Test/review of LG 21700 M50 5000mAh (Grey)

HKJ · 2019-05-14T15:25:08.000Z

LG 21700 M50 5000mAh (Grey)

Official specifications:

Nominal Energy: 18.20Wh (5013mAh at nominal voltage)
Minimum Energy: 17.60Wh (4849mAh at nominal voltage)
Nominal voltage: 3.63V
Nominal shipping SOC: 30%
Standard charge current: 1455mA (0.3C)
Charge cut-off: 4.2V 50mA
Standard discharge: 907mA (0.2C)
Discharge cut-off: 2.50V
Cycle life: 500 cycles to 80% of Wh min.
Maximum pulse discharge power: 80W for 10sec
Maximum discharge current: 7275mA (1.5C) in temperature range 5°C ~ 60°C

This is a high capacity 21700 cell with about 5000mAh, the cell is not for high current.

The two cells are well matched.

The battery gets fairly warm at 15A
It looks like I have a problem with my temperature sensor.

The defect temperature sensor made the B battery fail permanently, it got too hot.

Conclusion

This is a one of the best high capacity batteries.

Notes and links

The batteries was supplied by batteridoktorn.se 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

Agro · 2019-05-14T15:36:30.000Z

Actually the highest capacity 21700 up to 10A discharge…which covers most cases of sustained flashlight use.
BTW your table of all cells misses capacity measurements of this at 0.2A.

Thanks HKJ!

Lux-Perpetua · 2019-05-14T15:39:16.000Z

Maybe Molicel's M50A will match or surpass the LG M50. But Molicel is probably cheating as the M50A's diameter is 21.7mm, i.e. larger than or at least as large as the inner diameter of many battery tubes of 21700 lights. ;-)

HKJ · 2019-05-14T15:48:56.000Z

Agro:

BTW your table of all cells misses capacity measurements of this at 0.2A.

I know, but something went wrong with one of the cells and i do not have a full curve. The table building software excludes data if the two cells in a test do not match.

Superstocker · 2019-05-14T17:35:15.000Z

Thanks HKJ!

wolfdog1226 · 2019-05-14T17:56:18.000Z

Thanks HKJ.

The voltage curves are basically identical w/ the Samsung 50E

RelakS · 2019-05-15T06:05:15.000Z

HKJ, what software do you use to draw these diagrams? I haven’t found it on your website even if it is mentioned.

HKJ · 2019-05-15T06:22:42.000Z

RelakS:

HKJ, what software do you use to draw these diagrams? I haven’t found it on your website even if it is mentioned.

My own software, it used a library called JFreeChart: http://www.jfree.org/jfreechart/
All my tests are saved as CSV files and then I use the above to draw the charts from the CSV files.

KevinZA1988 · 2019-05-15T06:34:36.000Z

This looks like the cell I found when I took the wrapping off my Rofis 21700 protected cell. Hmmmmmm….

RelakS · 2019-05-15T13:12:29.000Z

HKJ:

RelakS:

HKJ, what software do you use to draw these diagrams? I haven’t found it on your website even if it is mentioned.

My own software, it used a library called JFreeChart: http://www.jfree.org/jfreechart/
All my tests are saved as CSV files and then I use the above to draw the charts from the CSV files.

Thank you!
The CSV part is OK, but Excel/LibreOffice does not support more than two Y axis…

shadockan · 2019-05-19T06:28:41.000Z

Lux-Perpetua:

Maybe Molicel’s M50A will match or surpass the LG M50. But Molicel is probably cheating as the M50A’s diameter is 21.7mm, i.e. larger than or at least as large as the inner diameter of many battery tubes of 21700 lights.

The Moli M50A is a 20A battery.
Moli will have less voltage drop … so it will later reach the cut-off point
It is not correct to compare different batteries ……

EasyB · 2020-04-18T13:07:52.000Z

Just bought a couple of these at imrbatteries for $3.99 each. Seems like a great deal; hopefully they are not really old and degraded.

Edit: just received these and they are actually M50T, just FYI.

radellaf · 2022-02-28T20:22:04.000Z

Got a couple of these out of a Ravpower 20W PD power bank that bit the dust. $8 worth of batteries for a bit over $20. It’s something.

Looks like the performance falls off pretty fast over 5 amps. My S21A and S12 Convoy are 6 amp max drivers so they should be good in those, and the slight left over spot weld nubbins shouldn’t bother the springs. I’ll leave them out of the Emisar (amps) or ZL SC700 (pogo pin contacts).