What are some of the highest drain PROTECTED 18650s?
Can they run an Astrolux S41, or will the protection circuit trip at the ~12A that light pulls in stock config?
What about high-drain protected 18350?
If memory serves me Tom recently got GAs with top (and protection) that were good, if so the info must be somewhere in the Q8 topic, not the easiest topic to looks in 
If I’m not mistaken, the Imalent 18650s you get with the DT70 and DT35 are protected 30Qs rated at 15A. No idea when the protection kicks in though.
I use a KeepPower protected 18650 in one of my S41:s and no problem running on turbo.
HKJ has tested them ( Test/Review of Keeppower 18650 3500mAh (Black) 2015 ) and they trip at 8.3A
According to rumour under the wrapper hides a Sanyo/Panasonic GA (plus a protection circuit)
I haven’t been able to find a protected 18350 that fits the S41; the 18350 tube is just too short.
Just curious, but why protected? What are you wanting to be protected from and why? And more importantly, why do you see it as a risk?
I use to only use Orbtronic protected 18650s when I first got into buying “real” flashlights. However, as soon as I learned that I could build one with a fet driver that could sling out a lot of light and it required unprotected cells…that’s all that I’ve purchased since. I have 8 Orbtronic protected 18650s and 4 Olight protected 18650s that are just sitting in their cases. I only use VTC6s & 30Qs for high power lights and LG MJ1s for lights that need extended run time.
Extra low voltage protection. I know the firmware has this in place, but for this particular use case I wanted a second-level protection at the cell level if possible.
LVP on a cell is what 2.5v literally pointless when it will shut itself off above that and give you ample warning before. lol
There was a design flaw affecting the first batch that could result in a short (I have 2 lights from the first batch). You can read more about it starting here: Astrolux S41 - presale ended - #398 by Kenjii
Just because you can’t think of a scenario doesn’t mean it’s pointless.
The light will be used by me 95% of the time, but there is a chance I would need to lend it out. In the case it needed to be lent out, it would be immediately with no opportunity to swap the cell, and it would be lent out for long enough that the cell would need to be recharged. So yes, I want to keep a protected cell in this light as a secondary layer of protection, despite the fact that the light has LVP.
Not sure that warrants a protected cell though.
I have some EVVA NCR18650BD 3200mAh protected batteries, works very well in my high drain flashlights.
EDIT : Just tested the battery in a Convoy M1 quad, on a Sony VTC6 it pulls a bit over 20 amps, on the EVVA it pulls 10,7 Amps
when mod a light, especially when using many wires in your light( driver mod, stack IC, etc) or your output to led accidentally touch the reflector and, KA BOOM, your driver is fried
Protected cells won’t help you there though, that’s not how they work.
I assume that they will cut off the energy when they detect short circuit
So, the driver won’t be fried(especiall direct drive driver)
And if you use constant driver, there is no problem then
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 on my S41, though, because the stock S41 is already close to tripping a 10A protection circuit.
Do you know what amps it actually pulls though? Batteries might be ‘rated’ for an amp draw, but it doesn’t always mean they actually deliver it in practice. Not saying yours isn’t, just curious.