Just replaced alternator (1 week ago) because I put in an oversized subwoofer (made truck go boom) which killed it. Took out subwoofer for now untill I go on the high output alt. next time or install a cap? for deep cycling for the sub. For now, got rebuilt stock alt. in.

Anyway, as I was waiting on a gas station driveway to pull into traffic, engine died without warning - no restart, no noise whatsoever, clock out, everything blacked out. My lights were on at the time, radio was on, vent fan was on, and I was rolling the back window up, and everything died. Stepped outside vehicle to look under hood, then noticed the lights on. So I turned it off. But then it started right up. WTF is going on? I'm baffled. We did have heavy rains here right before it happened, and I have one hell of a leak in the passanger side (don't know where it's coming from, but floor is soaked). Could that have caused a short or drain?

Haven't happened again since (3 days ago and counting). Thought about bad battery, but it sounds strong now (it's a red top) and battery charge gage is high. Should I check battery see if it's bad? I'm scratchin nogin. Any ideas appreciated if this has happened to you. Thanks.

How big a sub did u have? I had over 1000w rms running off a stock alternator for over a year before i upgraded (and i still have it as a spare)

Not sure, but it was about 14" diameter - was huge. Also had it cranked to "11" most of time (old fart metalhead). I got it from stepson, just layin' around his room and thought I'd use it. I already have middle-of-the-road amp installed before.

It's doing fine so far with the sub pulled out, but I suspect it's a bad battery (pretty old) & will have the battery checked soon or if it dies again - will just keep fingers crossed for now.

How high is the gauge? It would be best to measure your battery voltage with a digital meter(engine idling). Anything over about 14.6 is too high.....if your battery wasn't bad, it will be from being fried.

Yeah it's definately not the Sub doing it as long as the electrical system is in good working order. It's when youre charging system is dieing, that the sub will make it die much faster! Once you get it fixed, you'll be fine with the sub, you are probably only runing 2-300 watts, so you should be more than fine. To take into account, i run a 0 Gauges wire from my battery to amps, and it does not kill the amplifier (think how many amps that draws).

Also, when you hook up a new alternator, run a 4 gauge wire with a built in fuse straight to the battery, and upgrade the ground wires between the frame, body, engine block and battery, you will get some extra amps from your battery and it wont work your alternator as hard.

I'm having the battery checked today and will try the wire gauge upgrades. Still hasn't happened again, but don't want to take chances. Thanks for the heads-up!