Battery suggestions for P7 light

[nwbrewer]

I'm currently running 4s2P Ni-mh AA's to run my D---I bin P7 dive light. The run time is rather pathetic, and the voltage sag on the AA's is so bad that I get a max, hot off the charger of 2.2amps. I'm using 2 linear 1.4amp drivers in parallel.

Battery suggestions to get me to 3-4 hours of burn on at full brightness? I have plenty of room in the can, I was thinking either 3 Ni-mh D's in series, or maybe 6c's in 3s2P configuration. Or 4 18650's, all in parallel. Thoughts for the group? Suggestions on best places to get batteries/chargers?

Thanks!

 

[DM51]

This is primarily a question about batteries. The fact that they are for a dive light is incidental.

The question therefore belongs in the Batteries sub-forum, where there are members with the expertise to answer it, so I'm moving it there.

 

[Packhorse]

Are you using AMC7135 based drivers? This will limit your options some what to keep the voltage close to the Vf of the LED.
In the end any of the options you listed should work OK. For me it would come down to cost and what charger you have/want. Also consider the buoyancy of the light. Your choice of cells will influence this greatly.

 

[nwbrewer]

Yeah, I'm using the AMC7135 drivers. I think I'd prefer to go with the Li-ions. I dive in the Puget Sound with drysuit and thick undies. Weight of the canister is fairly irrelevant, as long as I don't go SLA. I can just drop some lead to account for it. Any brand recommendation for Li-ions that would work well to get me that 3-4 hours? I'm guessing I'll wind up as 4P. Should I try and have a pack built, or just get individually protected cells and put them in a pack for discharging, charge them seperately?