Batteries: 18650 or 26650? Low or High discharge?

[gstrek]

The DGX 600 light with their single 18650 battery has a stated burn time of 60 minutes at full power and about another 60 minutes at 'gradually declining but useable light' per DGX. My other light is a Tovatec but burn time is not stated for 18650 batteries (3 hours burn time with 2 CR123).

 

[eelnoraa]

I've got 2 dive lights that use 18650 batteries, or alternatively can use two CR123 batteries. The lights are from two different manufacturers that have their own 18650 battery and charger. In order to stay under warranty, you must use the vendor's 18650 battery.

This is a bad advice in general. Although 18650 has the same size as 2x CR123, these two have different voltage. 18650 cell is nominally at 3.7V each. CR123 is nominally at 3V, so two of them in series is 6V. You will need to make sure the driver in the light is happy with 6V, not that it won't work, but there is a chance something will get damage.

 

[gstrek]

The light I was referring to ships with 2 CR123 batteries and has an optional protected 18650 battery (it is a Tovatec light). It is not my advice but the manufacturer of the light that engineered it to work with either / or. The manufacturer also states you have to use their specifically branded 18650.

 

[eelnoraa]

Understood, it works as long as the driver is designed for it.

For charger, if OP ended up with 26650, here is what I use
Review of Charger Xtar SP2

It can charge at 2000mA max. In my experience, a 4000mAh 26650 will take about 3 hours to charge. For about 2 hours, the charging is happening at max 2000mA. The it gradually drop off as the battery becomes fully charged. It will charge 2 26650 at the same time, which is the same as the 4 slots NiteCore.

LiOn cell should not be charge too slow either. In general, you want the max charging current (at the beginning) to be as close to but not exceed 1.0C. By 1.0C, it means 1x the capacity. So a 2500mAh cell should be charged with initial current close to but not exceed 2500mA. For a 4000mAh cell, the limit is 4000mA. We know this can't be possible all the time, but charging a 4000mAh cell at 500mA isn't health to the cell either.

 

[KeithG]

be careful about no-name batteries. i bought an elcheapo dive light that came with 2 trustfire 26650 batteries labeled with some unbelievable very high capacity. 1 of the batteries was DOA. so i peeled it open. It was an 18650 stuffed into a metal tube to make it as large as an 26650. i got what i paid for. they are now landfill. the elcheapo light could use either 22650 or a 18650 inside a plastic sleeve.i then bought a real dive light and now use panasonic 18650 since my real dive light is too small for 26650 batteries.

 

[MixAddict]

SubGravity did a ton of testing of commercially available 18650 batteries and the type that consistently came out on top was the Panasonic 18650 3400 MAh. We had a large order made up and branded as SubGravity. You can find them for sale here: https://www.sub-gravity.com/product/subgravity-3400-mah-18650-battery/

We have had really good success with them.

 

[tbone1004]

Panasonic NCR18650B Protected 3400mAh

identical batteries to the SG's at 2/3's the price. 4 for $66 or 6 for $60.... Not to undermine Randy et al, but just wanted to let everyone know of an alternate supply

Panasonic Lithium18650 Rechargeable Cell: 3.6V 3400mAh (12.24Wh, Button Top, PCB Protected) - UN 38.3 Passed
Also these, which have protection put in by Panasonic

 

[KeithG]

I found a cheap source of 18650 batteries...from my laptop!

I have a few year old acer laptop whose battery pack was still functional, but only lasted 1 1/2 hours instead of the 4 hours when it was new. So i bought a new battery pack for $50.

I cracked open my old battery pack and found 6 18650 batteries. New 18650 batteries are about $11 cdn plus shipping. So next time i need new batteries i will simply buy a laptop batter pack.


Curious, i ripped the pack apart (batteries where spot welded together via thin metal strips), cleaned off the sticky tape and charged the batteries. All 6 batteries ran for more than 1 hour on high in my hog edge morph. i now have lots of spare 18650s for my dive lights.

they are crg18650 batteries.

 

[tbone1004]

be very very careful with those as they do not have circuit protection on them. You have to be very careful when charging and also careful when discharging to make sure that you don't blow them up.

 

[Hatul]

I like XTAR products and my favorite charger is the VC4. It's the one I take when I travel.

http://www.xtardirect.com/collections/chargers/products/xtar-vc4-charger?variant=1059694533