Hello all.
Many Novatac emitter swaps happen around here.
However, I don't see drive current data anywhere. (might have missed it?)
So, I thought that I would share some info from my latest 120P mods.
Stock Seoul P4 = 650mA
K2 TFFC = 1000 mA
Cree XPG R4 neutral = 1500mA
It seems that these drivers respond to lower Vf with more current.
The #s hunt around a little bit, with the emitter heating up, but not much.
I gotta say, I'm keeping this new neutral XPG R4 setup.
Something like a 400P now.
:twothumbs
Interesting. These numbers don't quite make sense to me. It seems that the Novatac doesn't have a current driver and the current going to the LED is affected very much by the Vf of the LED. Talking to Henry at HDS, the HDS and Ra lights deliver constant power to the LED and in theory the lower Vf, the more efficient the light (so the less energy needed for any given light level. This doesn't seem to be the case w/ the Novatac. Seems like the lower the Vf, the more current the LED gets (for any given level). I know the Novatacs lack some of the efficiencies of the HDS lights, but the crazy differences in drive current for the various LEDs tested above is very puzzling!
I guess it's time to measure my HDS and Ra...stock LED vs. XP-G.
Edit: When I say, "the lower the Vf, the more efficient the light" I mean a boost converter should work more efficiently stepping up the voltage from 3V to the Vf of the LED. However, depending on the input Vf, drivers might be more (or less) efficient with lower Vf LEDs. Still, I would expect a constant current driver to keep drive levels about the same. Now that I think about it, the HDS and Ra might not be constant current, since Henry emphasized power and not current. Drive levels in these lights must be more affected by LED Vf than a constant current driver.
The madmax lite driver, for example, is a very good driver for those wanting a very efficient "constant power" driver. It is a voltage-regulated driver, but set at "wide open" mode will just deliver max power at near 90% efficiency.
OK, I'm going way off topic here and will stop blabbing.
Moddoo, what batteries are you using on the Novatac to run these tests? A 3.7V li-ion? Bench power supply? 3V lithium primary?
