Test/Review of Keeppower 18650 3200mAh (Black) 2014

HKJ

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[size=+3]Keeppower 18650 3200mAh (Black) 2014[/size]

DSC_4824.jpg


Official specifications:
  • Min Capacity: 3100mAh
  • Typical Capacity: 3200mAh
  • Normal Voltage: 3.7V
  • Quality Lithium Ion rechargeable cell made in Korea
  • Maximum capacity and reliability
  • Size: L:69.00mm*D:18.50mm
  • Cell made in Korea
  • High Discharge Rate (Max 2C)
  • Protection Circuit (Against overcharge, over discharge, over current and short-circuit.)
  • 4.2 volts max voltage and 3.6-3.7 volts nominal voltage
  • Over 500 times of charge and discharge cycle life.


Keeppower%2018650%203200mAh%20(Black)%204.35V%202014-info.png


This is the highest capacity cell with 4.35 volt at the current time, but due to the protection the mAh is to low.

DSC_4823.jpg


DSC_4825.jpg
DSC_4826.jpg


DSC_4827.jpg

DSC_4828.jpg



Keeppower%2018650%203200mAh%20(Black)%204.35V%202014-Capacity.png


The discharge curves does not looke very nice, but that is not due to any problem with the cell, it is because the protection has intefered with the charging.
It can also be seen that the protection trips after some time at 7A.

Keeppower%2018650%203200mAh%20(Black)%204.35V%202014-CapacityTimeHours.png


Keeppower%2018650%203200mAh%20(Black)%204.35V%202014-CapacityTime.png


Keeppower%2018650%203200mAh%20(Black)%204.35V%202014-Energy.png


Keeppower%2018650%203200mAh%20(Black)%204.35V%202014-PowerLoadTime.png


Keeppower%2018650%203200mAh%20(Black)%204.35V%202014-TripCurrent.png


Keeppower%2018650%203200mAh%20(Black)%204.35V%202014-Charge.png


Here it is obvious that one cell stops charging, before the other and probably neither of them is fully charged (The voltage drop when the charge current stops looks to large).



[size=+2]Test with 4.3 volt charging[/size]

Reducing the charge voltage slightly gets around the problem with the proction.

Keeppower%2018650%203200mAh%20(Black)%204.30V%202014-info.png


Keeppower%2018650%203200mAh%20(Black)%204.30V%202014-Capacity.png


The difference between 4.3 and 4.35 volt charging is minimal. This time the curves look fine.

Keeppower%2018650%203200mAh%20(Black)%204.30V%202014-CapacityTimeHours.png


Keeppower%2018650%203200mAh%20(Black)%204.30V%202014-CapacityTime.png


Keeppower%2018650%203200mAh%20(Black)%204.30V%202014-Energy.png


Keeppower%2018650%203200mAh%20(Black)%204.30V%202014-PowerLoadTime.png


Keeppower%2018650%203200mAh%20(Black)%204.30V%202014-TripCurrent.png


Keeppower%2018650%203200mAh%20(Black)%204.30V%202014-Charge.png


Both cells is fully charged here.



[size=+2]Test with 4.2 volt charging[/size]

Keeppower%2018650%203200mAh%20(Black)%202014-info.png


Using a normal 4.2 volt LiIon charger does cost capacity, about 250mAh compared to 4.3 volt.

Keeppower%2018650%203200mAh%20(Black)%202014-Capacity.png


Keeppower%2018650%203200mAh%20(Black)%202014-CapacityTimeHours.png


Keeppower%2018650%203200mAh%20(Black)%202014-CapacityTime.png


Keeppower%2018650%203200mAh%20(Black)%202014-Energy.png


Keeppower%2018650%203200mAh%20(Black)%202014-PowerLoadTime.png


Keeppower%2018650%203200mAh%20(Black)%202014-TripCurrent.png


Keeppower%2018650%203200mAh%20(Black)%202014-Charge.png




[size=+3]Conclusion[/size]

Being based on LG cells, it is good batteries, but with the slightly low protection voltage they do not give the full benefit of the higher voltage.



[size=+3]Notes and links[/size]

The batteries was supplied by Keeppower 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
 

ChrisGarrett

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Miami, Florida
Maybe take them apart, remove the PCB and retest them?

Thanks though, but it looks like Keeppower has screwed the pooch on this one.

Chris
 

candle lamp

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Thanks for your excellent test review again. HKJ! :thumbsup:

It seems the capacity even with 4.35V charge is not so high than expected.

Dose the protection circuit have a great effect on the capacity?
 

HKJ

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Messages
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Location
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It seems the capacity even with 4.35V charge is not so high than expected.

Does the protection circuit have a great effect on the capacity?

The difference on the two cells is up to 250mAh, I would expect 50 to 150mAh more than the best cell, if the protection has not interfered with the charging.
In the previous generation the difference between 4.3 and 4.35 volt was 110mAh.
 

HKJ

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hi henrik, what can you say about this versus the D1? seems like the D1 is still "better"

Depends, you cannot compare the 4.35 volt values, due to the low protection threshold. Try comparing the 4.30 volt or 4.20 volt values instead. This cell has more capacity.
You cannot really compare how they handle current draw, because this cell is protected, the D1 is not, but my guess is that the D1 is better.
 

vicv

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Mar 22, 2013
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Crossing fingers waiting for the results from the bare cell test. I was about to buy some d1's then noticed this. Now I can't wait till this higher voltage technology gets to high drain cells and they'll be amazing.
 
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