New driver with odd behavior

Flashlight Modding and DIY Parts
1

I recently decided to upgrade an older Fenix L2P (2 AA / Luxeon emitter) and purchased this three mode driver -

http://intl-outdoor.com/eoslamp-aa-circuit-board-100ma-mid-p-385.html.

I paired it with an XP-G R5 4C emitter from the same supplier. Once installed (which was fun, since the driver was 17 mm and the pill had a 15 mm aperture.) I simply dropped in a pair of fresh alkalines that happened to be laying on the bench. While the light functioned, the spacings seemed off. With further investigation, here’s what I discovered about tailcap draws. All batteries were fresh.

Alkalines : 0.06 / 0.18 / 0.82

Energizer L91 : 0.40 / 0.28 / 0.21 / 0.30 ad nauseum. No discernable modes at all.

NiMH (Powerex Imedion, in this case) : 0.01 / 0.20 / 1.10. Perfection at last.

I repeated this set of tests three times - in each case, the NiMH ran the light perfectly and with very pleasing mode splits. I have no problem running this light with NiMH; I have plenty of them, and the modes are perfect for my tastes. But I am puzzled as to what exactly is going on, especially in the case of the L91s?

Oh, and as an edit, I have not come across a strobe in any of these combinations, which certainly doesn’t break my heart.

2

Just a guess, but the L91 seems to be over-volting the driver (outside of spec).

Maybe try using one that has been run down to below an alkaline?

3

The over-volt seems to be the case. It runs perfectly in a 1xAA configuration (I also have L1P tubes), so that’s how it will be used.

4

The higher voltage of the L91 (2 of them) probably put the driver out of spec. Even if the Alkalines have 1.5-1.6V fresh they will sag instantly (drop the voltage) even when you measure the current draw by putting your multimeter in series with the circuit you add further resistance to the poor alkalines, (that depends on the leads + multimeter shunt).