Which 18650 Battery to use

azufelt · Jan 21, 2009

First time poster: I am getting ready to purchase a Fenix TK11 R2, batteries and a charger from Battery Junction. http://www.batteryjunction.com/r2-fenix-tk11-r2.html

I am considering two offered brands of protected 18650 cells. The first is a Tenergy 2600 Mah (flattop) and the second is an Ultrafire 2400 Mah (buttontop). I don't know enough about the difference between the two different styles of batteries to make an informed decision. Additional considerations: I may later add a Lumapower MRV SK Ultra or a Lumapower MVP (Unlike the Fenix, these take two batteries stacked) I would prefer to use one battery type for all if possible. I like the 2600 Mah of the Tenergy, but does it matter if I use buttontop or not?

coppertrail · Jan 21, 2009

I own both the Tenergy and Ultrafire 18650 cells and have replaced them with AW cells :) Actually, I still use the Tenergy cells in my Lumapower MRV and they work fine. Are they actually 2600 mAh? I highly doubt it.

I'm pretty sure you want the button tops since you won't be using them in a pack/series.

Fallingwater · Jan 21, 2009

Do not buy Ultrafires. They are known to be dodgy. Buy Trustfires if you can find them, otherwise other brands. Or AWs if you want the best (and most expensive) 18650s available.

kfallscody · Jan 21, 2009

I personally would go for the button top regardless of use. The flat tops are generally better suited for making battery packs where they are soldered together.

As a side note, I purchased 4 of the Ultrafire protected 18650's about a year ago. As of today, only one still works and has about 1/3 the capacity of the AW cells I purchased to replace them. The three that failed completely, did so within 2 months of purchase. The AW cells have been going strong for about 10 months now with no issue. Just food for thought :)

VegasF6 · Jan 21, 2009

I don't think it is fair to refer to AW cells as the most expensive. Of the ones mentioned, yes. But, they are less than Pila or Wolf Eyes, and of the 3 quality made protected cells availible they are the cheapest.

Now as to what is better between ultrafire and trustfire, well I have actually had better experiences with the ultrafire. But, that's just me.
Personally, I had terrible luck with my tenergy's as well, but that may have been user error, they were unprotected cells.

I will point you to this thread however:
http://www.candlepowerforums.com/vb/showthread.php?t=189738

I did find this quote interesting :)
http://www.candlepowerforums.com/vb/showpost.php?p=2361422&postcount=2

mdocod · Jan 21, 2009

Fallingwater said:
Do not buy Ultrafires. They are known to be dodgy. Buy Trustfires if you can find them, otherwise other brands. Or AWs if you want the best (and most expensive) 18650s available.

While AW cells are some of the best, they are certainly not the most expensive. To put things in perspective, please look at Pila cells.