Test/Review of Xtar 18650 3100 mAh (Black)

Xtar 18650 3100 mAh (Black)

Official specifications:

  • XTAR 18650 3100mAh Protection Li-ion battery
  • Voltage::3.7V
  • Net Weight: 46g
  • Size: ø18.4±0.1mm x 68.5±0.5mm
  • Battery Capacity:3100mAh
  • Cell: Panasoinc lithium cell inside

The cell used can be discharged down to 2.5 volt, in my test I only discharges to 2.8 volt, i.e. I do not measure the full capacity. But then, not all lights will be able to use the full capacity.


This battery uses a good cell, this secures many things:

  • The batteries does match in capacity, i.e. they can be used in series.
  • The battery is very safe.
  • The battery has the specified capacity (But only when tested at the specified conditions).

All in all a very good battery.

Notes and links

The batteries was supplied by Xtar 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

I notice from the Panasonic data sheet for the NCR18650A cell that temperature has a marked effect on performance, producing a noticeable increase in capacity the higher the temperature.

This is common for all LiIon batteries. For some batteries it can be seen on the discharge curves: the capacity at high discharge current is the same or slightly higher than at lower current.

Thanks, HKJ!

I come to know after having so much of analysis that, the increase temperature result in lowing the battery performances.

It is probably related to how much it heats up.

With this battery you can see that the 3A trace has same capacity as the 2A trace and the 5A trace has more capacity than both 2A and 3A trace.

I Guess there will be an optimum temperature around 25 degrees. I notice at freezing and below the run time is very short in a flashlight.

No, it is much higher. The Panasonic NCR18650A datasheet has curves up to 60 degrees and the 60 degrees has most capacity.

The lifetime of the battery will be reduced when working at these high temperatures.

Hello mattjohn. Welcome to BLF!