Electrical Drainage?!

Every year it seems like I have to buy a new battery for my stang. This is getting old cause these batteries are high quality and supposed to last for 3 years. I dont drive my fox often, its garaged most of the winter so I can understand how the battery would go dead but if I don't drive it for a month I've got to charge it before driving. The currently battery isn't even a year old yet. More like 8 months old and is currently getting charged in the garage as we speak. Yesterday I charged my car off a Buick for 30 minutes, cranks like low juice but no engaged to start up.

I had my subwoofers directly hooked up to the battery but because of this nuisence as of yesterday I've unplugged them.

Any ideas why my battery would be dieing out on me so quick?! Is there a short circuit in my electrical? I absolutely HATE electrical but will give my complete attention to you fellow car guru's if you can give me any insight.
  • Sponsors (?)

You need a digital multimeter that can read amps in DC voltage.

Unhook the neg wire off the battery and hook the meter up in series with the bat. You'll have one lead of the meter going to the battery terminal and the other lead going to the battery cable.

You will get a reading in DC amps. Ideally you want under 1Amp of current draw with everything off. Anything more than that and you have a drain somewhere and need to start troubleshooting.

If it's under 1A, then your alt is prob the culprit and should be tested
Radio shack has a few. Sometimes the cheap ones don't do Amps in DC current. Make sure it has this before you buy it.

I used to be an electrician, so i have one of those expensive ones that measures everything
If you do not start/drive it much, buy a battery tender and forget about it.

If you do have a drain, you will need to pull one fuse at a time to isolate it, also check the fuse links on the starter solenoid and see if you can narrow it down from there, I just went through all this and had a lot of creative wiring to correct from previous owners.

I like Irish's idea even if you do find the parasitic draw.
A floating charger can be had for cheap and is simply necessary on cars which are not started very often.

FWIW, if you find more than 100 mA (0.1 Amps) of draw, keep going till you find the issue. Even a draw of that size will create issues for a car that sits. If your meter acts up when you go to check current draw, remember that you probably need to repeg the positive lead.

Good luck.
I would like to add about the multimeter. If you bought one from autozone, if it was the actron model, I would HIGHLY recommend that you take it back and get a equus from csk. Dunno where you live but out here it is checker. Might be kragen or schucks if you have them.


Thats the meter I am referring to. I have used alot of meters from many different places over my years. Radioshack had decent meters, but this is much more geared toward automotive work. But if you can afford it do yourself a favor and buy a fluke. JMHO... but seriously who am I :D