how long would it take 4 LEDs to run a battery dead?

 

How large of a battery?

Assuming a normal 5mm LED... a LONG time... hell, it takes forever for my LED pen light to discharge 3 AAAA batteries...

I could get into the math, but I really don't feel like it.. I spent most of the day figuring out thermal de-rating curves for the LEDs and IR Emitters I'm working with at work...

 

a reg camaro battery, just wanted to make sure there not goin to run my battery down

 

Only if you leave them on for an excessive amount of time...