Can I use 8.4V with this Lambda driver?? <----YES I CAN!!!!

wight · November 11, 2014, 2:46am

vestureofblood:

vestureofblood wrote:
Well this does work.

I started by removing the XML which is direct bonded to the heat sink. The PCB is only for the = and – wire contacts.

After I machined off the nub for the XML an MT-G2 on a copper star was reflowed into place.

Once the driver was back in place I powered it up, and off we went.

Here is a picture of what the whole light looks like. The head is a 2 part beast. The silver is the factory mag head with some work done to it. The bigger part is the 109 LED harbor freight. An Oring covers the place where the parts were mated.

The driver is direct drive. I tested the current and its pushing about 8.3A off 2 li-ion. I think some resistance may need to be added. I was thinking the point of “no return“ on these was about 6 amp ish right?? So even if the emitter can handle it its a bit of a waste.

All in all I would say that its a shame Lambda is not still in the game. This is a well designed light IMO especially the driver. I could use a few of the boards. Not only this one but just before he left Lambda had a boost driver that could power an emitter to 3 amp off only 2.4V. I could really use a pile of those……

Thanks for the pics! I think you are confused about the MT-G2. When attached to a big heatsink the point where you lose output should be 11-12 amps. See post #16 here: crash-testing a MT-G2 on a copper Noctigon, graph done, mod done and repaired :-)

If there’s actually actually a need for that varapower style driver we could make some. I guess LVP and stuff could also be added without a lot of trouble. In fact, come to think of it… existing designs can probably work for it with only firmware changes.

If you need to limit current you should be able to put a resistor on the hot side of the potentiometer in order to reduce the duty cycle. Or if it’s wired the other way you might need to put the resistor on the GND side. It won’t hurt anything if you get it backwards the first time - you’ll just limit minimum the duty cycle, oops.

The 3A boost driver which operates on 2.4v sounds pretty crazy to me; that’s pretty high current on the pinput side (like 5A or so). I’d love to see some pics of one, hint hint.