Battery Drain in a 2002 Camaro SS

[danachevroletfor1967]

I wanted to post this and get some feedback from you guys. Is there an easy way to check if a battery is being drained even with nothing in the car on? I bought a new battery (AC Delco) from my local dealership in June, 2020. Last Dec., 2020, I asked them to check the battery as my car wouldn't start right away and gave all indications of a weak battery. They said I didn't drive the car enough to keep the battery charged. I have previously let the car sit for up to 2 weeks between drives with no problems.
I checked the battery with a tester and it showed low, 5 volts, after sitting for a week. It finally started the car after 3 tries. The alternator checks out fine. After driving for 20-30 minutes and shutting the engine off the battery shows 12.5 volts. If I let the car sit for 2-3 days and try to start it I get the same slow response time.
I'm guessing either something is now draining the battery that didn't before while the car is sitting in the garage or this new (from June, 2020) battery is a dud and can't hold a charge. What do you guys think?

[ronzz572]

Maybe disconnect the battery while it sits a few days. I've had new batteries actually short out causing a drain. This would verify if the car is the problem or just a bad battery.

[Big Block Bill]

Originally Posted by danachevroletfor1967

I wanted to post this and get some feedback from you guys. Is there an easy way to check if a battery is being drained even with nothing in the car on? I bought a new battery (AC Delco) from my local dealership in June, 2020. Last Dec., 2020, I asked them to check the battery as my car wouldn't start right away and gave all indications of a weak battery. They said I didn't drive the car enough to keep the battery charged. I have previously let the car sit for up to 2 weeks between drives with no problems.
I checked the battery with a tester and it showed low, 5 volts, after sitting for a week. It finally started the car after 3 tries. The alternator checks out fine. After driving for 20-30 minutes and shutting the engine off the battery shows 12.5 volts. If I let the car sit for 2-3 days and try to start it I get the same slow response time.
I'm guessing either something is now draining the battery that didn't before while the car is sitting in the garage or this new (from June, 2020) battery is a dud and can't hold a charge. What do you guys think?

Here is the first place to start:

Disconnect the positive cable and connect a standard 12volt test light in between the cable
bolt / end and the battery lug. If it lights up with everything off, there is a draw in the system. the brighter the bulb on the test light the higher the amp draw is. If the test light does light up, pull fuses one at a time to find which circuit the draw is in. If the light still lights up with all fuse pulled, disconnect the wiring to the alternator and then the starter. See how that works before you blame the battery. What brand / manufacture battery is it? I have changed brands of batteries in my shop 3 times in the last 5 years. Currently I am selling Napa Batteries manufactured by East Penn Manufacturing little to no problems. I threw both AC Delco and Interstate out. Let us know how you make out, good luck.

Bill

[ronzz572]

Originally Posted by Big Block Bill

Here is the first place to start:

Disconnect the positive cable and connect a standard 12volt test light in between the cable
bolt / end and the battery lug. If it lights up with everything off, there is a draw in the system. the brighter the bulb on the test light the higher the amp draw is. If the test light does light up, pull fuses one at a time to find which circuit the draw is in. If the light still lights up with all fuse pulled, disconnect the wiring to the alternator and then the starter. See how that works before you blame the battery. What brand / manufacture battery is it? I have changed brands of batteries in my shop 3 times in the last 5 years. Currently I am selling Napa Batteries manufactured by East Penn Manufacturing little to no problems. I threw both AC Delco and Interstate out. Let us know how you make out, good luck.

Bill

This will work but you may have to connect a jumper wire across the test light connection for about 5 minutes first. Then disconnect it.. That will supply enough power to shut down any or all the electronics in the car.

[Big Block Bill]

I forgot to mention pulling any relays as well especially for time delay interior or head light circuits.

Bill

[danachevroletfor1967]

Thanks guys for your responses. The battery is an AC Delco brand. I drove the car today after having a hard time again starting it, then disconnected the battery and checked it with a battery tester, 12.0 volts. I'll let it sit with the battery disconnected and then use the tester again in a couple days. Sometimes I don't think of the simplest things first.

[Big Block Bill]

My bet the battery is junk.

[BB70]

The test light method is ok for non- computerized older vehicles, but late model stuff needs to be measured in milliamps using a digital meter capable of such measuring. I reccomend taking it to a shop that you trust to check the car.

[Big Block Bill]

Originally Posted by BB70

The test light method is ok for non- computerized older vehicles, but late model stuff needs to be measured in milliamps using a digital meter capable of such measuring. I reccomend taking it to a shop that you trust to check the car.

Disconnecting the power source, be it a fuse, a relay, or power source one at a time with the test light connected between the battery and negative cable will tell you which circuit is causing the drain when the light goes out, computerized vehicle or not.

Bill

[danachevroletfor1967]

Well I finally got around to connecting the circuit light and pulling fuses. Good news: I found the circuit with the power drain as the light only went out when this fuse was pulled. The fuse is identified as PWR ACCY which I am assuming means power accessories. Bad news: under the usage section it lists this fuse as controlling parking lamp relay, hatch release relay, power mirror switch, radio, shock sensor (don't know what that means), and instrument cluster. I will be taking the car into a shop I trust to have the correct circuit narrowed down to be the problem causer.
Any of you guys have any ideas as to which circuit that utilizes this fuse might be the problem?