Need some help with 12v regulation (hid mag build)

Hey guys,

I'm planning on a build that consists of a 2d maglite and the WA 14w ballast. This ballast runs at around 12v (9v-16v to be exact). I would like to run it off 8aa nimh cells but the voltage is a little low to run the ballast near spec. Also would like to run it off 2x imr 26650 cells but same thing- voltage too low.

Is there a driver that I could use to bump the voltage up? When running I believe the ballast uses less than 2 amps. But startup may use 5 amps for less than a second though..

Maybe it would be ok to run 6x aa sized li-ions in a 2x3 parallel configuration giving about 12.6v?

Any ideas appreciated.
Thanks

spc said:

Is there a driver that I could use to bump the voltage up? When running I believe the ballast uses less than 2 amps. But startup may use 5 amps for less than a second though..

Click to expand...

Don't know if there is one ready available, but one could certainly be constructed (though maybe not economically). But from only a technical perspective, you're likely to suffer 15% or more efficiency penalty -- not good.

Maybe it would be ok to run 6x aa sized li-ions in a 2x3 parallel configuration giving about 12.6v?

Click to expand...

Should be ok, but kinda low capacity.

If you like the 8xAA option, you could try the NiZn AAs (brand is powergenix, IIRC); basically same energy as Eneloops, but more V, less Ah. These want CC/CV charging like Li-ion, though, so either balance taps or disassembling to charge would be best. (You can get 4 cells with a 4-slot charger, so 2 of those would work.)

Or on the Li-ion side, how about 3xC-sized Li-ion? Either AW's IMR26500 (only 2.3Ah) or DX's no-name LiCo 25500s (about 3Ah, but unbranded, unprotected cells with the potential to go boom make lots of folks understandably nervous) would handily beat the other options in capacity. I don't know the behavior of the 14W ballast, but if it cuts out at 9V or a hair below, it would be quite nicely suited to a 3s Li-ion battery, as it would automatically prevent overdischarge.

Thanks Benson, I forgot that 3 "c" cells would fit (with some spring/tailcap modding). I wanted to keep it 2d size - to look oem.

I guess this thread can turn into a build thread with beamshots and so-forth, as thats the combo I will use. :thumbsup: