Test/review of Samsung INR18650-25S 2500mAh (Purple)

Batteries and Chargers Rechargeable Batteries
1

Samsung INR18650-25S 2500mAh (Purple)







Official specifications:

  • Minimum capacity: 2450mAh

  • Rated capacity: 2400mAh

  • Nominal voltage: 3.6V

  • Standard charge: CCCV 1.25A, 4.2V, 125mAh cut-off

  • Rapid charge: CCCV 4A, 4.2V, 100mAh cut-off

  • Maximum continuous discharge: 25A, 35A with 80°C cut-off

  • Discharge cut-off: 2.5V

  • Cycle life: 250 cycles to 60% with 4A charge and 25A discharge.

  • Operating temperature: Charge: 0°C ~ 50°C, discharge: –20°C ~ 80°C

  • Storage temperature: 1 month: 0°C ~ 60°C, 3 months: 0°C ~ 45°C, 1.5year 0°C ~ 25°C



This is a fairly new high current cell from Samsung.










The discharge curves tracks just about perfect and the cells can handle 30A





















Conclusion

This cell is for high current applications, that is in the 10A to 30A range, where it looks very good.



Notes and links

The batteries was supplied by Apexium 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
Compare to 18650 and other batteries
2

Holds voltage a bit better than VTC5A, but capacity is not there. OTOH it’s nearly exactly as powerful as 24S, but has higher capacity. Good!

3

I can assure you that the capacity is a minimum of 2450mAh, but it may be necessary to discharge them up to 2.5v, and it really, not 2.8v!!! I have 4 Samsung INR18650-25S cells of the same batch as HKJ (2H44) and I discharged them with 0.5A, from 4.20v (real) to 2.50v (real) (just put an amp cut-off setting to 0.01A for that), I got the following results:

#01: 2553mAh
#02: 2525mAh
#03: 2545mAh
#04: 2532mAh

So you have to discharge up to 2.50volts, otherwise you will not have the 2500mAh, that’s where it is that you got a mediocre grade.

4

FYI, mine are Rank A2, so not the best is to say.

5

@Hydraxx, no worry here. 2.8V is used here since most devices won’t draw the cell down to 2,5V, so using 2,8V is more accurate for capacity measurement

As long as the difference in capacity is not higher than 10%, I have no problem believing the cell is a step-up from the VTC5A in terms of internal resistance.

6

I meant that VTC5A offers higher capacity, not that these don’t meet their specs (though I do believe that rating capacity and durability in different discharge cycles is a scam that everyone does).

7

I agree that most devices are not capable or are not tuned to use Lithium-Ion cells up to 2.50v, that’s quite true. But I do not agree, on the fact that you say that unloaded up to 2.80v is an accurate measure of cell capacity, Lithium-Ion cells are created and designed initially to be discharged up to Voltage Cutoff defined by the manufacturers and it is not the fault of the marks of cells, if the manufacturers of devices using them do not know the exploited correctly, all is always question of adjustments, and of course to know made adjustments . So for me, I mean for me, performing a capacity test of a cell correctly, it is discharged properly, through (2.50v). And of course, there is always a difference between theory and practice.

8

Looks this is the next generation of 20Q and 20R.
Samsung did a good job on this one.
Can’t wait to see these in power tools.

@HydrAxx - Do we consider cheating if manufacturer states the total capacity considering a discharge of under 3.3V ? I think we mostly should, if this is the case … and this is because any tools were designed to consider this limit. So it’s not fair to rate a cell 3400 instead of 3100mAh just because it can go under 3.3V while sustaining the specified current. At least this causes additional wear.