how to build the best spotlight for this battery pack???

[lateround]

I have a 21v battery pack i would like to come up with the best most efficent spotlight that would go with it that wont drain the battery right away currently has a halogen 50w bulb on it and would like to get something brighter for it... the tighter the spot the better and this is a handheld light so it cant be anything to big thanks for any help

[127.0.0.1]

must know the chemistry and type of battery

[lateround]

there is 15 batteries wired together each being 1.4v what i can read on the side say VH 4000 4/3A High Cap

[BVH]

Can you see any markings on the bulb? I've not seen any Halogen bulbs capable of running on 21 Volts, plus or minus, but then I'm used to working with typical 12 Volt automotive bulbs. If there are 18 Volt (nominal) Halogen bulbs available, then you could maybe find a 100 Watt version by Goggling?

[alpg88]

most likely overdriven 12v bulb, 15 nimh cells is 18v, you can see 21v after charging with no load, under load they sag. any long life bulb (2000-3000hours) will handle 18V.

there are relatively few manufacturers that make 4\3a cells (nimh 18650), but i doubt they can handle high discharge. never seen one higher than 1c.
i wouldn't use any bulb bigger than 35w.

[FRITZHID]

could also be an underdriven 24v from train, tractor-trailer, or aircraft. (just a thought)

[Illum]

yep... http://www.varta-microbattery.com/en...ts/DS55140.PDF
NIMH, 21V would mean either a 18-cell pack thats empty or 14-cell pack charged to full. 3600mah... total of only 75WH to work with, not really usable in a 12V halogen setting, unless your hoping to run it for a couple minutes

[lateround]

the 2 bulbs i currently use one is 12v 50w and the other is 13v 100w aircraft bulb the 100w bulb is a little brighter then the other bulb, Also is there some type of led bulbs that could work in the place of these bulbs? if so any way to off set the white a head piece i also use with this battery pack is plenty bright for what i use it instead of the spotlight but its too white and blends alot together where the dirty white color the spotlight puts off helps pick things apart better

Also i use the led head piece a most of the time, so i only shine the spot light at most 5minutes before i switch back to the led light

[alpg88]

yep... http://www.varta-microbattery.com/en...ts/DS55140.PDF
NIMH, 21V would mean either a 18-cell pack thats empty or 14-cell pack charged to full. 3600mah...

no it is not, it is 15 cells as op mentioned before