Test/Review of Keeppower 16650 2500mAh (Black) 2015

[size=+3]Keeppower 16650 2500mAh (Black) 2015[/size]



Official specifications:

• Capacity min.: 2400mAh
• Capacity typ.: 2500mAh
• Nominal voltage: 3.70V
• Charge voltage: 4.35+/-0.05V
• Standard discharge cut-off voltage: 3.00V
• Standard charge current: 1000mA
• Charge termination current: 50mA
• Standard discharge current: 2400mA
• Max. continuous discharge current: 6A

This is a slimline version of the xx650 battery, it can usual replace two CR123 cells. It has a lower voltage, but more capacity.











The discharge curves looks very good, but the capacity is rather low. The low capacity was expected, the problem is the protection circuit, it terminates before the battery is full!













Look at the voltage drop when charging terminates, it is way to large because of the protection circuit.



Charging with 4.30 volt



Lets try a slightly lower charge voltage.



The batteries has more capacity at this voltage and the discharge curves looks good.













No big drop when charging terminates, this time the protection did not trigger.



Charging with 4.20 volt



What about using a normal LiIon charger?



It is about 200mAh less than 4.30V charging.















[size=+3]Conclusion[/size]

It would have been nice with a protection circuit for 4.35V, but even with the capacity loss the battery is a good and a very good substitute for CR123 in lights that can handle the lower 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
Compare to 18650 and other batteries

Thank you for this review! Interesting how they have more capacity at 4.3V than 4.35V.

Bright_Light said:

Thank you for this review! Interesting how they have more capacity at 4.3V than 4.35V.

Click to expand...

That is because the protection prevents a full charge at 4.35 volt.

This cell wasn't even on my radar, but the capacity makes me do a double take. I would expect it to have similar capacity to 2x16340, but it has... at least twice as much capacity as 2x16340. How is this possible? How come 16340 rechargeable cell capacity hasn't come close to 1000mAh yet, but still lingers at half that? This 16650 nearly has the capacity of 2 primary CR123A cells.

chillinn said:

How come 16340 rechargeable cell capacity hasn't come close to 1000mAh yet, but still lingers at half that?

Click to expand...

The big factories with the advanced technology do not make 16340* and the smaller factories that makes 16340 do not have the technology to make the high capacity.
*Even if they have one, they do not use the money to update the cell.

I've been using the 2000mAh Keeppower 16650 for years in my light not bored for 18mm.
Very satisfied, a bit more runtime than CR123.

Lots of places saying that this is discontinued. I hope not! Maybe gearing up for a replacement?

chillinn said:

This cell wasn't even on my radar, but the capacity makes me do a double take. I would expect it to have similar capacity to 2x16340, but it has... at least twice as much capacity as 2x16340. How is this possible? How come 16340 rechargeable cell capacity hasn't come close to 1000mAh yet, but still lingers at half that? This 16650 nearly has the capacity of 2 primary CR123A cells.

Click to expand...

He'll, look at 17650. They are a bigger battery " obviously" an have no where near the capacity of a 16650. Biggest reason is research And development. People want this size more then the 17650 so they haven't bothered to work on them.