Badboy, MM, NG, & Li-Ion

[darkzero]

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?

 

[Greg G]

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.

 

[jch79]

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

 

[Greg G]

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.