Looking at the specs for the Skilhunt H04 RC, it saids it accepts 18650 as well as CR123. I read on the reviews that it has low voltage protection to prevent over discharge. Meaning not just indicate that the battery is low, but actually stop you from abusing the battery. But I’m wondering if that’s really true if the headlamp also accepts CR123 cells?
It can use 2xCR123, which means a voltage around ~5-6 volts, and would have no impact on low voltage protection for a single liion cell.
Problems do arise when the light can take a li-ion or another cell of lower voltage, such as a single CR123A (eg. Skilhunt DS10) or NiMH (eg. Skilhunt DS15). If you reset the light by opening the tail cap after it has invoked LVP on a li-ion and then retighten the cap without replacing the cell, the light may think it has been loaded with a lower-voltage cell and proceed with the LVP inactive.