Ok Im planning to start a project where I build a light that runs on battery power this is what I had in mind .. I want to purchase a cree XML-t6 light and power it with a battery ... My first attempt turned out bad I used a c4 streamline led and a RC baterry ... I need help figuring this out I want to run the cree XML-t6 with batteries but I want to last a long time so I'm looking for a big long lasting battery that is portable if u all have any ideas on how Incan accomplish this let me know I need a run time of about 6 hours

 

The specs for a Cree XMLT6 says 3.7-4.5V @ 2.7A.
If you want this to run for 6 hours you will need at least a 18Ah battery.

 

The most efficient way to maximize battery life is to use a constant-current switching regulator to power the LEDs. You would then need a battery with about 100 watt-hours of energy (Ah times battery voltage).