Car stalled and restarted after some minutes

Question

I have a very old car which uses mechanical transmission (Maruti Zen)

Recently while driving on the road, I switched off the engine because of heavy still traffic. I forgot to turn off the head lights while doing that and this happened for around 1 min.

After that, when I tried to start the car again, it won't start at all. I waited for around 30 mins outside the car and when I again tried to start the car after 30 mins, it started to my surprise !!

My question is it seemed like a battery drain issue, but how did it start after 30 mins, if the battery got drained.

P.S: The car had stalled on an earlier ocassion, but that time, it started after someone pushed the car, while I put it in 2nd gear (and pressing/depressing the clutch pedal)

Answer 1

It has been my experience that a battery has what I call a "rebound". After a large draw is put on it, such as the lights for a period of time, it loses some of it's peak power. Then when the draw is taken off and left to sit, it rebounds and regains some of its energy. This may have given you enough juice to get your car started. I don't have a scientific reason for this, just anecdotal evidence that it happens.

All-in-all, I'd think your battery is almost done, though. A couple minutes of draw on the battery from the head lights should not cause this issue. I've accidentally left my lights on for a much longer period of time (30+ minutes), turned them off, then attempted to start the vehicle with success. The engine might lug over (not want to crank very well), but it eventually fires and regenerates the battery.