If they free fall that far just sitting you've got some seriously dead cells there I'd toss them . They say if the fall 20% from a full charge just by sitting it's clear indicator that they are toast .
I've brought back and used batteries that have voltages below 3 volts but I've never kept anything that fell on it's face that hard . second test is how well it handles a serious direct driven light that is extra amp hungry..noting initial amp draw and then how fast it drops before it stablizes and then comparing the numbers with like cells ...apples vs apples .
If a battery doesn't fully charge up to 4.2 that's not a good sign either .... There are lots of free cells out there ...Too many to be messing around with trash.
Until I had really good cells I never realized how bad most of mine were .
If you're not is the U.S. I'd buy from Efest
In the states..kumabear
It's odd that people who want the biggest badest brightest light then go and buy crappy batteries that can't deliver ...if you want output you have to give it real input .
The more 18650s I get, the more I can tell which of my cells are not up to snuff. I believe I might have a Bogus Ultrafire 18650. I got it new from DD but it doesn’t hold a charge like my decent laptop cells.
At least with harvested cells, you know what you are getting is indeed real. All you need to find out is what kind of condition they are in. With the crappy xxx fires, you might even be getting a li-on cells at all.
Makita got such a bad rep from people that abused their batteries. I frikkin’ love their products and the torque these batteries deliver can’t be beat. I’ve got some cells I scavenged from the first two packs I bought 7 years ago and they out-shine everything I’ve tried.
On the other hand, I have @200 of the red Sanyo’s I’ve collected from Dell packs. Some I’ve been using as cells for over ten years and before I had any clue how to maintain them. Not much power but decent capacity and after using so many of them and seeing them all perform exactly the same over and over and over, I consider them as safe and durable as you’ll find. I usually leave them tabbed so I can easily rack and stack ’em for all kinds of fun projects.
those cells surely may not be perfect, but they get the job done.
I have kept one in my L2P-M3 (replacement M3, first one got stolen :cry:( ) for the past three weeks, and it still lights up fine.
As long as those cells deliver what I am expecting from them (several three-second blasts, and maybe ten minutes at high, per every evening) I am happy. Better to use them up. In the end, I’ll have them recycled, anyways - why not make some good use of them while they last?