Battery drain in the cold
 

Anybody else have nasty battery drain in the cold?

Went out to do some cruise tuning and had no trouble starting the car. Everything seemed fine, until I was idling in a parking lot, looking over my log, and the laptop started flickering on and off battery. Checked the voltage in megatune, and I was bopping around 11.5-12. Drove around the block and checked V at idle...12.5. Started looking through the log again, and same thing. Volts ~12. Tried again, then sat at idle watching the V-meter. I could practically watch it dropping from 12.5 down to 11.8ish.

I imagine the battery just drained quite a bit in the recent cold (haven't driven it in about 2 weeks) but damn. Maybe I have a drain somewhere, who knows. I know the alternator is good...rev the engine and V shoots to 13.5-14. It's now on a trickle charger for the night, we'll see how she does tomorrow.

I haven't had any issues and i'm just north of you, we've had mean temps around 55 here with lows of 29-30. I haven't had any battery drain issues though I am familiar with them. You have to charge your battery 100% and you should be fine. A partially charged battery will be fine in warm weather but soon as it gets cold you're screwed.
Considering the car started no problem initially though makes me wonder if you don't have a different issue. Like maybe your battery is dying and isn't taking a charge or maybe you have some dirty battery grounds. The PPF, or battery posts themselves.

I just bought the battery a month ago, so it hasn't proven itself yet ;) I wouldn't rule it out. I did clean up the cable ends when I threw the battery in, and cleaned up the ppf ground a couple weeks ago. I added an extra MS ground not too long ago too, and cleaned up the grounding spots in the engine bay at that time.

Maybe the battery has never been fully charged since I bought it...it has quite a layer of dust on it at OReilly's!

We fixed up his ppf grounding when we did the diff swap. It's good, I did it myself. :)

Ben, maybe you need an alternator? I've never known one to be bad, but assuredly they must fail from time to time. My dad's got a load tester.

Yeah, alternator may have taken a shit, but I highly doubt it. If it had, I doubt I would see the volts increase so much with revs.

At idle you should still see 13volts at the battery terminals while it's running. On other cars that i've been around anything less than that means dying alternator.

Ben it could have dirty or damaged brushes, which would do exactly what you're describing.

it could just be a shitty battery, not taking a charge properly
it could be the alternator, i had a similar problem when mine was dying, the V would jump up with revs...
my $$ is on the alternator though

Ive had an alternator fail.

Hook up a resistance heater that warms up the battery when your turn on the ignition.

Alright, well, went and checked the alternator belt. It had stretched out, and I didn't have any more adjustment. I scrounged around and found my old belt, which indeed was a bit shorter. Threw it on, tightened it up, and checked voltages. 11.8V with the car on, but not started. Started the car, and 14V at idle. Seems as if this is fixed. Thanks guys.

damn belts...

Seems the alternator belt has the opposite problem of my waist belt...the alt. belt keeps needing tightening ;)

Try breaking your leg and arm to see how that works out for your waist line. I have all sorts of nice 32W slacks and jeans that I have NO HOPE of ever wearing again. 38 FTMFW