I don’t have much experience with protected cells. Don’t most protection circuits trip at single-digit amperage? Do they actually trip at (let’s say) 6A, or are they just restrictive and tend to reduce the current capability of the cell to 6A?
I think the S41 draws about 10 or 12A stock if I recall correctly.
What (if any) protected 18650 could handle that?
And this may be a stretch, but could any protected 18350 run that light?
I’m using an EagTac 3.7V 3500mAh protected 18650, which is rated for 10A, and that works fine. I deliberately didn’t do any spring bypasses or suchlike, though, because the stock S41 is already close to tripping a 10A protection circuit.
I don’t use 18350 cells at all, so I can’t comment on those.
Are you sure the S41 draws 10 to 12 amps? It only has 4 emitters.
My DQG tiny has 7 and puts out 2500 lumen. Normally it pulls 6 to 7 amps on turbo, but with lower voltage it might pull 10 amps.
I’m currently using a protected 18650 (Keeppower 3500 Sanyo ncr18650ga) with 8 amp ability (while I wait for my liitokala 26650 to arrive) and it’s working fine. Once the battery gets down to 3.6 volts I’m either getting voltage sag tripping the lights low voltage protection (preventing use of turbo) or the batteries protection circuitry is kicking in and doing the same. My light just turns off completely if I use turbo, so it might be the battery.
So if you use the same battery you’ll probably have turbo down to 3.5v or 3.4v I’m thinking.
Of coarse, an unprotected battery might allow turbo down to a lower voltage, but due to voltage sag, the light might prevent turbo usage.
Protected 18350 batteries are rare. Due to small capacity, I would not use them on a powerful light. They just don’t last.
I’m using that KeepPower cell in one of my S41:s and it works fine.