In just the last few months, new LED’s were introduced for flashlights by the company Cree. Cree assigns bin numbers to LED’s that indicate how bright they are. All of my newest lights have various Cree LED’s and bin numbers. The Fenix is XR-E LED with a Q5 bin. The tiny flashlight is a XP-E LED (smaller than the XR-E) with a Q5 bin. There isn’t a Q6. For whatever reason, the next level of brightness is R2. The stainless flashlight I just got has an XP-E R2 LED, but I couldn’t tell that it was brighter than the Q5’s. Now there is a new LED called the XP-G which has bin numbers as high as R5. That should be significantly brighter. So I went looking around for cheap R5 flashlights, but couldn’t find any. For whatever dumb reason, I wound up buying an R2 LED that promised to be 250 lumens (my brightest is 180 lumens), not thinking that that probably wasn’t even possible with a R2. Worse, I bought a 6-mode flashlight with 3 different flashy modes (fast strobe, slow strobe, and SOS) and I didn’t realize that the light wouldn’t accept lithium-ion batteries which are the only way to get significant brightness out of a 1xAA light. So it showed up yesterday and it was a kind of decent light. I posted a review with all the details. Anyway, I didn’t like the light and the only way I was going to like it was if I could make it brighter by using a lithium-ion battery, so even though you aren’t supposed to use one, I put one in there anyway. And the light wouldn’t work anymore. I had burned it up. I didn’t even have it a whole day.
But as it turned out, the “driver” which is all the electronics in between the battery and the LED that give it the modes and provide a uniform voltage had burned out. The LED itself was still working. And the switch was still working. These LED’s need 3.6 volts to light up. So a 1xAA flashlight has to boost the voltage up to that level. But a lithium-ion battery is already 3.6 volts. Most lights that use a lithium-ion battery still regulate the voltage so that the brightness doesn’t fade as the battery voltage fades, but you can also “direct drive” a LED. So I found the wires leading from the LED and soldered them onto some plates that were connected to the positive and negative ends of the battery. It didn’t work, but I think that was because of my lousy soldering. I fiddled with the soldering and I would get just a flash of light every now and then. So I fiddled with it some more and now it works! So I have a 1-mode direct drive light. It won’t work at all with an AA battery, but it is quite bright with the lithium-ion battery (maybe my brightest light). So that’s better than nothing.