Rechargable CR123 batteries: Li-ion v.s. Li-iron phosphate

Yep that’s correct, should get better lifespan out of LiFePo4s. Also, they are quite stable (much less likely to spontaneously combust), especially vs Lithium polymer batteries (which we mostly use in drones…as they have good C rating; rate of power output), which are less stable than both (I haven’t seen Lithium polymers in a CR123 or AA or similar yet, though I haven’t looked either, but don’t really know why you’d want to either…).

Some home storage batteries are happening now in LiFePO4, which is a great move. Sonnen (German) do it, very high number of cycles.

Oh yeah, another good thing about LiFePO4s are they have fewer issues with state of charge, particularly being left charged at higher states of charge. Lithium Ion and Li Polymer batteries prefer, if not in regular use, to be left at their “storage” charge level. For the polymer ones this is about 3.7-3.8volts per cell. If you leave them fully charged for too long without using them, they start to go puffy and bad (there are other ways of doing that to them as well…). Its for this reason that we’ve put some LiFePO4s in places like flight controllers where we don’t need a high discharge rate or absoluate max energy density, but not having to stress about how we recharge them to maximise their life. Just always recharge them to max after use and then put back in the cupboard. I think this is also a good quality for head torches for most people.