dead battery... again

[radgto]

I didn't have any problems at all with it last year, then I shattered my heel at work and the car sat for 5 months w/o being driven.
after sitting for 5 months, battery is dead. no surprise since it's 5 years old.
I get a Optima red top and everything seems fine for a couple weeks, then after sitting for the weekend, I go to start it and it's dead.
I take the alternator off and have a local store test it. No problems, Test the battery... again, no problems.
I figured I left something on like my lights or fans. Oh well.

Ran fine for a couple weeks, then it sits all weekend again because Michigan had a winter relapse and when I tried to start it again... DEAD!

What can it be?

Alt and battery checked good.
nothing was left running.
I do not have any aftermarket alarm/starter etc.
It hasn't thrown any codes

EDIT: forgot to mention that the cables look good too.

Thanks for any help.

Duane

[erimar77]

so after you get a jump, everything works fine?

[radgto]

Yeah, I start it with a battery charger and everything is normal until it sits for a couple days.

Duane

[erimar77]

how long have you had the battery? just because it's an optima doesn't mean it's perfect. i'd either contact the place you bought it from, or optima themselves and say you got a hold of a bad battery.

[Moofert]

Double check your connections to the battery, could be that there is acid buildup limiting the amount of amps getting to the starter. It wont turn over without a high amperage.

[radgto]

I've checked all the connections, they all look new (car only has 31,000 on it and is detailed to the max)

When it dies, there is NO juice left, no remote locks, no dome light, no stereo, etc.

As soon as I hook it up to the charger, there's lights and such, and after about 5 minutes it'll start.

The battery is about a month old.


Thanks

Duane

[sunrunner_pei]

Have you tried giving the battery complete charge with your charger, rather than the alt? If the battery has been killed, the alt has to work overtime to actually charge it fully. Even when not running, the car draws a fair amount ov power. Enough to kill a good battery in a couple weeks if left to sit. My advice: Take the battery out and give it a nice slow charge, then re-install. While it's out, take the time to inspect the battery cables and the battery terminals fully. Look under the rubber boots of the cables. If tere is any corrosion, clean it away before reinstalling the battery.

[tenspeed]

I would suspect a low amp draw on the battery. Write down all your radio station presets, disconnect the positive side of the battery and put a amp meter inline. Voltmeters usually have up to a 10 amp function.

There should be just enought amps to keep the radio clock on time and the presets. That should only take a couple hundred milliamps.

If you are seeing a higher load, start pulling fuses one by one and see if the amps drop. If you see a large drop, you have a problem with whatever is being fed from that fuse. Leave that fuse out, reconnect the battery and start the car to see what is not working if you can't tell from the label.

You can also leave the fuse out when you park for more than a day.