Comment by walrus01

So I was referring specifically to this phone hardware project and to flashlights, which don't fly... But my thoughts on drones are also that it's very different if you're building consumer class things that are meant to be re-used or what's going on in ukraine right now. They're using high amp rate cylidrical 18650 and 21700 cells in 6S2P and 6S3P packs for one way trip munition drones where you don't particularly care if you damage the li ion cells for any future re-use. In which case in the last few minutes of flight you can abuse the hell out of them with high amperage draw down to 2.5V (but beware of extreme voltage sag at the bottom end) and never have to worry.

If we're talking about something that's designed to be re-used then a totally different set of design considerations, as you outline above, become applicable.

> Frequently , after a hundred (or often much less) cycles in a MUAV a battery is retired from stressful missions

Are you talking about lipo pouch cells or li-ion cylindrical? Because if we're talking about state of the art high amp draw rated li ion cylindrical cells, 100 cycles on something that isn't heavily abused for heat and doesn't go below 15% state of charge should not significantly affect its lifespan. But if the batteries are being abused or every last bit of margin on range/payload is needed that it calls for almost "factory fresh" cells, or there's just absurd amounts of DoD money to throw at buying new battery packs, sure, I guess.