Test/Review of Keeppower IMR26650 3500mAh (Black) 2014

Keeppower IMR26650 3500mAh (Black) 2014



Official specifications:

  • Brand Name: KeepPower
  • Type: Li-Ion
  • KeepPower IMR 26650 3.6V/3.7V 3500mAh High Drain Li-ion Rechargeable Battery
  • Min Capacity: 3400mAh
  • Typical Capacity: 3500mAh
  • Normal Voltage: 3.7V
  • Quality Lithium Ion rechargeable cell
  • Maximum Capacity and Reliability
  • Maximum Constant Discharge Current: 20A
  • 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. 93.0g





This battery is rated as a high current type.











The two batteries has different capacity and being unprotected this makes them very bad for usage in series.
The batteries can handle up to 20A, but does heat up.















Conclusion

These batteries are acceptable for single cell use, but due to the difference in capacity not for usage in series.
The high current performance is acceptable, but it is possible to find 26650 with lower capacity, but considerable better high current capability.



Notes and links

The battery 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

Once again, thanks for the great review. These are super valuable for us when deciding what batteries to buy.

These looks like great batteries at 5A for use in single cell lights. ^^

Anyone know if a good cheap source with international shipping?

Thanks for the tests. Its to bad there are such inconsistencies with these cells that you should not use them in series. It makes you wonder what might be hiding under the wrappers.

There is no protective circuit.

Probably because someone reused the label design from another 26650 cell type.

This cell, like all IMR cells, is without any circuit or IC's.

The label does not seem reused at all.

The cells have printed:

"20A Ultra High Drain Li-ion Recharable Battery"

"IMR26650 3.7V 3500mAh"

"IC made in Japan"

All the information is specific to the cell sent, which shows the label was done specifically for those cells. "IC made in Japan" is a slip-up? that is another thing.

I do not know how Keeppower works, but if I have to make a new product label I will usual load an old design, edit the required fields and save it as the new product label. With that type of work flow it is possible to miss a field.

Remains an incorrect data, even if mostly seems like it's an oversight, a slip-up, which is not the first time with KP as far as we now.

It is and Keeppower will fix it according to the PM they send me.

It would be easier to take you guys seriously if you were upset about something that matters (mismatched capacity between cells) instead of a misprint on the damn label.

To be fair it is a problem, it shouldn’t imply there is an IC on there as that could lead to improper use. It does deserve to be pointed out, but I trust Keeppower will fix the issue and move on, whilst continuing to supply us with top of the line cells at a very good price.

THIS!

Is the mismatched capacity common among Minke cells?
It seems to me that Keepower is only a brand in that it adds its own protection circuits to another brands cells and relabels them. If IMRs have no protection circuits added, then they are just rewrapping Minkes. What’s the point?

As always to promote the brand name and get freedom from a specific supplier. As long as there is no specification saying that a specific cell is used, it is possible to swap supplier.

One good example is Duracell that is using Duracell branded batteries with Eneloop cells inside, at least sometimes.

Thanks again HKJ for your hard work providing us with this information.

I do not agree with that. First, they did not post that they were upset did they? What is the point of an open forum about these products if they are told they should shut up? I think your post is out of line and offensive, and that you might want to consider editing your bad language.

Gee golly, are we in a mormon forum? Can't be because I've heard worse on mormon pulpits, and there was even a high ranking mormon leader that used foul language in front of congregations. The label is sloppy, but I wouldn't care much if the vendor did a good job of providing the specs, although I'd need to record those specs somewhere, and I'm awful about keeping specs of all my batteries. This thread is another example of why I think vendors should have KP retain the original shrink wrap under the KP shrink wrap.

I agree with your sentiments. In fact, I’m just using a previous post that was made in this forum on March 20 2013 by a user calle ‘Bones’. He used the same word, I thought nothing of it, but a user by the name of ‘Brad’ called him out on it. So Bones got a note from Admin asking him to edit the bad language out of his post, which he did, and everyone was happy. Being a new citizen of the forum at the time, I kept my opinions to myself, but now I figure I’ve been around long enough I have earned the right to comment on such matters. The language in fact does not bother me personally, but what I do not appreciate is the fact that posters like Hikelite may be discouraged from expressing their valid opinions. Ironically for the first time I saw that Cateyes did make some valid points in his diatribes, it’s just that they got so lost in the verbose jibberish I had missed them before.

Thanks HKJ for another fantastic review. Do you have the numerical capacities of these batteries? The difference in capacity is hard to tell from the charts. These batteries will have different resistance values also?

Something like this: