I make current measurement today. So far after playing with flashlight for entire day, no problem yet!
For low values, I use multimeter in Amps setting. For turbo mode, I use wire and extech clamp meter (but 2.5% error+some digits). Battery used is LG HG2. I also solder J1 and J2 to test turbo mode at 5.5A. Default turbo mode is 5A. According to Loneoceans current chart of current to 6V LED, here is the tail-cap current I measure:
- Moonlight (<10mA) - 12mA
- Candle (no rating) - 20 - 40mA? Jumps around
- Low (50mA) - 72mA
- Med (250mA) - 390mA
- Bright (1A) - 1520mA
- Turbo (5A) - 11.2A (clamp meter)
- Turbo (5.5A) - 12.4A (clamp meter)
Be careful - tail current only applicable to my battery, if you use better battery, current may be less. It seem like with changing resistor or firmware, much more current can be achieve!
However at 4V battery voltage, 12.4A is already 49.6 watts!! Please let me know if anyone want to know more test.
Overall this was very interesting project to solder. Although I have soldering experience, Gxb172 was still difficult to solder together, but easier with practise. I recommend using usb microsocope or magnification during soldering, very small solder tip, very thin solder wire, and hot air. For mistake, thin solder-wick is the best.
I also suggest using flux pen and needle tweezer. For cleaning, I use cleaning alcohol and cotton swab. Solder for temperature IC is most difficult because it is very small, so I suggest using no solder, only flux. High heat and low air speed. Inductor is hard to solder, but just keep at ~270C air heat for a while and it will solder.
Finally, before assemble I suggest to test with multimeter to make sure no shorts, then test before putting into flashlight host.
For program, I don't know of easier way than using pogoprog, but you can also use thin wire soldered to programmer. I use Atmel ICE, so I have no idea about USBASP, but moderator007 has used it to program so it will work.
Difficulty - 7/10
Cost - 8/10
Brightness & result - 9/10
I hope to be able to get firmware to change for even more current, or I may have to do resistor mod