They donât make protected IMRâs for a reason, not âjust becauseâ.
Protection would cause significant voltage drop at high currents. Thatâs unacceptable in situations where IMR cells are used.
See e.g. NCR18650B unprotected vs protected, and thatâs just 5A:
When I got those 26650âs I was looking at putting a pcb on em, the only thing or the best thing I could find would limit em to 8A, so why bother to buy 18A capable cells in the first place?
The resistance in protection circuits depends on the trip current. Depending on chip uses they will trip with a voltage loss of 0.05 to 0.3 volt, the designer of the protection PCB then select enough fet transistor to keep the voltage below the trip voltage, until the desired trip current.
I.e. as long as the same IC is used for protection a 5A trip limit will have same voltage drop at 5A, as a 20A trip limit will have at 20A. This is probably also the reason that some protected batteries has a trip point at around 12A, instead of a more correct 5A to 7A value.
I ran one of the INRâs into a Direct drive XML P60 while measuring the current draw. I measured nearly 10Amps for about 2 seconds and the little wires in the Led melted, along with the inner part of the dome near the wires.
Drag racing at itâs finest! I wouldnât have thought that would happen, cool test. See? This is why as a noob Iâm having others mod some lights for me, I know good and well Iâd fry things! Thanks for that, sorry she went but, well, wish youâd have had video rolling!
Yeah, learning myself too. I had the Led mounted on copper, and it pulled 7Amps of a couple of other different 18650âs, so i just couldnât resist trying the new INRâs that arrived that day