Badboy, MM, NG, & Li-Ion

I have two sandwiches that are both using USXOH. One is a NG750, the other is an old MM adjustable. If I run a li-ion in either one I get the angry blue after 30 seconds or so. I know it's not because of heat cause it doesn't even get hot when it turns angry blue & I can run them in NiMhs constantly without turning angry blue even after they get very hot.

However, I have a McLux with a BB667 Rev.1 with a USXOH & if I run a li-ion it it doesn't get angry blue. Also have an Arc LS that is running a USXOH at 611ma & if I run a li-ion in that it doesn't get the angry blue either.

I know li-ions are not recommended to use with Badboys, MM, & NG. I know they're turning angry blue probably because of over voltage but why do the BBs in my McLux & Arc do not do this?

The blue has to be from the LED running hot, right? That's the only time I've ever seen that happen in my limited time in flashlights.

I built a NG 750 Seoul LE that turned blue within 10 seconds or so on Li-Ions, but it'd run fine with a primary.

It was explained to me that the Vf of a Seoul LED is lower than that of the Li-Ion, and since the NG is a boost converter, it doesn't/can't down-regulate the voltage, you get y'rself a bluey!

I think you could theoretically get an abnormal Seoul LED that has a high Vf (>4.2v), which might play friendly with a NG and Li-Ion, but why not just get a GD?

Good luck and have fun! :wave:
john

From the specs of the NG driver:

"Vin overdrive voltage: Vout+0.7V "

So, 4.2 volts in *ought* to be ok with a 3.5 or higher Vf emitter.

Maybe you have yourself some really low Vf Seouls, or those particular boards are different than the others?

I guess you could change the sense resistors and bump those drivers to 1 amp and see if it still does it. That would raise the Vf of the emitters slightly.