1

In the 18650 format, the Samsung 30Q has been popular because it is a happy medium of relatively high current, decent capacity, and good pricing.

Does the Samsung 40T meet the same criteria for 21700 or do you prefer another cell?

2

The 30Q is 3000mAh and 15 amps. A 21700 is 1.46x bigger than an 18650. So a similar 21700 should be around 4300mAh and 22 amps. The 40T falls a bit short in capacity and has substantially more discharge.

For flashlights we typically value capacity above discharge. Offhand I don’t know of anything that needs 30 amps and has a replaceable cell. Nitecore’s 10K lumen light almost counts but its 21700 is hardwired.

Looking through my battery database there is a void in the market here. They mostly for power or for energy. Very few 21700 between 4Ah and 5Ah.

I think the Lishen LR21700SF might be the best cell in this tiny middle ground. 4500mAh capacity and a 13.5 amp discharge for only $6. But I don’t think anyone has tested them?

3

About the only 21s I have are Sofirn cells, but I’m not sure what’s under the wraps. Either way, they’re perfect for my C8Fs and similar.

4

The 40T is really good, but I think the best balance would be at a higher capacity and less current capability. Maybe we will get a cell at 5Ah with around 15A discharge in the future.

5

Anyone recall offhand what the blue LK 26650s do? Think 5000mAh, but dunno the max drain.