Battery drained overnight!!!!

chris308 · 04-16-2007, 04:25 PM

HELP!!

Just went to go unlock my door and the fob didnt work, so i though great my fob battery is dead. I get in the car and i get no electonics on i.e security light. Go to crank and nothing!!! Its a new battery, i just got it 2 weeks ago maybe if that.

"Backyard Mechanic" · 04-16-2007, 04:45 PM

I know you probably say that you did'nt leave any thing on,but I once left the mirror light on and did'nt know until the battery died.Also did you check your battery cables?Could you jump it?If so test your alternator,It maybe going out.Just trying to suggest idea's.Check for any losse wires from maybe cleaning your engine compartment,you may have hit a wire losse?Is your new battery maintence free,if not check the water level and give it a good overnight charge after filling it.Hope this helped.Test your battery for volts and then started it and test it again,you should have a higher volt reading,if not it's probably your alternator.Good luck.Rob

chris308 · 04-16-2007, 05:43 PM

yea, I'm pretty sure nothing was left on.

Gonna try to jump it now and check the alternator then.

navy2kcoupe · 04-16-2007, 06:16 PM

I've heard that you need to park the standard transmission cars in reverse to completely eliminate electrical drain. Did you park it in other than reverse? Maybe someone else will jump in here with additional info.
Andy

chris308 · 04-16-2007, 06:16 PM

Ok here is what i found...

Used my multi-meter to check batteries voltage while dead, it reads 5v.

I used a hand help batt-charger (kind you can keep in your trunk) and it wouldn't jump it.

I used jumper cables attached to another car and presto it cranks over and idles!!

Ok, while idling, i check the batteries voltage again. DIC says 14.2-14.4v my voltmeter confirms.

I remove + terminal to check the alternator and yep, it stays running. So i can assume the Alt is good?

I kill the engine and recrank to see if it comes on and it does. So I let it idle a bit and turn off. Recheck battery voltage and it reads 12.5v.

Suggestions...thoughts??

chris308 · 04-16-2007, 06:18 PM

Quote:

Originally Posted by navy2kcoupe

I've heard that you need to park the standard transmission cars in reverse to completely eliminate electrical drain. Did you park it in other than reverse? Maybe someone else will jump in here with additional info.
Andy

I have parked it in 1st since i bought it as i have all my previous cars. I guess vettes just want to be even more special!!

I'll park it in reverse tonight to see if it helps. Thanks for the suggestion.

**Rich Z** · 04-16-2007, 06:38 PM

Quote:

Originally Posted by navy2kcoupe

I've heard that you need to park the standard transmission cars in reverse to completely eliminate electrical drain. Did you park it in other than reverse? Maybe someone else will jump in here with additional info.
Andy

I think that only applies to the C6 model (standard transmission) and maybe only the earlier ones. I have NEVER parked my C5Z in reverse.

"Backyard Mechanic" · 04-16-2007, 07:01 PM

Running the engine for brief period Will Not charge the battery,It needs to have a load on it,Drive it around the block a few times and keep a eye on your gauges.The battery charger you are talking about does not always work if the battery is too low.You need to give it long charge on a slow charger.I have one of them and it does not work when a battery is completely dead.Your reading of low 12's is normal because the battery isn't fully charged.About you taken the positive off and the engine still running,That does not always means that the alternator is still good.From what you have described,I would say you alternator is probably good.But take it for a spin and then test the battery with the car Not Running and see what your volts are.If they are higher then you are good, if it stays low then you need to check{test} your alternator or some type of votage regulators.good luck.Rob.

chris308 · 04-16-2007, 08:09 PM

Thanks for the replies all

Ok, just got back from driving it for about 10 minutes, went to get some dinner. Pulled in the driveway, threw my VM on it and it reads 12.7v a little more than before.

I'm done messing with it tonite, gonna see if its dead in the morning or not.

chris

chris308 · 04-17-2007, 10:23 AM

Update:

Ok, this morning i go outside and i still have juice or enough to use the fob to unlock my doors. I get in and i have dash lights woo-hoo. I start it up, it kinda had a hard time but alas it started. I let it idle a bit and then I noticed that my radio presets were back to default. I set them right before leaving the car for the night. So appearantly I have a parasitic drain greater than the normal allowance of 20mA. I have read the diode in the alternator can drain the battery and still be Ok if bench tested out of the car.

Looks like im going to have to do a drain test and start pulling fuses!!