Tech question about lights

FSR_XC

Trying to find out how long batteries will last on a light.

5w Cree
x3 1.5v AAA batteries
or
x3 1.2v AAA 1000mAh

Anyone help?

supersonic

WIthout knowing the exact details of the torch ie the driver for the LED, and battery layout, and the capacity of the other batteries, it cannot be calculated.

FSR_XC

Don't know if this helps, but looking at this:
http://bit.ly/cRENxp

supersonic

If the light is drawing 5watts then:

P = VI
I =P/V
I = 5/3.6

So the light will be drawing around 1.4 amps or 1400ma.

1000mah batteries will last 1000/1400 = 0.71 hours = 43 minutes.

FSR_XC

Not that long then

Thanks for the info.

supersonic

Look for the highest mah you can. I use Energizer rechargables and seem to last ages. 1.2v will not actually pull that much current or power if no driver, so you will be slightly less bright, but longer runtime.

diy

Should be able to replace the aaa holder with an 18650 Li ion cell will last 6 to 10 times longer assuming a 2.5amp cell

konadawg

Probably, (certainly?) your 5W Cree is anything but.

http://www.candlepowerforums.com/vb/sho ... p?t=244298

If it were (irrespective) it would not be powered by AAA, or even AA, but 18650.