Stang Chik

Im having an issue with my battery. If I leave my car sitting for one day there is not enough juice to start it. I can run if for a half hour and it wont start, even if i charge the battery. I think somthing is drawing on the battery but shouldnt my alternator charge the battery while Im driving? What should I do first to diagnose?

50fiend

Make sure there's water in it...if that's possible...on some batteries you can't.

vfast

put a slow charge(overnite) then test the volts if ok put a load on it...my quess is you have a weak cell in it if it 3 yrs or older

VertStangGT86

Some of the cheaper batteries will go dead, as in the cell, if they've been discharged. They won't take a charge after that, also are you sure your alternator is fine? might wanna have that tested just in case. Get a new battery if charging doesn't work and if you still have a problem and your alternator is fine then you've got something drawing current elsewhere and you'll have to do some electrical troubleshooting.

Stang Chik

Ive been having this problem for a while. I got a new battery and its the same prob. I guess my next step is to check the alternator. The car sits in the garage most of the time.. so its not a huge issue.. but it pretty lousy that I have to deal with jumping the car when I do want to drive it.

619socalstang

you could have a bad ecm,(PUTER) had the same problem and it was the ecm, i hope for your sake it is not.

roundman

get the output of the alternator checked at a parts store. they can do it for you if you remove it from the car and some might be able to do it with it on the car. if the alternator is not the problem, then get a test light and check for a current draw with everything off. remove the negative battery terminal and hook up the test light between it and the battery negative post. if the light lights up, something is drawing current out of the battery. check the obvious things too, like the under hood light, hatch lite, dome lights, to make sure they are off when the hood is closed, etc. you don't have any stereo stuff installed that ain't powered by the ignition switch do you as this could be the source of the problem also. you want everything electrical to turn off when you turn off the key or else this can happen over and over.

VertStangGT86

The alternator comes out easily enough so just pull it out and take it to a parts store, I've had to do this before too. One place I went messed it up though and I ended up going through the whole alternator circut checking everything. Alternator could def be your problem if you havn't checked that out yet.

vfast

and if it is the alt..it's a great time to upgrade

nhdungeonracer

I had a car that, if it sat for more than a day, would have a dead battery. Looked and looked for what was drawing on the battery, and couldn't find anything, so figured it had to be the battery. Bought a new battery, and that very night, my wife went out to the car for something and noticed a tiny little light shining thru glove box door. Sure enough, the switch for the glove box light had moved just enough do that the door, even shut, wasn't shutting off the light, and that was why the battery would go dead. Fixed the switch, and no more dead battery Just wish she spotted it before I bought a new battery, but you know how women are