I need a diffuse light source to light up pitch dark spaces. So i'm thinking about making a battery powered 12V LED car light. Since motorcycle batteries are too heavy and expensive I want to try it with a battery pack of rechargeable AA Ni-MH or Li-ion cells. My concern is that the battery won't last very long. What would be the best power source for this LED light? Can I calculate the estimated life of the battery? Would I need other parts to make this combination work?
is not clear.. you need to light a place in your car? why don't just make
aparallel connection from car's battery? Taking it from a light or the lighter is very easy
MOD...
Sry reading again I think that you don't need it in your car xD
well to calculate the autonomy you must take in consideration the power of the light(taking the DX light 1.2Watt) and the energy of the battery that is measured by the mid voltage(nimh have 1,2volt litio 3,7 volt) X the electric charge(an AA nimh have ~2300mAh and a litio 18650 have ~2500)
so a nimh AA can give 1,2x2300= 2,7watt for 1hour
and a litio 3.7x2500=9250mWh that are 9,25 watt for 1h
than with a 18650 litio u can light that DX's light for ~7,7 hours(ofc u need a mod coz is droved for a 12v or use a pack of 3X18650 in serie with an autonomy of 23h)
...You should clear where and how you want use that light if you want help, for example if are for external you can consider solar panel etc... or just buy a flashlight with a diffuser on top :P
Thanks for the fast answer. I do a lot of photography in underground places (bunkers etc) therefore I need a light with enough autonomy but bright enough to light up a room.
So with 3 x 18650 batteries I get 10.8V and would not need a mod. Would the light be bright enough, since it's not running at 12V?
That's a great idea, thanks! The bulb doesn't need to give much light. I just need some warm light to create an atmosphere. I work with long exposures anyway, so on a 30sec exposure any light will look bright.
