One more twist on 18650s / UF10….
Put the driver at the tail.
Then make a smart tailcap board and put it on the front.
Now the light can have:
RGB aux LEDs with voltage indication
thermal protection
Thermal protection … interferes with modes of the actual driver. It’s no easy to do it well. One could envision the front driver communicating temperature to the tail driver by manipulating the current that passes through the circuit somehow. It’s not easy.
Or it could just regulate by itself, leaving the tail driver at whatever mode it had. It’s very ugly and inefficient.
With both drivers being constant-current they could actually negotiate with one hard-clamping current and the other noticing that.
But it’s simple to make thermal protection good enough to be viable - just treat it as a protection feature and do a hard shutdown upon severe overheating.
Driver-in-tail designs (eg, Luxpro 2×D lights, as well as some “better” zoomies) do this. Usual way to distinguish them is a light-touch switch, not the usual angry-clicky types.
The driver-in-tail naturally interrupts the current flow for a very short time, just enough to let power flow into the driver board. Think of it as ~99% PWM maximum. Big honkin’ FET does the interrupting. Also PWMs the current to the LED accordingly.
Here and I thought my snap in 26800 battery was revolutionary…. :cry:
