The brand name Samsung Li-ON cells have very poor life-cycle performance.

Please see the information from the official Samsung datasheet. This information shows that the life span for the ICR 18650-26A model is only 300 cycles!  After 300 cycles the capacity will drop to 70%.  What a contrast with the LiFePO4 cells that have 2000, 3000, 4000 or even 8000 full cycles.

We suggest avoiding the usage of such Li-ON cells for any serious applications.

Please think about this: if the TOP manufacturer Samsung gives „confidential“ information with such a low cycle life span, how much lower will be the life span of the identical cells produced by some no-name Chinese manufacturers?  Well we even do not wish to try to guess what the reality may be.