Test/Review of Keeppower IMR26650 5200mAh (Black) 2014

[SIZE=+3]Keeppower IMR26650 5200mAh (Black) 2014[/SIZE]



Official specifications:

• Min Capacity: 5100mAh
• Typical Capacity: 5200mAh
• Type: Li-Mn
• Normal Voltage: 3.7V
• Quality Lithium Ion rechargeable cell
• Maximum Capacity and Reliability
• Ultra Discharge Current: 30A
• 4.2 volts max voltage and 3.6-3.7 volts nominal voltage
• Flat top: Yes
• Dimension: (D)26.50mm*(H)67.000mm
• Weight: Max. 95.0g

This is a high capacity unprotected 26650, that is supposed to deliver 30A. It does not do that.










There is a fairly good tracking between the cell, but they do not deliver 30A, they are more in the 10A to 15A range.















[SIZE=+3]Conclusion[/SIZE]

The cells works fine as unprotected high capacity cell, but they are not really super high current cells.



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

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
Compare to 26650 and other larger batteries

Thanks HKJ! You are really cranking out these reviews one after another non stop!

It's surprising to me that Keepower's IMR 4200mAh has better performance than their IMR 5200mAh.

THE_dAY said:

Thanks HKJ! You are really cranking out these reviews one after another non stop!

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On average I get a bit above two tests each week, when I have batteries in queue.
And my queue is rather long at the moment.

THE_dAY said:

It's surprising to me that Keepower's IMR 4200mAh has better performance than their IMR 5200mAh.

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Better performance depends on what you look at, the 5200mAh has more capacity and energy, but the 4200mAh keeps a higher voltage.

@HKJ Looks like you have a typo in the specs (20A vs. 30A). Is that supposed to be burst, or continuous? Probably burst, given the test results.

Gauss163 said:

@HKJ Looks like you have a typo in the specs (20A vs. 30A). Is that supposed to be burst, or continuous? Probably burst, given the test results.

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The specs are copied from Keeppowers website, but I can see they have changed the 20A to 30A now.

HKJ said:

Better performance depends on what you look at, the 5200mAh has more capacity and energy, but the 4200mAh keeps a higher voltage.

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Good point. Despite the fact that this is supposedly an 'IMR' cell, it is really more of a higher capacity version of the King Kong. In fact, voltages are VERY comparable at the same current levels.

hi henrik!

just a question. is this IMR26650-5200mah the same cell as the ICR26650-5200mah, BUT without the protection circuit?

i just looked at your comparator and the curves look almost identical except for the voltage drop caused by the protection circuit

Overclocker said:

just a question. is this IMR26650-5200mah the same cell as the ICR26650-5200mah, BUT without the protection circuit?

i just looked at your comparator and the curves look very similar except for the voltage drop caused by the protection circuit

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My guess is yes.

Thank you for your excellent review. HKJ! :thumbsup:

I have a question. At 0.2A discharge current, the relating voltage is about 4.2V. But at 15A current, the voltage is around 3.5V.
Are those voltage initial voltage? And why is this happening? This may be some kind of stupid question. :thinking:

candle lamp said:

I have a question. At 0.2A discharge current, the relating voltage is about 4.2V. But at 15A current, the voltage is around 3.5V.
Are those voltage initial voltage? And why is this happening? This may be some kind of stupid question. :thinking:

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What is initial voltage? Is it loaded or unloaded.

With a 15A draw I am placing a 0.24 ohm resistor (More or less) across the battery terminals. This makes a voltage divider with the internal resistance.
The math looks like this: 4.2/(0.24+0.07)*0.24 -> 3.25 volt

Because I am using a constant current load not a resistor, the correct math is: 4.2-0.07*15 -> 3.15 volt

The 0.07 ohm internal resistance has a large tolerance, it looks like my value is too high for a full cell.

Thanks again. HKJ!
It's right answer to the wrong question.

Overclocker said:

hi henrik!

just a question. is this IMR26650-5200mah the same cell as the ICR26650-5200mah, BUT without the protection circuit?

i just looked at your comparator and the curves look almost identical except for the voltage drop caused by the protection circuit

Click to expand...

I am puzzled that HKJ answered your question with a "yes". How can they be the identical cell if one has IMR chemistry and the other has ICR chemistry?

SubLGT said:

I am puzzled that HKJ answered your question with a "yes". How can they be the identical cell if one has IMR chemistry and the other has ICR chemistry?

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The correct usage for IMR is, of course, for a manganese based LiIon battery, but today it is often used for any high current battery.

I wish the ICR version would fit in an Olight R40 Seeker

I'm surprised KeepPower is so far off with this battery spec and naming. They have a good reputation i would hate to see them lose that. I hope their dealers will strongly voice their disappointment. Thanks for the test, I've been waiting for this one. I expexcted better from this company not only is the use of IMR naming low class, the battery does not even meet comparable specs or posted spec. Still an interesting cell for low to moderate drain, it sure shows the value of independent tests. Do they have a published data sheet for this cell?

HKJ said:

The correct usage for IMR is, of course, for a manganese based LiIon battery, but today it is often used for any high current battery.

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So IMR has become a marketing descriptor, instead of a technical descriptor. That is disappointing. What cell is likely to be underneath the KeepPower wrapper? A Panasonic?

SubLGT said:

So IMR has become a marketing descriptor, instead of a technical descriptor.

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Only for battery resellers, not for battery manufacturers.

SubLGT said:

That is disappointing.

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Yes, but not really that surprising.

SubLGT said:

What cell is likely to be underneath the KeepPower wrapper? A Panasonic?

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No, Panasonic does not make 26650. It is probably from a Chinese battery manufacturer.

HKJ said:

……………...No, Panasonic does not make 26650. ………………………….

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I did not know that. Is the Panasonic CGR26650B a fake, or genuine?

SubLGT said:

I did not know that. Is the Panasonic CGR26650B a fake, or genuine?

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I do not know that, but I have not seen any data on 26650 from Panasonic.

I just checked for a 26650 battery on Panasonic's global battery website, and found no 26650 batteries. So the CGR26650B is probably a fake.