Yep, I canāt find it now, but I believe the input voltage is 5-8.4V for the lights.
USB 2.0 supplies 0.5mA max, so x2 is ~1.0A. Safety factor of AliExpress, we can assume 2.0A is possible max current draw. Some of those Ali listings also sell a 2s 18650 pack for bikes, intended to be powered directly from the battery at 8.4V, so that checks out.
Thatās how I sized the buck. Itās output voltage is adjustable, set to 5V now. Increasing that voltage may allow the light to run cooler (& the buck more efficiently). It can provide 1.5-3.0A.
Buck input voltage is claimed to be 55V (60V on some of the LM2596hv). That should be enough head room for a fully charged 12s pack.
Iāll do some testing, and try adjusting the voltage up to ~8.0V and see what changes.
@Toughook is running them at 8.4V, maybe he can chime in on performance so far.