18650 batteries: what's your go to

[tbone1004]

Per above, Panasonic cells. Not just Amazon though. Lots of fakes. Mountain Electronics is a go to for the folks on Candlepower Forums and has been good for me and authentic stuff.

I did side by side rundown tests on Dgx600 and got meaningfully better times vs the 2400 or 2600 mah that came with them.

I use protected cells mostly. But, if I were a cave guy and these were critical backups, I'd use unprotected. If I really needed it, I'd rather not have it shut down when voltage drops. I wouldn't really care if I trashed the cell in that scenario. I'd rather have 10 more minutes of fading light.

eh, I have protected cells in all of my lights. Just carry an extra one. I plan my backup lights at how long my gas can possibly last me, then add a bit. I know my backup lights burn for 45 minutes, so if I have a 1.5 hour exit from the cave, I carry 3 etc

 

[JohnnyC]

I use normal alkalines in my backup lights. It's just easier to not have to think about them. You can get them anywhere and don't need to worry about battery maintenance like a set of rechargeables.

For any lights that use an 18650, I use protected cells. We know how to exit caves in zero viz, so having backup lights shut off isn't really a huge deal. Lithium chemistry batteries do funny things when they're outside of their designed operating window. I would rather have a battery that shuts off safely, than a battery that may act unpredictably. Of course this is all predicated on having 6 (or more) full light failures. Statistically it's pretty unlikely, so in terms of safe diving, you're actually far better prepared in a cave than a recreational diver doing an ocean night dive with a single light source.

I would be far more concerned about having a battery issue due to an unprotected 18650 in a recreational, ocean setting than anything in a cave.

As far as buying batteries, stick with a major manufacturer (LG, Sony, Panasonic, Samsung, etc.) from a trusted supplier, and you should be fine.

 

[asher102]

The LG HG2s are great 3000mAh cells. If you want more information on 18650s or 26650s Google "Moochs battery chart", the guy does a great job of exposing ****** cells. As for purchasing cells I have always like www.illumn.com

 

[Brian G]

The key is that you need a trusted supplier. Amazon is NOT one of these. "Panasonic" batteries from Amazon could be anything. The big three have already been listed. Liionwholesale.com, illumn.com, and mtnelectronics.com. Liionwholesale.com indicates that they test a sampling of every batch they get in. I'm not sure if the others do that, but they have been trusted for years. Testing is the only sure way to know if you have authentic cells, so I do liionwholesale. Sometimes they don't have what I need in stock though.

 

[Jonny Wishbone]

batteryjunction.com

 

[Schwob]

If you already have a bunch of still working "elCheapo" 18650s (occasional use only, none used a lot), how do you:
- tell if one is protected or not?
- test to see if it is a decent battery at this time (longevity may be an entirely different issue) and maybe determine actual capacity (w/o ruining it in the process)?

 

[tbone1004]

@Schwob
1-it will have a protection circuit on the top. You can usually visually ID them, but if you post some pictures of the + end, we can help you out
2- need a charger/tester of some variety to do it properly
I use this one. Does NiMH as well which is nice for my AA and AAA batteries, but it will cycle them and tell you how many mah it will discharge.
Opus BT-C3100 Charger/Battery Tester
This one is a bit more advanced, but obviously significantly more expensive
XTAR Dragon VP4 Plus Battery Charger/Tester

 

[Brian G]

The protection circuit is an 18mm round board that is at the top or bottom of the battery. This site seems to be pretty clear - The Anatomy of a Protected Battery. Battery chargers like tbone mentioned will test the capacity at moderate current draw which should be fine for dive lights.

 

[kelemvor]

Just get them from old laptops. You'll need a pair of needlenose pliers, a regular pair of pliers, and maybe a flathead screwdriver (for prying). I've had batteries come out of laptop packs that were kaput. I've had others that held 2800mah. Most are somewhere in between. That's about the same track record people seem to have when ordering batteries "new" from some place.

I do have a couple of "UltraFire" batteries that someone gave me with a headlight as a gift. Those bad boys come in at a whopping 1400mah. They have the extra length of a protected cell, but I've never actually disassembled them to see if they really had protection.

Usually you get "flat top" cells from laptop packs. A bead of solder on the end makes them into a "button top" just fine.

Here's a Sony cell that came in at just over 2400mah from a laptop pack. I added a bead for the button top onto this one. Works fine, lasts long time. Cost: $0.00

 

[JohnnyC]

Be VERY ******* CAREFUL salvaging batteries from laptop and power tool battery packs. It's not difficult to damage the wrap, short things, damage terminals, etc. and end up with a lithium fire on your hands. And taking a soldering iron to a battery to add a button top is risky. They are not designed fo operate in high temperatures, and it's quite easy to damage them to the point that use can be dangerous.

Seriously, be careful.