Test/review of Sanyo NCR20700B 4000mAh (Red)

Batteries and Chargers Rechargeable Batteries
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Sanyo NCR20700B 4000mAh (Red)







Official specifications:

  • Rated capacity: 4000mAH

  • Minimum capacity: 4050mAh

  • Typical capacity: 4250mAh

  • Nominal voltage: 3.6V

  • Discharge current: 15A

  • Charging voltage: 4.20V

  • Standard charging current: 2000mA

  • Temperature: Charge: 10°C ~ 45°C, discharge: –20°C ~ 60°C, storage –20°C ~ 50°C




This is a new battery size that is slightly larger than the common 18650 cell.












The discharge curves for the two cells track nicely.







One of the cells got really hot during the 20A discharge. With the other I probably forgot to place the thermo sensor on the battery.















Conclusion

This size has more capacity and slightly higher voltage than 18650, without being much larger.
Being from Sanyo/Panasonic it is a ver good cell.



Notes and links

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 batteries
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That review was pretty quick after availability! Thanks for your efforts.

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That’s VERY interesting. Any idea since when Panasonic is producing these cells?
What are the current applications? Only Tesla?

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Tesla has decided on another size.

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Are you referring to 21700?

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Yes, that extra mm gives space for a bit more capacity.

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Wondering who is using this size of cells then…

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huge leaps in e bike battery capacity coming to e-bikes soon

Edit: HKJ, excuse my bad manners. Thank you for reviewing a battery of the latest model and size.

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Thanks for the review! Very interesting cell.

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thanks for the review,interesting that it can run so much current .

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Thanks for the review HKJ

We are to expect 21700 on the market too? It’s not clear to me from the articles on the internet.

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According to Henk4u2’s link Samsung has a 21700 cell

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Well with a piece of PVC pipe or a cardboard or some homemade thing we could use these cells in current 26650 lights that accept 26700 cells.will fit in 26650 charging slots as well.

Would be nice is a major manufacturer would develop the 26650 and we probably could have 7000mah 20+amp cells
Thanks for the review again HKJ your reviews are priceless and help save from purchasing some lemons for sure. Much appreciated the time out of your life you take for all the reviews

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thanks for the review, I enjoyed reading it.

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Thanks for the test. It’s not bad, but I can’t get excited until the price comes down substantially. At $10 each, it’d make big battery packs more expensive. Iirc, Tesla claimed 30% lower cost with their 21-70, which I’m hoping is per cell and that’d it’d be possible to buy them for less than $4 each in bulk. Even though this doesn’t put out a huge amount of current, it’d be good enough in a big battery pack, at least for electric bicycles.

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If they can provide ludicrous speed in a Tesla then they can power an ebike.

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Of course they can. 18650’s have been doing it for years. Anyone can build a fast bike. Affording it is a different matter. Building my own packs should save me about a thousand dollars…if I don’t burn my home down.

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Great!! This is an interesting direction for industrial cylindrical Li-Ion cells.

The ready access to these cells outside of industry buyers make me think, it’s possible this 20700 cell will be short lived as they standardize on 21700 going forward, although they can be considered roughly equivalent. It could also be though that since they are new there is not yet the industry demand to take up all production.

My cells are similarly wrapped and coded with a couple differences. The 4 digit code following the cell part number on mine is 6612; likely the date code. The code laser etched on the negative terminal is similar except the first digit preceding the U is separated from the group by the width of a couple of digits on a couple of them. This code is slightly different on each of my cells except 2 have the same code on the bottom. This leads me to believe this may code the specific factory, lot, and manufacturing machine specifics.

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It could go either way, or neither way. It largely depends on Tesla’s ability to meet their expectations. Several Gigafactories around the globe, and Tesla cars and Powerwalls in most new middle class houses would sway things heavily towards the 21-70. Occasionally sales will slow, and I have to think that they’ll open up sales of their batteries to secondary customers.

I thought they already started producing the 21-70, but that was just for testing, and even that only started last month. Today they started producing 21-70’s that’ll end up with customers.