Could my cigarette lighter cell phone charger really have ruined my alternator?

Factual Questions
1

Last Tuesday I bought a cell phone charger for the car, which you plug into the lighter socket. I used it off and on all that afternoon, and didn’t notice any issues.

Not long after, some time on Wednesday, I noticed that the alternator light was lit, and stayed that way, but everything in the car continued to work fine, with no noticeable dimming of bulbs, or difficulty in turning over the engine. Nor had their been anything in the recent past, or ever, to suggest that I was having alternator problems. I tended to dismiss the idiot light, because, hey, another light is always telling me my seat belt is unfastened when it isn’t.

Early Thursday evening I was returning home. The alternator light was still on, but everything was working. Then the air bag warning light began to flash–and after a couple more minutes the entire car stopped working, except for the lights. I was halfway through a left turn and barely managed to pull over by a fire hydrant which was much too close to the corner.

I’d been wanting this charger for a long time; until I got it, I could only charge my mobile at home, or from my PC. Now that I have it, I’m afraid to use it. Can it really have been the culprit?

FTR the car is a '00 Nissan Altima.

2

I highly doubt it. Even the wimpiest automotive alternators are capable of sourcing several tens of watts. A charging cell phone isn’t going to draw more than a watt (and more likely a good deal less.) What did happen, I can’t guess, but I’m positive it wasn’t the charger.

3

Sounds like your “black box” crapped out on you.

4

Almost no chance of it killing your alternator, and if it did, your alternator would have given up the ghost soon anyway. Given the age of your car, its not unusual (assuming you hadn’t replaced your alternator recently) for it to go out.

5

It’s only a coincidence. You would have had to draw ridiculous amounts of current trough the charger, and that what fuses are there to prevent.