18650 Suggestions - Help! I’m Very Confused!

Hi All!

Thanks in advance for helping out! I'm brand new to the forum and brand new to using 18650's in lights! Ive been using CR123's in all of my lights for ages... and spent a small fortune to keep them fed. Finally decided that it was time to move to the rechargeable world. I've done some research, but all the theoretical info is making my head spin! I'm hoping y'all can help me out a bit.

So here's the situation:

I recently purchased a Nitecor D2 Charger, along with 2 KeepPower protected 18650 Li-ion cells (3500mAh, 3.7V, 12.95Wh, Part Number - P1835J)

I have a few flashlights that I will be using them in:

Streamlight ProTac HLX (Mounted to a firearm)
Fenix PD-35 Tac
...and another one that I cant remember off the top of my head right now.

The question is this: What battery would you recommend. Ive heard so much about protected vs unprotected, stability vs ruggedness, power consumption, etc, that my head is spinning, and I'm not sure where to even start.

What I would like to ultimately have, is several affordable 18650 Cells that can function in rugged environments (I'm not easy on my lights, they get dropped, stepped on, are firearm mounted, etc), give good light performance (output, runtime, capacity, etc), and be safe doing the above (don't want it exploding in my bag)

Budget is a bit of a concern, as right now I'm not made of money and am looking to get several.

What recommendations would you have! Thanks so much in advance!

-Josh

Hello Josh,

Welcome to CPF.

Research will give you specifications on the performance of many cells. You can search for tests run by HKJ and visit his web page for more information on specific cells.

Protected versus unprotected depends upon how much effort you want to put in and how much risk you want to take.

In critical applications I prefer unprotected cells. The protection circuit is one more thing that can fail if the cells is dropped or treated roughly. When I loan a light to someone that doesn't know anything about batteries, I hand then a light with protected cells. This adds a layer of safety.

As you can see, there is no single answer. The best advice is to use quality cells.

Tom

Welcome!

Your keepower are good cells. As mentioned their protection circuit is another potential failure point. Most folks will suggest not using those in WMLs and to use primaries.

For anything that is mission critical primaries are preferred by the vast majority. Some also use unprotected rechargeables.

For 18650s, unprotected cells can be just fine and I use them more than protected cells. It is good practice to buy quality cells. If you are planning on running a light with 18650s in series it is safer to use protected cells. If only using one, most lights will dim noticeably when they require charging.

As mentioned HKJ has done a lot of research on different cells and his website contains a ton of information on them to see what meets your needs.

If you don't plan on buying a multimeter for checking cells, and keeping fixed pairs together (bought, checked, used, charged, checked...together), I wouldn't suggest running unprotected cells in sequence. Just to be safe.

That being said, cells from reputable manufacturers; Sanyo, LG, Sony, etc are generally good bets. Protected cells of high quality are generally re-wrapped name brand cells with a protection circuit on them.

Buy cells that provide the capacity and/ or discharge rate you require.

There is a lot of info on this topic on the forum.

Welcome again and good luck!