Just an idea, considering a cheap magicshine p7 lamp only and wondering if I could run it in AA rechargeables. I’ve loads of 2500 amphour ones, 6 gives 7.2 volts nominally. Would it run the light? The Li-ion batteries are quoted at 8.4v but that looks like the charging voltage, 2×18650 is 7.4v so only just above 7.2, but I’m not sure how the voltage drops as they run down or how sensitive the light is to voltage. If I could get 80 minutes of light I’d be happy. Anybody tried?

Can’t see why it wouldn’t work, depends if the driver board in the torch will take an input of 7.2v. I doubt it’d break it to try. It’d be heavy tho. If you’re really bored you could look through the driver boards on DX and try and spot the one in the light (compare visually, they’re not a consistant on from what I can make out), the page will then give you the board specs.

Note, i’m not an expert!

depends if the driver board in the torch will take an input of 7.2v

Of course it will. As always there’s confusion due to the different ways of quoting battery voltage when in reality batteries actually have a range of voltage from fully charged to empty. That 8.4V is the fully charged voltage – a LiIon cell is nominally 3.7V (used to be nominally 3.6V – not really sure why the change), but 4.2V when fully charged and generally cut-off is at 3V. Meanwhile a NiMH cell is nominally 1.2V, but ~1.4V when fully charged, and normal cut-off is 1V per cell. Therefore 3 NiMH cells are a pretty good substitution for 1 LiIon cell.

It should work just fine, though clearly those cells are lower capacity than the stock pack.

I built a quick adapter to run them off RC battery packs at 7.2V.

It works, though I’ve not done a real life test of them (just switched the light on and checked everything appeared to work okay).

Will 6v be below the cut off point of the LED driver though?

Probably not. The LED only needs 3.5v(ish) and generally drivers only need 10% over that.