E1/KL1 "vampire" - Is the Madmax Lite right for me?

[Inliner]

Hi All,

I have a nearly unlimited suply of CR123 primary cells that were discarded when they dimmed on a P60 bulb. Sitting voltages range from 2.5V to 2.9V I also have an E1/KL1 HA-BK combo that I'd like to put a red led into. The idea is to get at least another 10+ minutes of usefull light out of these cells. I think a Red led behind an optic will be cool and pair nicely with my H501R for draining AA cells.

I chose a red Rebel because it seems to have a higher Vf those most other red leds 2.9 Vf typical. This should let me run a boost only driver and still be safe on a fresh cell should I need to use one.

Looking at Torchboy's great chart, I found the Madmax Lite. This seems to be a pretty oldschool sandwich driver for MiniMags and I'm hoping someone who reads this had some experience with one back in the Luxeon hayday. Will this do what I want it to? I'm not trying to suck out every drop of juics, but if the Madmax will keep the Rebel running until 0.8 Vin I'd be pretty happy. Any thoughts? I don't really want modes or need constant current, but preferrably just a diminishing output until dead.

Heck, how well does the stock driver drain cells?

Thanks:wave:

 

[nein166]

This should be in the Sandwich Shoppe Sub-forum maybe a MOD can move it for you

I know the Madmax will run down those CR123 cells because I used 1 AA to drive an XR-E P4 to a decent output. I think the MMlite ran for about 8 hours like that getting weaker and dimmer until the LED couldn't light at the supplied voltage. If I needed high power I'd stick in a 14500, but you shouldn't do that with a Red Rebel since it will go DD at 4.2v. If you use the MMplus you should be safe as well. You'll pull more power from the cell and run the Vf of the LED higher as it goes up to 700ma. I just hope you didn't go for a high output bin since they have a lower Vf than normal (2.20v typ.)

Do the CPF thing and buy one of each.
Mount the LED in the KL1 and give it long lead wires so you can test both boards, before its closed up.

I had not noticed the price was so low on the Madmax boards thanks for bringing them back to my attention.

 

[nein166]

Had a thought... if you get the lowest output bin(LXML-PD01-0030) and drive it with a MMplus (~700ma) the Vf typical is 3.6v safe for draining cells and fresh cells plus your still only going to get 65lm max on those fresh cells, probably close to 30lm on a used cell. Lowest bin might be cheaper too

 

[Inliner]

Thanks Nein. I took your advice I got both the lite and the plus. I'll let you know how it turns out.

FWIW, I ordered Rebel p/n LXML-PD01-0040 (but on a MCPCB) for higher flux bin, but it still has the higher Vf.