Ideas Why Battery is Going Dead

[CupCak3]

I have a, ?01 Sunfire with ~130k miles on it. Recently, if my car has been sitting a couple days, I need to jump my car to get it started. The batter is only ~2 years old. Could something in my car be slowly draining my battery? I installed a new head unit several months ago with no problems. I?m going to get the battery tested tonight to see if it?s going bad, but wanted to get some ideas beforehand.

Thanks!

 

[desy]

Even if the battery is only a couple yrs old you could have permanently damaaged it if you let it go completely dead in wintertime.
the battery could be going bad and lots have diminishing warranties to cover that

 

[jtvang125]

Have them test the alternator too. It could be on its way out and not charging your battery completely.

 

[herrjimbo]

in my younger days, i've had starters drain batteries. they still started the car fine, but there was a short in them, hence draining the battery. i dunno if autozone could check for that. should be able to via the cables.

 

[CupCak3]

The battery and the alternator tested fine. I've been doing some reading online and need to do some testing over the key-off current draw from my battery. This could be a big PITA. I guess I'll start pulling fuses and then relays until I find what's the cause! Will post back later when am home from business and am able to do some more work.

 

[brblx]

if the battery tests fine with a conductance tester and the alt is putting out normal voltage (13.8+), it's probably a parasitic draw. it's now that hard to check for, just disconnect the negative terminal and put a multimeter in series. if there's a significant draw after the car has been off for a few minutes, just start pulling fuses one at a time until the meter reading drops.

it's probably something silly like a glove box or other interior light.

 

[CupCak3]

Originally posted by: brblx
if the battery tests fine with a conductance tester and the alt is putting out normal voltage (13.8+), it's probably a parasitic draw. it's now that hard to check for, just disconnect the negative terminal and put a multimeter in series. if there's a significant draw after the car has been off for a few minutes, just start pulling fuses one at a time until the meter reading drops.

it's probably something silly like a glove box or other interior light.

My hope is that its something silly like that but I'm thinking it has to do with the harness or wires of my head unit. After a bit of thought, i believe the problem started after I added my antenna adapter and shoved the HU back in the harness. If that is the case, i'm REALLY hoping I don't have to tear into the dash.

 

[brblx]

what all did you install? just an aftermarket headunit?

i don't see how that could cause the problem, so long as it's turning off when the car is off (proper switched power connection). there has to be a load somewhere that's consuming power. just having, say, a broken or shorted wire isn't going to cause a problem with draw. well, unless you shorted something to power, but that's a longshot.

let us know what kind of draw you have when you test. if the battery is going dead in a couple of days, i would expect to see something pretty significant (more than an amp).

 

[CupCak3]

Originally posted by: brblx
what all did you install? just an aftermarket headunit?

i don't see how that could cause the problem, so long as it's turning off when the car is off (proper switched power connection). there has to be a load somewhere that's consuming power. just having, say, a broken or shorted wire isn't going to cause a problem with draw. well, unless you shorted something to power, but that's a longshot.

let us know what kind of draw you have when you test. if the battery is going dead in a couple of days, i would expect to see something pretty significant (more than an amp).

That is all I have currently installed but amp will be following as soon as I figure out this problem.

The HU actually isn't on a switched connection. I have to manually turn it off after every time I turn off the car (thought that I going to change soon... finally bought some wire and a spade fuse tap connector to pull off a switched fuse). I'm doubting it has to do with the switch since I had the initial HU install complete for about 2 months before this problem started up... I'm just tired of turning the damn thing off. Also, when I've pulled the HU out after a a period of no usage, the case was cool to the touch. It get quite hot when powered on. Though I'm definately not 100% ruling this out yet...

I'll be sure to post back numbers. From what I've read so far, my car should pull .15-.3 amps with key-off.

Thanks for the help brblx!

 

[fleabag]

It's possible that the OP does too much city driving and doesn't let the battery get charged enough. I had a similar issue with an LS400's battery where despite the fact that I drove on the highway after the battery being dead and boosted, I found the car was dead weeks later. So what I did was hook it up to a battery charger and fully charged/topped off the battery and now even though the car has been sitting for 3 months, the battery still has some sort of charge. It's definitely useful to have a battery charger because driving it around sometimes isn't enough to fully charge it especially after being empty.

Forgot to mention, make sure when the battery is being charged that you don't hear bubbles or fizzing near the battery, otherwise that means it's overcharged/charged too quickly and is causing electrolysis.

 

[CupCak3]

I'm back from business and was able to measured the current draw. .66 amps with nothing running. ~.15 amps with the radio fuse pulled. Would that extra 0.5 amps make the different?

 

[LTC8K6]

.66A is pretty high and is the problem, imo.

 

[brblx]

a standard small car battery in good condition will probably go dead in 2-3 days with that kind of draw. if it goes dead any quicker, the batt or charging system may be a little weak.

but the radio drawing half an amp is definately a problem.

 

[CupCak3]

Originally posted by: brblx
a standard small car battery in good condition will probably go dead in 2-3 days with that kind of draw. if it goes dead any quicker, the batt or charging system may be a little weak.

but the radio drawing half an amp is definately a problem.

My car only had problems when not driving it from Friday after work until Monday morning. Looks like I've got some work ahead of me over the weekend!

 

[bctbct]

Something similar happened to me on a vehicle.

First time an electrical shop figured out I had left the manual switch on for the under the hood trouble light.

Second time was about 10 years later and the same electrical shop figured out I had left the manual switch for the under the hood trouble light on.

I am such an idiot.