Wich converter to run on 1xCR123 or 1xRCR123

Hi everyone,

I would like to build a luxIII LE for a 1x123 light. I would like it to be able to run on one primary 123 as well as one protected rechargeable li-on 123 (3.7V).

I understand a nexgen cannot run on li-on to power a luxIII (please correct me if I'm wrong), because the input voltage cannot be hight than the output voltage.

So which converter would do for me? Wiz2?

Oh, and BTW I would like a regulated current of 750 or maybe 1000mA.

Thanks a lot for your help :candle:

A Nexgen 750 or 1000 will be fine with a Li-ion cell. The 750 will initially run out of regulation and in direct drive, sending somewhat more than 750 mA to a J bin Luxeon, but as the cell voltage drops it will continue to deliver 750 mA to the LED. I think the Nexgen is a better choice for single cell CR123/RCR123 lights driven at these levels than a Wiz2. If output with a CR123 is not critical, and you will use Li-ion primarily, the Wiz2 ifs fine.

Thanks wasBlinded for your help,

Still I'm not sure I understand the out-of-regulation thing with NG 750.

- Is the NG converted a boost only converter, so when the input is higher than the Vf of the led, it goes into direct driving? (I guess that would explain this behaviour with li-ion rechargeable)
- What will happen with a NG1000 running on a li-ion : will the output current go higher than 1Amp?
- is there anything wrong with the wiz2 that makes the NG better for 1 cell application?

By the way, I would like to drive TX0H leds. In the future, I may consider driving Cree leds also...

Thanks again!

By the way, CR123 running at 1A is near impossible. At 1A, the voltage will sag to 2.4V and almost no converter will hold regulation.

tino_ale said:

Thanks wasBlinded for your help,

Still I'm not sure I understand the out-of-regulation thing with NG 750.

- Is the NG converted a boost only converter, so when the input is higher than the Vf of the led, it goes into direct driving?

Click to expand...

Yes, minus the slight resistance of the convertor circuit

- What will happen with a NG1000 running on a li-ion : will the output current go higher than 1Amp?

Click to expand...

It might with a low Vf lux, like a TXOH

- is there anything wrong with the wiz2 that makes the NG better for 1 cell application?

Click to expand...

The Wiz2 will shut down at 2.5 volts, well before a CR123 is fully discharged. This is to protect Li-ion cells.

Thanks a lot, I understand now :twothumbs

I guess I will have to choose between CR123 and RCR123 primarily use... until the GD converter become available.

I have a NG750 which I run on Li-ion all the time. It has a UWOJ Luxeon and does just fine in an Aleph2. Even your TXOH would probably be fine with a Li-ion cell, but prolonged runtimes might be stressing it because of the current it would draw. Still, a T bin Lux is pretty cheap these days. IF you want to be safe, you could do it fine with a J bin Luxeon, or even a K bin.