Anyone know much about 18650 batteries??

[Rotaxxx]

I got a few flashlights here that need new 18650 batteries and while looking to replace them I have found some are protected, some are not. Which ones should I get? Which brands should I look at? And last but not least! What charger is the best for them? Thanks all!

 

[PeterT]

They are a different form format of Lithium Ion chemistry. So they have high energy density relative to older cells like Alkline, NiMh, NiCD. They also have a higher C-rating. That wont affect anything like a flashlight but would on any device that delivers high current relative to its nominal storage capacity (power tools). You need a charger that 'knows' this chemistry because it has a specific input voltage & ramp-up cycle. Which brands I cant recommend because they vary so much & who knows what's under the shrink wrap anyways. 90% comes from China but a myriad of grades. A lithium no-no is to allow it to drop below its terminal voltage. If it goes dead, its done. Also be aware of some Lion smart cells (or whatever they are called). I don't think they are as popular in this form factor but basically they have little on-board circuitry in the cell end that helps manages the charging & discharge duties.

Back to your basic question, I have an Amazon LED flashlight that I can either use an 1860 or 3 AAA cells, just swap out the plastic adapter. The math says Amazon Basics like alkaline cells were actually better $/mah value so that's what I run.

 

[Rotaxxx]

Thanks for the reply, it gives me something to think about, the flashlights I have are LED and are high draw ones. The one is actually a cordless spotlight, and the other is a cordless work light. The LEDs in them are single units and large, so I think they probably draw a fair amount. So I think sticking with rechargeable batteries would be best as they drain batteries fairly quick. From what I understand in your post I should get protected batteries then, and I will just pick up a charger from the place I get the batteries from.

 

[Lincoln]

Id stick with samsung and Sony cells, from my experience with the cells.
Lots of re-wraps out there, will claim more power but you peel that off and more than likely it'll be a samsung or a Sony cell.
Dewalt, Milwaukee, mikita they all use Sony or samsung

 

[Lincoln]

Go to any vape shop and pick up a charger

 

[PeterT]

I wasn't aware the proper term is protected / unproteced (what I was loosely calling the on board circuitry that you don't normally see on naked cells which is the norm.
BTW, there are all kinds of lithium flavours & also varying maH capacity for the same form factor. I've heard good things about Eneloops as another brand.
https://commonsensehome.com/18650-battery/

Generally these are in the what I would call low discharge class like ~1C. So if nominal capacity is 2850 maH, it means rated to discharge at 2.85 amps at its nominal voltage. But they have a higher nominal cell voltage (3-4v) so you are getting more power compared to a Alkaline or Ni* based cell, which is why they need to be stacked in in series. Just for side reference, hobby grade lithium polymer cells are bucking out 50-60C continuous, 100-120C burst with no end in sight. Take that Tesla. (In all fairness a fender bender would probably melt a sinkhole in the asphalt).