Test/Review of LiitoKala INR 26650 5000mAh cells.

[CuriousOne]

These cells entered our life with a bit of mysterious fleur - Price
is ridiculously low, the "brand" is widely known in the narrow field
of flashaholics and battery=dreamers, due to it's "analyzing"
chargers (but no word about batteries on their website). More haze is
added by a bunch of Opus 3100 "analyzing" charger users, which are
showing photos of chargers, measuring these cells as 5500mAh. As I'm
working on certain project, where high current is needed, but usage
of LiPo's is not welcomed, these cells appeared to be the right
choice for me, so I ordered 3 of them. Why 3? because my project
initially was using 3S lipo battery. Ordered them at gearbest, using
the following links for 1 cell and 2 cell pack:
http://www.gearbest.com/batteries/pp_360840.html
http://www.gearbest.com/batteries/pp_360841.html delivery to
NJ, US took about 1 month. So finally they arrived, I've unpacked
them, and found out that these are different cells! See it by
yourself:

The single packed battery is a bit darker, is marked as INR26650-50A,
while 2 pack is marked as 26650-50B and are bit ligther, and with
more deeply located positive pin. The "brand" Liitokala, is affixed
to cells, by means of transparent tape:

For testing purposes, I will call 2 pack cells "A" and "B", and will
call single pack cell as "C" cell.
As online shops love to show inflated specs for the batteries, I
decided to do a search, and find real manufacturer of these cells, so
I can have more precise information about cells available. By using
help from a skilled Chinese friend, I was able to determine (with
high probability, around 99%) makers of these cells. In case of "C"
cell, this is Chinese company, called "PLB":
http://www.plb.com.cn/Products/rlx5000mas.html In case of "A" and
"B" cells, maker is "Hengji Battery", website and battery specs were
not found. Assuming that cells should be mostly similar, I will use
specs for battery "C", as a reference for others too. So, specs are
as follows:

Capacity: 5000mAh
Charge current: 2.5A
Charge cut-off current: 100mA
Nominal discharge: 5A, with 2.75V cutoff
Max. discharge current: 5C (25A)
So I will be using above data for testing (except cut-off voltage, as
practice showed, belov 3V, discharge to 2.75V delivered maybe 30-
40mAh, so I decided not to force cells to that extent).
The results are as follows:
Capacity, mAh:
Cell A: 4922
Cell B: 4900
Cell C: 5002
Energy, Wh
Cell A: 16.88
Cell B: 16.81
Cell C: 17.06
Internal resistance
Cell A: 22 milliohms
Cell B: 22 milliohms
Cell C: 23 milliohms
Weight
Cell A: 91.5 grams
Cell B: 91.2 grams
Cell C: 93.2 grams
Dimensions:
Cell A & B: 65.15mm length, 26.52mm diameter, Positive pin is about
0.5mm below shrink wrap.
Cell C: 64.82mm length, 26.62mm diameter, Positive pin is at level of shrink wrap.

By looking at the above chart, the following conclusions can be made:
Cells "A" and "B" have almost similar curves, this means, they can be
used in series (temperature graphs are different, but explanation
will follow)
Cell "C" has different discharge curve, different temperature curve,
so it is appears to be really made at different factory.
For comparison, I've added curves in magenta color, from the previous test of Avatar INR 26650 cells, full review is here: http://www.candlepowerforums.com/vb...NR-26650-4200mAh-cell-with-worldwide-delivery

Conclusion:
Great cells, but if you're lucky to get batteries from same supplier. Even being different, they are still quite usable, even in series, but you will need spacer anyways. Also, above mentioned "Avatars" have higher charge current, 4.5A vs 2.5A, in case of these cells, this means approx two times lower charge time, but I haven't seen any 26650 charger, which can deliver 4.5A. If you have hobby charger, than of course it will work just fine.
And about difference in temperature curves between "A" and "B" cell. I started test with "A" cell, positioned free in space, vertically. For "B" cell, I've placed it horisontally, and as can you see, temperature graphs changed a bit. So, tests with "C" cell, were also concluded in the horisontal position of the cell, free hanging in the air.

All batteries reviewed, were bought using my own money, and was not provided for review by anyone.

Thanks for reading, and have a nice day!

 

[mjgsxr]

Thanks for the test. Nice to get some real data on these 26650. I bought some of ailexpress and received the dark wrapped batteries. So far I'm happy with them in my convoy L6

 

[CuriousOne]

Thanks!

These cells are also available in 3rd variation, still made by Hengji Battery, but marked as 26650-50A.

 

[SG Hall]

Thanks CuriousOne, great review. These are budget priced cells with great performance by the looks.

 

[CuriousOne]

Yes, I will put them to great stress shortly, and maybe in month, I will have enough information about their long term performance.

 

[CuriousOne]

Right now I'm testing very interesting charger - it has 3 slots, can charge 3 18650 cells with 2A current each, by using USB connection (Quallcomm QC 2.0 compatible, ac adapter included), can charge NimH same time, and has power bank function, stay tuned for review

 

[mjgsxr]

I have run 4 of these in series in a 100w mag, pulling over 10amps.
So far so good.

I find it strange that there should be 3 versions in such a short space of time . Are they making improvements?

 

[CuriousOne]

As Liitokala itself does not produce any cells, I guess, they just buy from the factory, which gives the best price, and affix their label. But in overall, situation is improving - if anyone would told me year ago, that there is pure Chinese cell, which delivers 5Ah at 10A - I would laugh a lot.

 

[CuriousOne]

As promised, started stress testing of these batteries. 60A current is drawn for 2 seconds, then 10 second pause and again 2 second discharge (20 cycles total). As this was first test, no measurements were made, I was just checking, whenever cells will go boom, emit noises, melt, etc. Nothing bad happened. So shortly, I will run more detailed test in that mode, and post back results.

 

[Capolini]

Thanks for testing these.

It is all about preference,,,,,,One never knows what/when they are getting when they buy overseas.

My reason for buying within the USA,,,,,,,,,I will stick w/ my Vappower IMR 26650 4200mAh whose overall performance was more consistent from cell to cell.

 

[Impossible lumens]

Thanks for the review and information. I guess if you don't need to drive the Amps too hard, these Liitokala 5,000s seem to be the best value around. Time will test the validity of my statement though.

 

[stephenk]

Thanks for the review. The fact that these are made by two different companies is important to note when using in series. Interestingly, it was commonly thought that these were made by BAK, which doesn't seem to be the case.

 

[CuriousOne]

My device has to recharge 5600 uf capacitor to 450 volts in 2 seconds or less, so these batteries will have a tough life anyways