18650 batteries have maximum capacities of 3400 mAH and higher. In theory, the maximum capacity of a given size battery should be proportional to its volume. So a 26650 battery, which has a volume that's (26/18)**2 = 2.08 times the volume of an 18650 battery, should in theory have a maximum capacity of at least 3400*2.08 = 7100 mAH. But in practice, the highest capacity 26650 battery I've seen is Orbronics 5750 mAH battery. What gives?
So how come 26650 batteries don't have higher mAH ratings?
- Thread starter shira
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fmc1
Enlightened
You forgot about a third very important factor, maximum continuous discharge current. If you are strictly talking capacity to size ratio probably the new Tesla 21700's are the winners. My favorite high capacity 18650's are the Sanyo NCR18650GA's. A great battery as long as you are not pulling more than 10 Amps. I know of no 18650 rated at 3400mAh or more that can deliver more than 10 Amps continuous. The Orbtronic 26650's you are talking about laugh at 10 Amps. They can give you 22 Amps start to finish and 30 Amps in bursts. Your comparison would only be valid if the maximum continuous discharge is near equal.
Frank
Frank
ChrisGarrett
Flashlight Enthusiast
Nobody cares about the 26650 cell, except for a small subset of flashlight geekdom.
No incentive to push the edge.
Chris
You are probably right but I hope it's not the case. Really like the 26650 form factor and would much prefer a single cell 26650 than multiple cell 18650 light. On some lights like dqg tiny 26650 and d4s it works so well.
Crossing my fingers we see some new ones with 7000+ mAh capacity sometime soon.
idleprocess
Flashaholic
21700 likely to be the Next Big Thing™ in Li-ion cells. Tesla is pushing them for high-cap chemistry and the power tool manufacturers seem to be doing the same on the high-current side of things; laptop OEMs have largely migrated to li-po since they've decided they can't make their products thin enough.
markr6
Flashaholic
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I'm not really gaining much from it, but I do like my Emisar D4S just as a "house" light. Something to keep in the kitchen that I don't really care how big it is (even though it's relatively compact).
I agree on the 21700. Great capacity for the small bump size. But honestly, if everything stopped at the 3500mAh 18650 I would be fine.
ChrisGarrett
Flashlight Enthusiast
I'm on the edge for the D4S, having had two DQG Tiny Triple 3 LED lights that both went up in smoke. It was a neat little light when it worked, but it ultimately did nothing for me. Still, at $48 shipped, the D4S is a way nicer light for about the same price. I just don't know if that format matters much to me?
I just got back from 21 days in Los Angeles doing home repair chores on my dad's 50+ year old house on an acre of wooded property. Everything from catching rats to watering things to working on sprinkler valves even after dark and my ET D25C Ti. clicky and 219CT D4 did the trick. Frankly, it was mostly the D25 that I carried and used, since it was easy to hold in my mouth when I needed both hands free.
Now...to have the D4S just to have, would be pretty neat, but I doubt I'd be EDCing it often...just not needed IME/IMO.
Chris
Sounds like you need a headlamp more than a D4S!
[emoji1]
ChrisGarrett
Flashlight Enthusiast
At times I did and my sister had handy her Black Diamond STORM, which she got me last Christmas, but I left it here, favoring the two that I brought with me in my carry-on suitcase. She got out her Energizer lantern and I used that repairing the brass valve, so things were good, but yes...the headlight would've worked well in some instances.
I also ended up fixing a thermocouple on their gas water heater and used the lantern, but that ultimately had a bad thermostat and we ended up replacing that professionally.
Next time I'll use the STORM more, if I don't bring my own HL with me.
For me, it's just easier to carry a small light in my pocket when I'm out and about in the garden, even in daylight hours.
Chris
idleprocess
Flashaholic
I'm contemplating 3D printing a 18650 to 26650 spacer for mine. The draw is the aux LEDs, better thermal capacity, and the better UI; I just don't use it for long enough at a time for the ~double cell capacity to matter.
The real answer is that the Chinese are currently the only ones making 26650 batteries. Their 18650's max out at about 2600 Mah's. Nearly double the size and we get about 5500 Mah in 26650 format. Want 7000 Mah 26650's you'll need Sanyo or Samsung to step in and build them.
Swedpat
Flashlight Enthusiast
Since a while Keeppower offers 6000mAh cells and I got a few of these. I like 26650 format and have several lights for that. Perfect size in the hand.
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DavisonDave
Newly Enlightened
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I have a bike light that uses a 26650 battery. It came with 2 orings to put on a 18650 battery as a spacer one at each end. You should be able to find orings at a hardware store that will work.
Nokoff
Enlightened
I have 3400 mAh 18660 batteries from like 2010 that handle 8 or 10Amps I think. Around 2012 I picked up 4Sevens protected 3900 mAh 26650s with a decent Amp drain. There were li-ion and IMR, pretty much it. So few were even making 26650 flashlights.
Now we have a bunch of chemistries to choose in both 18650 and 26650 size and we're hitting close to 6000 mAh with high discharge quality cells in the 26650. There are flashlights popping up almost daily in this size.
Cell for cell, I think 26650 growth is still proportional if not better than the 18650, much better now than before anyway.
Disclaimer: I loves a good 26650 torch
Now we have a bunch of chemistries to choose in both 18650 and 26650 size and we're hitting close to 6000 mAh with high discharge quality cells in the 26650. There are flashlights popping up almost daily in this size.
Cell for cell, I think 26650 growth is still proportional if not better than the 18650, much better now than before anyway.
Disclaimer: I loves a good 26650 torch
idleprocess
Flashaholic
WalkIntoTheLight
Flashlight Enthusiast
Or, just wrap a piece of paper around your 18650 to fit in a 26650 tube.
dealgrabber2002
Flashlight Enthusiast
I used old mouse pad. Works great.
marinemaster
Flashlight Enthusiast
There is a practical limit to EDC. 18650 in the Zebralight SC62 is as high-as I want to go. 20 years ago I had the Maglite 2C as EDC.
I have a 100 watt single cell vape box that uses the 26mm battery. It has a hohm-grown cell that touts 35 continuous and 50 amp+ pulses with over 4k mAh. Can't speak for the pulse part but it definitely lasts a lot longer than the 3000 some odd mAh factory battery it came with.
Nicotine vapes are still pushing the envelope for battery tech with those 2 and 3 (and sometimes more) coils cooking vape juice for the massive cloud lovers.
I can see a small market with flashlights, but the 18mm cell has the market sewed up for the forseeable future in my view.
Nicotine vapes are still pushing the envelope for battery tech with those 2 and 3 (and sometimes more) coils cooking vape juice for the massive cloud lovers.
I can see a small market with flashlights, but the 18mm cell has the market sewed up for the forseeable future in my view.
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