Ultrafire UF10 and UF9 have Drivers in the tail and they are my coolest 16340 lights. You can drill the tube to fit a 18350, I made it on three lights.
Robert
An illuminated tail cap is literally just another LED in the circuit, that’s why it only needs to be in line to work.
For any kind of modern not-super-basic driver there needs to be separate positive and negative to both the driver and LED for it to work properly.
Stuff like LVP, battery indication, cc regulation, etc…
That stuff is not possible if you simply have battery~~driver~~>led->battery.
In this case the driver would literally just be an in-line resistor, it would not have any other functionality.
With our drivers the battery positive does “pass through” to the LED, but it’s still connected to the driver. The MCU needs the connection to the positive to work.
So it’s impossible to have a driver without +
Technically you can, it would basically be the same thing as a resistor.
Maybe it would be possible to have it switch between different resistances too to change the brightness.
But for most drivers, the advanced kind we use in flashlights, it would not work (not properly, at least) if you connected + directly to the LED bypassing the driver.
“just another LED in the circuit” still requires Pos+ and Neg- just like a full driver does.
As I quoted in my post LVP would be difficult to get accurate, and I agree with all of your Pos+ running throught LED the LED would have to be on for the driver to be powered, but this is currently true of clicky lights anyways. This configuration would not work for a an e-switch driver, granted.
I mentioned the illuminated tailcap because I was met with the same resistance with it “It’s not possible, it won’t work” even after it had been proven to work.
We already have existing lights with the driver in the tail and no additional wires, so it’s ignorant to still say “It’s impossible!”. It’s just a matter of “how much do you want it?”
drivers in tail without double tube or wires
or special battery with both battery contacts to tail
the lights from Imalent have big drawbacks
first 33 Ohms bleeder resistor, jes 33 no 0 missing, so in lowest mode the bleeding current is on a normal Vf of the LED a bit over 100mA
2. slow PWM at 400Hz even at full brightness to power the driver in the off time
this pwm can be noticed by eye in multiple situations
3. LVP is almost impossible to do in the Off time, because it may be tricky to sense this while the inductor is draining power through the bleeder, to drive the MCU during on time