NiZn Voltages and LED Direct Drive?

[BigusLightus]

I'm wondering if these new 1.6V batteries would be good for direct driving LED's?

2 cells = 3.2 Volts nominal or 3.6 Volts charged up and rested.

Isn't that the Vf range for several emitters?

 

[VidPro]

make a good "handy" light, just like 2x lithium does.
2X lithium and a 5mm led (preferably socketed) and it makes a quick easy mod, and simple long running low light. a few of them same thing, a high powered led run low, same idea.
if you want major juice though, like these 100+ lumen things then you need something more.

 

[McAllan]

Seems like NiZN are either a little low or a little high. You will get light with 2 NiZn but output will not be very exciting.

But 3 NiMH makes a great direct drive for a power emitter 1w or greater. Also when it seems to dim cells are practically empty and they won't discharge so far that there's a risk of cell reversal and thereby damage to the weakest cell.

But you can make a great light with 3 NiZn cells and a couple of AMC7135. They're small constant current linear regulators. Perfect for when the voltage drop is very small and therefore a buck regulator will be less effective. And in contrast to a simple resistor they keep the current constant as long as supply voltage is higher than LED voltage.
If you want them easily just buy some boards from DX with them already mounted. They have boards with 1, 2, 3 or 4 such chips. Each chip deliver 350 mA. So choose 1 is yo uwant to drive LED with approx 1 watt 3 if you want full power and 4 if you're using more powerful emitters or just want to overdrive it at expense of lifetime :devil:

Can't believe they aren't more used instead of those resistors people put in their Mag-mod etc. They're dead simple to use, unlimited numbers can be paralleled for wanted current and keep output constant as long as voltage is higher than the LED's at given current. When they can't keep up the light will fade slowly out as a direct drive - which with rechargeables will be quite fast but some light is there for some time.

 

[Kestrel]

2x NiZn might be a relatively better match for the lower Vf (~3.4) Cree XP-G rather than the ~3.7Vf of the earlier Cree's.

Check out threads from PaulInMaryland, he's done a lot with 2x NiZn configurations. He's a good source for info - he may see your thread & post here.