Test/Review of Keeppower 26650 4000mAh (Black)

[size=+3]Keeppower 26650 4000mAh (Black)[/size]



Official specifications:

• 26650 4000mAh Protected Rechargeable Battery
• Min Capacity: 4000mAh
• Typical Capacity: 4100mAh
• Normal Voltage: 3.7V
• Standard charge current 2000mA
• In Built Safety Circuitry
• Protection Circuit (Against overcharge, over discharge, over current and short-circuit.)
• 4.2 volts max voltage and 3.7 volts nominal voltage

The battery does easily meet the specified capacity.
Note: The internal resistance is calculated from 6 to 10 ampere.











Lots of capacity, but the batteries has difference capacity especially at high loads.











The protection trips at a very high value, as can be seen the output of the batteries has started to go down, before the protection trips.





[size=+3]Conclusion[/size]

This is the first keeppower battery I have seen, where I am disappointed with it, the performance is good, but I do not like the difference between the cells and the very high trip point of the over current protection.



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

Keeppower is a OEM manufacturer, i.e. many of the batteries they produce is sold with other names on them.

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

One hint: it is basically impossible to tell apart to colors in the discharge graph if the legend is only 1 pixel wide.

Whats up with the 2 strongest current drops? Logic suggests that these are the highest discharge currents, but non of the high current in the legend have the salmon color the lowest curve has.

IMSabbel said:

Whats up with the 2 strongest current drops? Logic suggests that these are the highest discharge currents, but non of the high current in the legend have the salmon color the lowest curve has.

Click to expand...

Salmon is 10A discharge for the "A" cell.

IMSabbel said:

One hint: it is basically impossible to tell apart to colors in the discharge graph if the legend is only 1 pixel wide.

Whats up with the 2 strongest current drops? Logic suggests that these are the highest discharge currents, but non of the high current in the legend have the salmon color the lowest curve has.

Click to expand...

The legend is part of the charting package I uses, I do not know if it is possible to change it.

Generally it is not a huge problem to relate the curves to the legend, because they nearly always are in sequence.

Shadowww said:

Salmon is 10A discharge for the "A" cell.

Click to expand...

Ah, Ok. But this makes it a HUGE difference between both cells. I mean, factor 2 difference in capacity between 2 cells of the same type with just 2.5C discharge current?

Thanks for the comprehensive review HKJ.

Where can I pick these up at? I googled them but found only Lipos in 26650 size.

vestureofblood said:

Where can I pick these up at? I googled them but found only Lipos in 26650 size.

Click to expand...

With Keeppower it is difficult to say where you can get the batteries. Anybody can order a pile of batteries from them, either with the Keeppower name or with another name. The problem is you have to order a many batteries, i.e. it will usual be dealers that orders from them.

It is not that difficult to find 26650 batteries, the problem is finding some in top quality.

Excellent review as always. HKJ! :thumbsup:

Many thanks for your time & effort.

Great review, I didn't even know these were available, I'm very happy with my Keeppower 3100mAh cells and I'll be ordering these to replace my unprotected no name cells.

Norm