Test/review of Shockli 21700 4000mAh (Black) 2018

HKJ · 2018-05-28T14:15:26.000Z

Shockli 21700 4000mAh (Black) 2018

Official specifications:

Type of Battery: Shockli 21700 4000mah IMR battery 20A
Size(mm): 21.7±0.2mm(Diameter) x 70.9±0.2 mm(Length)
Weight(g): 70±2g
Nominal Voltage: 3.7V
Nominal Capacity: 4000mah (0.2C Discharge)
Discharge Cut-off voltage: 2.75 V
Standard Charge: 0.3 A~2A (Recommend 0.5 A~1.5A) /4.2V±0.05V
Maximum charge current: 2A
Continuous Discharge Current: 20A
MAX Discharge Current: 30A
Initial Impedance: < 20 mOhm
Cycle Life: 500times: discharging capacity to 80%
Operating environment: Charging, 0°C ~ 45°C, Discharging, –10°C ~ 60°C

This is one of the newer cell sizes with more capacity and high current.

This is very nice discharge curves with good match and nearly constant capacity, even at high current. I had to stop the 20A and 30A discharge due to heat.

Conclusion

These cells can deliver a lot of current and has more capacity than the older 18650 size, the cells has good discharge curves.

Notes and links

The battery was supplied by shockli.com 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

Splott-Light · 2018-05-29T12:19:17.000Z

HKJ,
Thanks for your review.
Much appreciated.
Loving the characteristics of these newer sized batteries.
Look forward to more lights being produced to use them.
Cheers,
S-L

P.S. Looks like you may need to upgrade your discharging rig!
Don’t forget to ask us all for funds if you do.
Don’t ask, don’t get!

Satan · 2018-05-29T12:38:31.000Z

Look very alike LiitoKala 21700 4000mAh may be the same cell.

HKJ · 2018-05-29T16:15:29.000Z

Splott-Light:

P.S. Looks like you may need to upgrade your discharging rig!

I can discharge with above 100A, the problem is my battery holder, it melts.
I do not with to return to thick copper rods, I like the better precision from a 4 terminal rig.

Splott-Light:

Don’t forget to ask us all for funds if you do.
Don’t ask, don’t get!

I have published a paypal address (info@lygte-info.dk), if you want to help me (I am often buying stuff to test and sometimes also new equipment).

Pete7874 · 2018-05-29T16:29:56.000Z

HKJ, thanks for the review.

Is it possible to increase the scale on the X axis in your comparator tool? Part of the curve is getting cut off. Thanks!

HKJ · 2018-05-29T16:32:23.000Z

Pete7874:

HKJ, thanks for the review.

Is it possible to increase the scale on the X axis in your comparator tool? Part of the curve is getting cut off. Thanks!

Use the 26650 comparator instead: Battery test-review 26650 comparator
20700 & 21700 is also added there.

Pete7874 · 2018-05-29T17:04:00.000Z

Thanks!

Agro · 2018-05-29T19:00:15.000Z

As we’re talking comparators… recently I wanted to compare 18350 and 26650 batteries. None of the comparators has them both

HKJ · 2018-05-29T19:39:05.000Z

Agro:

As we’re talking comparators… recently I wanted to compare 18350 and 26650 batteries. None of the comparators has them both

They are too far from each other, it would not be meaningful to put them in the same comparator.

Agro · 2018-05-30T08:23:09.000Z

HKJ:

Agro:

As we’re talking comparators… recently I wanted to compare 18350 and 26650 batteries. None of the comparators has them both

They are too far from each other, it would not be meaningful to put them in the same comparator.

If I have a 26350 light what is the best high-current battery for it?

Aspire 18350.

No, I don’t think they are far from each other. They are one-way compatible and have competitive performance.

HKJ · 2018-05-30T08:36:16.000Z

Agro:

HKJ:

Agro:

As we’re talking comparators… recently I wanted to compare 18350 and 26650 batteries. None of the comparators has them both

They are too far from each other, it would not be meaningful to put them in the same comparator.

If I have a 26350 light what is the best high-current battery for it?

Aspire 18350.

No, I don’t think they are far from each other. They are one-way compatible and have competitive performance.

You asked about a 26650 battery compare to a 18350 battery, that is a 4000-5000mAh compared to a 1000mAh battery, and they are very different in size.
Comparing 26350/18350 may be more interesting, but I have only tested one 26350.

Agro · 2018-05-30T08:36:57.000Z

HKJ:

Agro:

HKJ:

Agro:

As we’re talking comparators… recently I wanted to compare 18350 and 26650 batteries. None of the comparators has them both

They are too far from each other, it would not be meaningful to put them in the same comparator.

If I have a 26350 light what is the best high-current battery for it?

Aspire 18350.

No, I don’t think they are far from each other. They are one-way compatible and have competitive performance.

You asked about a 26650 battery compare to a 18350 battery, that is a 4000-5000mAh compared to a 1000mAh battery, and they are very different in size.
Comparing 26350/18350 may be more interesting, but I have only tested one 26350.

Typo. I meant 26350.