Test/review of Keeppower 18650 3500mAh P1835K (Black) 2019

Keeppower 18650 3500mAh P1835K (Black) 2019

Official specifications:

  • Capacity min.: 3350mAh

  • Capacity typ.: 3500mAh

  • Nominal voltage: 3.70V

  • Charge voltage: 4.20+/-0.05V

  • Standard discharge cut-off voltage: 2.50V

  • Standard charge current: 1700mA

  • Charge termination current: 50mA

  • Max. continuous discharge current: 8A

This is a 3500mAh protected 18650 battery from Keeppower.

The two cells match very nicely. At continuous 7A the protection trips before the batteries are empty.


This is very good quality protected batteries and one of the highest capacity 18650 batteries available.

Notes and links

The batteries was supplied by Keeppower for review.

How is the test done and how to read the charts
How is a protected LiIon battery constructed
More about button top and flat top batteries
Graphical comparison to 18650 and other batteries
Table with all tested LiIon batteries

Considering this is (assumingly) a 10A battery underneath, I’m a little disappointed that it tripped at 7A, especially since it’s claiming 8A continuous. They should have programmed it to not trip until 9 or 10 amps to get more possibilities of uses in individual flashlight models. Aside from that, still an excellent battery in all other aspects. Thank you for your review!!

This P1835K battery is a little puzzling. It does not show up on Keeppower’s website. It has a discharge curve essentially identical to the recently tested P1835J. They both match up well with the Sanyo NCR18650GA discharge curves.

The cell inside is supposed to be different.

Well, that is interesting. The P1835K weighs 1.7g more than the older P1835J and is 0.2mm shorter, but the differences in capacity you measured are negligible. After looking at some more discharge curves, I think the cell being used in the P1835K battery is the LG M36, and not the Sanyo GA.

A Google search does not turn up any vendors selling the P1835K battery. It appears that you have a rare pair of batteries in your possession. :wink: