my car wont start
 

So my car has sat for a week in minus 30 weather for a couple days and when I went to start it, it wouldn't. So I know the battery is dead but. I hooked up a charger and I had the car running for a good half hour. And when I took the charger off the car stopped running. So I figure that it may be my alternator. So just wondering if anyone can confirm or deny my guess.

You kept the charger on while the car was running? I would not do that!!!

When you had the car running for that 1/2 hour, were you driving it? Did you have a voltmeter connected to it?

Indeed-some more details about when it was running would be appreciated. Is the battery holding a charge? Need to see how it does without the charger but I would guess your battery is either totally dead or you alternator is not functioning.

But if you get it running, drive it, and if it and everything electrical just dies-alternator for sure. Any codes? My wife's car would crank but not turn over because of a crank sensor, but since you have managed to fire yours up I would not suspect such.

I'm actually thinking both the alternator and the battery are bad, one going bad probably fried the other. The alternator obviously should maintain a charge once started, and it isn't. If the charger was hooked up to the battery and the battery died instantly when you disconnected the charger, then you have a couple bad cells. I would think it would run for at least a minute or two having the charger hooked up that long.

A charger is for charing the battery not jumpstaring it, and if you are going the ley your car sit for periods of time you should get a trickle charger to maintain the batterys charge

Yeah my car only sat for 3 days before I tried to start it again. But the reason I left the charger on is because when the car ran for 1 minute I was gonna take the charger off and take it for a drive. So I put the charger back on and let it run for half an hour. And again when I took the charger off it died again. And my battery is only 4 months old. So I know its dead but I don't think it conked out.

If you have the time disconnect one lead in the battery and charge it up realy good with the charger. Also, the battery should have a warranty so I assume you saved the reciept. 3 days should be no problem to let it sit if the alternator is OK. I let mine sit mostly all winter and don't use it for weeks (sometimes > 1 month even) at a time (I don't drive it in salted roads) and my car starts just fine. I have a winter beater I drive for that.