How to power an outdoor (streetlight-type) light with car/truck battery overnight?

There are really 3 parts to my question:
1) Is it even possible to power something like a high pressure sodium lamp of 100-400 W from a car battery for about 8 hours?
2) How would you set this up?
3) If the battery is getting drained to empty (or close to empty) every 2nd or 3rd night, what will be the approximate lifetime of the battery?

Thanks for your help!



400W,call it 500 for losses, 500W / 12V = 41 A ! 41A for 8 hours = 328 Ahr - thats a pretty big car battery or a truck battery.

Deep cycle like that ? Very poor. Maybe 80 charge cycles.

Steve