I know what you are saying but surely if I buy 2 cells, mark them & make sure that I alternate which one gets used in the Cometa then wear on both cells should be similar shouldn”t it ?
I am quite careful with my cells & do check them regularly with a DMM & have an analysing charger.
No. There are far more variables to consider than just usage time or remaining voltage. The more the cells are used apart from each other the closer to a potential failure you come. And a failure with a Liion cell can cost a heck of a lot more than the $10-15 saved by not buying an extra 26650 cell.
Fair enough, do you have any recommendations for suitable cells for my use that I can either get here in the UK or have delivered to the UK that cost a reasonable amount ?
My nearest supplier charges £17 or $25 dollars per cell.
Torchy on Ebay has some 26650 at £16 for two delivered. Thats where I’d get them from.
That I can’t help you with. Here in the US I imagine liion cells have similar prices in like a vape store or similar shop (I’ve never had the need to buy local liion cells so I don’t know for certain)… Anyway, if you can’t find good prices local or have a great option like mtnelectronics, for fair prices and variety you might have to choose a source like Banggood or FastTech, maybe eBay.
Well I have been emailing Thorfire & they state that their 3000 mah 18650 cells are indeed Samsung cells (although they didn”t confirm that they were 30B”s) but they state that their 2200 mah 18650”s, 14500”s & 26650 are their own cells made in their own factory ?
Have you checked eu.nkon.nl? They have a variation of Li-Ion’s.
Only suitable cell they have around 5000 mah seems to be a Keeppower which is over £14 or $20 dollars per cell delivered.
They do have an Efest 5200 mah cell a little cheaper (about £11 or $15) but it states it is flat top & dosen”t look like it will work in series ?
I will pull the trigger on some cells tonight just still unsure what they will be 
I am also buying the exact same lights when available, was wondering if these will be ok ? Basen IMR26650 4500mah, seems like a good price. ENDED
Will purchase 3 or 4
Thanks
I’m also in a state of analysis paralysis over which cells to purchase for the Cometa (I’ve posted a few other questions on that specific thread).
I’d prefer protected cells, but have not discounted unprotected cells.
I’d prefer 18650s so that I can swap the cells with my other lights (and more “quality brand” options), but also like the increased run time (and current draw) of the 26650s.
Decisions, decisions!
Would there be a realistically noticeable difference in brightness between using a protected and unprotected cells (e.g. Keeppower 26650 5200mAh protected vs Keeppower 26650 5200mAh unprotected) when using the highest high, and turbo modes?
I have Enerpower 4700 and I am happy with them.
Even if they are flat top, they work OK on my ThorFire S70. No need to use magnets.
Whatever cells you go for you will need quality cells, quality charger & IMO a DMM.
Couple the above with a light that has low voltage protection/cut off & I really can”t see the problem with using unprotected cells.
You probably have more chance of being run over by a bus than having a dangerous event with the cell.
In fact the more I have used Li-ions I have moved away from protected cells just about all together.
For a high draw light like the Cometa I would definitely go for 26650”s over 18650”s.
Whether you would actually be able to see a difference in light out put between the protected & unprotected versions of the Keeppower with the naked eye I don”t really know, other more knowledgeable members will be able to comment.
The unprotected version is rated at 15A constant draw & 30A pulse, the protected is rated at 9.4A before the protection kicks in.
The Cometa is stated to have a draw of 5.5-6.0A on Turbo & I always try to use a cell that is rated at at least twice the max draw amps of the light to try to give the cell an easier time so for me I would not use the protected version.
I have chosen the unprotected KP”s for my S70, which has a similar draw to the Cometa, based on a slight trade off of max amps versus run time & will be using the same cell in my Cometa.
In the S70 the unprotected KP”s give me a tail cap reading a little over 5 amps (5.24A to be exact).
The 4500 mah Basen cell, for which there is discount code available, has shown a 5.44A tail cap reading for members with the same light (S70) so would be another cell to consider for the Cometa.
The Heter 4500mAh 26650’s are a terrific deal at GearBest; also available at Banggood. “3C” rated (13’5A continuous).
Interesting information I found about ‘em in Cervantes’ language (my native one): Heter 26650 4500mAh detailed manufacturer specs (and more) @ForoLinternas
These are on my wishlist.
Cheers
Thanks for the recommendations.
I think I’m now erring between 3500mAh NCR18650GA based cells (for sharing with other lights) and/or the Keeppower 5220mAh 26650s for the Cometa.
Whilst I trust myself with unprotected cells, I have 3 young kids in the house who sometimes meddle with things they shouldn’t be meddling with. Whilst I keep the cells, flashlights, and charger out of their way, you never know what can happen.
Are there any online comparisons between the protected and unprotected Keeppower 52200mAh 26650s?
Hi stephenk, have a look at the graph on post number 33 Basen 26650 4500mAh Issue ?
There is a very good performing 18650 cell, an LG HG2, tested alongside 26650 cells for comparison & you will see that it does not perform anywhere near as well as a good 26650.
For a single cell light drawing 5.5-6.0A like the Cometa I personally would not use 18650”s.
This link will show you a comparison of the protected & unprotected KP”s Battery test-review 26650 comparator
just choose the cells from the drop down box.
If you click where it says “see test/review” under the cell description it will give you the complete review of that cell.
The 2014 version is a test of the protected 5200 mah cell & the 2015 version is of the unprotected 5200 mah cell.
Thanks, much appreciated. I didn’t realised the 2014 version was the protected!
I think that it is just that HKJ tested the protected version in 2014 & the unprotected version in 2015.
Either way both versions are available now.
I still think that an unprotected cell is better for a high draw light like the Cometa which has low voltage warning/cut off but obviously only you can make the decision.