cd player works perfectly fine and I couldnt find anything wrong with it or the wires on the connection in the back. Now I am stumped, anyone have any suggestions?

 

The question now is if that is a reasonable amount of draw for it or not...hopefully somebody knows what it should be, or can check theirs. That doesn't sound like a lot to me...my alarm draws way more than that and still lasts about 2 weeks without being started. Once a battery is completely drained one time, I've never had good luck with recharging and getting them to recover...I always just replace them instead. I bought a red-top optima the last time and haven't had a problem since.