How long can I keep my car on before the battery dies?

I want to hang out in my car for a while and use the battery to charge my laptop. A few years ago I did this for too long (maybe a few hours) and my car battery died. How long can you keep a car on before having to either turn it off or start the engine and alternator to recharge the battery?





Thanks!|||i use to do this all the time... just start it every hour and let it run a bit to recharge the battery... as long as you have gas in your car you have a laptop to play on :)|||Buy a solar powered charging unit, for car battery .You can probably go for hours with charger hooked up.Cheaper then running gas,and easier on the engine.|||It's up to the quality of the battery,I think at least one hour you can keep.|||Well start it at least one a hour or maybe a little longer to recharge the battery.|||Exactly 59 days 24 minutes and 7 seconds from when you posted the question.