I guess the way I’ll proceed is to buy the bulk (48 cells) LiFePo4 18650 cells I’m eyeballing and stick one in my [1x]18650 flashlights designed for Li-ion and see what happens. I’ll see how long it lasts before low-voltage protection kicks in, and I may be able to live with whatever the results are, that is — if it runs at all.
See, I just really want to make an auxiliary car trunk battery out of these things, and also a handy “pocket” solar 12V pack… but I’m trying to justify them for other uses too — like my flashlights.
If its a well regulated torch that has current controlled outputs to the LED, then brightness will be the same, but these are generally found in higher price point type torches.
If its a direct drive, you can expect lower light outputs, but it should be able to maintain that until the cell is near cutoff. Deep discharging is never a good thing for the cells anyway. I personally prefer higher cutoffs to extend cell life.
If your buying these cells for other uses, then it makes a lot more sense
Got it.
So which of the Sofirn (or similar) lights in the $20-$30 range would you buy if you planned to use a LiFePo4 cell (at least some of the time, but not always), with an eye for high lumens and few modes.
I’m looking at this Sofirn SP32A V2.0 at the moment. I need one “high power” flashlight which I don’t have. I’d like to get a Q8 or SP36… but can’t really can’t justify the expense right now.
Would lights with a 6v LED be better suited to 2xLiFePos?
The Convoy L2 can run 1 or 2x18650s so should be able to handle 2xLiFePos (most likely at the expense of LVP), are there other lights with this driver in them?
Lights that can run a CR123 that have a readily available extension tube might work, such as the current Armytek lights which are designed for interchangeable battery tubes so their 18650 lights will run from a single CR123 and also from 2x18650s with the right battery tube. (There’s also a promo on until Feb 10th as advertised in this thread: ARMYTEK OFFERS and PROMOTIONS)
And you could always look at 2, 3 or 4xAA lights if you’re going up in size anyway
Very much like everything else, “safety” is in the eye of the beholder. I see no issues with using li-ion cells in flashlights or even my hair clipper without BMS (I am the battery management system). But this is me, The Battery Whisperer LoL.
Using LiFePO4 in flashlights designed with regular li-ion cells in mind won't happen without a whole new or at least reprogrammed driver setup with buck, boost or buck/boost topologies. Good luck with this.
The LD-29 buck driver is designed to drive 1S emitters and could be reprogrammed for 4V cut-off (stock features 3V and 5,8V cut-offs for 1S and 2S li-ion cells operation). Available at FastTech (take a look at the currently available coupons in the website's front page; when nothing else, “BLF” ;-) is your friend).
