Draining a battery dead

[Rickomatic]

I am troubleshooting an electrical problem in my son's car. The car (a 90 Geo Prism) is draining the battery. The battery will be dead after about a month of normal use. I can charge it back up full and go through the cycle again. In January I replaced the alternator and the battery. I was not sure how many times I could drain the battery and then charge it before it would just quit taking a charge. This morning my son went out to go to school and the thing was dead again. I have noticed when the car is at an idle, the lights dim quite a bit and the car will sometimes stall. I tuned it up, and it seems to idle a little better, but the lights still are dimming. Any ideas to where I should look next.

 

[Rusted]

I vote for bad battery cables or other cables. I would start by removing the battery cables and replacing them if they are not in good shape. make sure the ends are clean, and whatever they bolt to is clean as well, so you have a good connection. Sounds like your alternator is having to "push" through dirty connections and not enough is getting through to keep the battery charged.

 

[Paudrhound]

If you put a stereo in, I would check in that area. That's where I found the short in my sons car.

 

[Shawn]

I went through the same problem with the in-laws car. We replaced the battery and the alternator. Turned out to be the starter... The starter still worked some what fine, every time you would try and start the car, it just didn't have the kick over that it should have. Turns out that the starter was slowly draining the battery as it sat.

FYI, it may or may not be, just sharing what happened to us.

 

[Rickomatic]

I will look at the cables. I have cleaned them on the battery, but I haven't followed them the entire way. The radio has been in the car for going on eight years, but a wiring could be loose. I have also wondered if the starter could draw even if it wasn't engaged. Again, one more thing to check. Thanks for the ideas.

 

[Webby]

Have you checked for a surface dischage or some little thing on all the time in the car you don't notice (ie: Small light).

 

[Tiny]

Have you checked for a surface dischage or some little thing on all the time in the car you don't notice (ie: Small light).

thats what happened to me, one stupid little light on my cd player was staying on and draining my battery so I smacked it and it turned off and its been fine ever since.

 

[nvrstuk]

Same thing happened to our eclipse, stalling, lights dimming, the whole bit. I replaced the alternator and it worked just fine. Could it be you bought a faulty alternator? Maybe charge up the battery and take it to Autozone to have them do the free diagnosis and at least eliminate the battery and alternator for sure.

 

[ace]

The vanity light in the glovebox in my wife's xj came loose on it's screws once, and moved so it wouldn't turn off. The battery would go dead if parked longer than overnight. What a pain to figure out

 

[burowyako]

I just recently replaced my battery with a red-top Optima battery. My old battery only lasted me about a year and I'm not sure why. What type of battery are you running?

 

[Rickomatic]

I just recently replaced my battery with a red-top Optima battery. My old battery only lasted me about a year and I'm not sure why. What type of battery are you running?

I let my son buy it, so it is one of those MaxLife walmart specials.

 

[Happy Joe]

Trouble shoot it thusly;
Verify that you have charging voltage when it is running (need a voltmeter ... harbor freight has cheapies that are entirely adequate.) If insufficient voltage is availiable to charge it, check all the cables and grounds (do not forget the engine to chasis grounds) then verify the wires going to the alternator. If the alternator is energised but does not generate suffucient charging voltage The problem is most likely the brushes or diodes.
If charging voltage is availiable at the battery, turn the engine off and disconnect one side of the battery, set your digital voltmeter to measure amperage at its highest range (hopefully more than 10 amps)connect one terminal of the dvm (digital volt meter) to the open battery terminal and the other to the battery cable that you removed. The meter should register a small (.25 amp or greater) drain (current flow). Remove the fuses one at a time and check the meter after removing each fuse. When you disconnect the fuse that is associated with the device causing the drain the drain will drop to zero (or very close). now figure out what is causing the problem in that circuit.
If the drain remains after all of the fuses have been removed; you will have to check other electrical items by disconnecting them one at a time (note; the computor (and clock) will have a very small amount of power going to it to keep its memory alive this will not drain the battery unless the vehicle is stored for a long time).
Auto parts stores make their money off of replacing parts and I have seen most people replace good alternators by letting those bozos tell them what is wrong.
From the symptoms above I would guess that you have insufficient charging voltage. (note; big stereos (or too many off road lights) can overwhelm small alternators. If the stereo (or lights) draws more than the alternator can supply the battery will discharge.
Enjoy!

 

[Rickomatic]

Happy Joe,
Thank you. That is one of the best electrical troubleshooting writeup I have seen. I have printed your reply and will start the troubleshooting now. Thanks again.