So people throw out disposable vapes all the time. I cracked one open to take a look and it turns out they have a 18500 battery in it. So I was thinking of 3D printing a spacer to make it the same size as a 18650 and putting some shrink wrap on them. I just wanted to see what people who know more than me think. Is this a bad idea that is going to burn my house down? a waste of time perhaps?
I did a trial run in my wurkkos fc11 and they seem to work, it charges and looks just as bright.
The protection circuit of a cylindrical Li-Ion battery doesn’t report anything. All it can do is to interrupt the circuit if the current gets too high or the voltage too low.
You might mix this up with tool batteries that usually have multiple cells in a series and in parallel, monitored by a battery management system (BMS).
Most quality flashlights have an integrated low voltage protection. The protection PCB will only protect the battery when it’s handled outside of the flashlight, but it will usually reduce the performance and efficiency due to the added resistance.