Flat battery, wouldn't idle?

[-Leigh-]

As I'm used to the auto lights, when it was foggy earlier, I switched them on, but somehow managed to leave them on when parking up, even though there's a warning tone lol.

Car wouldn't start, but luckily had a booster pack, but the car wouldn't idle, just kept dying. This continued for 20 mins or so (in traffic, a nightmare trying to keep revs up in traffic) until finally it's sorted itself out.

Was it to do with low voltage? I thought once an engine was running, it didn't rely on a battery??

 

[DannoTheGreat]

if the lights were on it wouldn't charge the battery very much.

 

[-Leigh-]

if the lights were on it wouldn't charge the battery very much.

Sorry, I flattened the battery buy leaving the lights on for an hour whilst parked up. Jumped it, and then drove with nothing on at all. But it still wouldn't idle.

 

[DannoTheGreat]

ah sorry buddy, misread

 

[Jay Payne]

Sounds like the ecu had to relearn the settings or something

if the lights were on it wouldn't charge the battery very much.

makes little to no difference to the output of the alternator on a modern car.