I was first introduced to 18650 cells a bit over 10 years ago after winning my first “karma” on SigForum.... a Fenix TK11 tactical flashlight. It was designed to use either two CR123 lithium batteries, or a single 18650 rechargeable battery. I quickly went rechargable, but have since learned there IS a difference!

A year or so ago, after deciding my original 18650’s were worn out, decided to buy replacements from my local “Batteries+Bulbs” store. While a name-brand, they were a touch too large in diameter to fit in my TK11 flashlight. I quickly realized I could remove the outer shrink-wrap skin and they fit perfectly.

Fast-forward to last week when I received a Feyachi weapon light for my AR-15 that included two new 18650 cells, and I realized they were a shade too long to fit my existing battery charger...

Since the WML included a new charger for the included 18650 cells, it was not that big of a deal; they were easily charged, just not with equipment that I already owned.

So please beware... if you already own 18650 cells, there is a decent chance that they will NOT fit your existing equipment without modification due to variances in the product!

Cheers...

Stay (far) away from any with fire in the name. I like and use the Orbtronic protected 3500 mAh. I've been using my XTAR VP2 charger since I got it in 2015.

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“Protected” cells will have a small circuit board attached at the negative end of the battery to protect it from over discharge (which will quickly kill a Li-ion battery) or a potential runaway reaction when run in series with another cell with a different discharge rate due to a defect or age. The board adds a little extra length that can affect fitment or be slightly wider than the battery, doing the same.

I have been scrounging 18650 batteries for years from old laptop battery packs. Most of the time it is internal electronics that go bad in them, or one or two batteries of the bunch. If your device does not have a built in low voltage protection circuit, running them below 2.7V will vastly shorten their lifespan so you have to monitor usage and switch them out accordingly. If you accumulate a good number of them, killing one here or there isn’t a big deal. Almost every laptop battery has quality cells from folks like Samsung, Panasonic, Sony, etc.

I actually did a tutorial on the forum on how to harvest battery packs for working cells but it seems to have dropped off.

 
I've noticed that most of the rechargeable battery packs for cordless tools are moving to the 21700 cells, larger diameter and length for holding a charge longer. And for some reason, the Bosch 4Ah battery packs with the new cells are smaller than the 4Ah packs with the 18650 cells.

My go to 18650 charger is a Nitecore F1 which adjust for most any length 3.7v battery. I like it because I'm using a lot of unprotected Panasonic and Sanyo batteries (15+ years old) as well as newer batteries.

When I first read the title of the thread I thought it was going to be about different Li-Ion chemistries for 18650s like Lithium Cobalt Oxide, Lithium Manganese Oxide, etc. and the safety of one over the other.

I've never had a major problem with any quality 18650 battery thus far and I'm sure I'll still be using them long after the 21700 renders them obsolete.

One of my Fenix lights (I think it’s the PD35) has a magnetic charging cable on the body, so you can just leave the battery in and connect it.

So, I just charge all of my 18650s with that flashlight. Real easy.

quote:

Originally posted by BlackTalonJHP:
My go to 18650 charger is a Nitecore F1 which adjust for most any length 3.7v battery. I like it because I'm using a lot of unprotected Panasonic and Sanyo batteries (15+ years old) as well as newer batteries.

When I first read the title of the thread I thought it was going to be about different Li-Ion chemistries for 18650s like Lithium Cobalt Oxide, Lithium Manganese Oxide, etc. and the safety of one over the other.

I've never had a major problem with any quality 18650 battery thus far and I'm sure I'll still be using them long after the 21700 renders them obsolete.

I have an older version of the Nitecore i4 Intelligent charger; the really cool thing about this type of charger is that you can charge any type of rechargeable battery that will fit into it regardless of chemistry. You can charge Li-ion, Li-po, Ni-mh, Ni-cad, even side by side. Each battery bay will read the battery type and charge it accordingly.


https://www.18650batterystore....ct-p/nitecore-i4.htm

+++ For the NiteCore Charger.