Test/review of Sanyo NCR20700B 4000mAh (Red)

[SIZE=+3]Sanyo NCR20700B 4000mAh (Red)[/SIZE]



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.















[SIZE=+3]Conclusion[/SIZE]

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.



[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 batteries

Thanks for another great review. What markets do you think they are trying to target with this new cell size? For flashlights, I can't imagine too many manufacturers jumping on this when there are great 26650 and 18650 cells out there.

Mr. Tone said:

What markets do you think they are trying to target with this new cell size?

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Probably electric cars, but now Tesla has decided on another size I wonder if they will continue this size.

Mr. Tone said:

Thanks for another great review. What markets do you think they are trying to target with this new cell size? For flashlights, I can't imagine too many manufacturers jumping on this when there are great 26650 and 18650 cells out there.

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One potential market would be people who want a cell with more capacity than an 18650, but are uncomfortable with Chinese 26650s of questionable quality. But this will require that the cells be used with a spacer in 26650 lights and will result in a hit in capacity. Of course, it might also be possible to bore out SOME 18650 lights to accommodate this larger cell (in much the same way that Surefires are sometimes bored to accept 18650s). This would result in greatly improved runtime vs 18650s. And finally, the custom flashlight market might come up with options to use this cell.

^

Yes, some may design around it. It just doesn't seem like a gain of 400-500ma of capacity would be worth it, though. For me, the 5200ma of a good 26650 vs. the 3500ma of a good 18650 is a significant improvement in capacity. I guess this could turn out to be quite successful, though, since 40 S&W did very well and is here to stay.

Mr. Tone said:

^

Yes, some may design around it. It just doesn't seem like a gain of 400-500ma of capacity would be worth it, though. For me, the 5200ma of a good 26650 vs. the 3500ma of a good 18650 is a significant improvement in capacity. I guess this could turn out to be quite successful, though, since 40 S&W did very well and is here to stay.

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It would probably be a good idea to design for 21700, i.e. using a 22mm bore. This means slight lower diameter than 26650 and slightly longer, it would probably be a good size.

This battery looks to be almost exactly the same size as a No.8 battery so I will order a couple for my No.8 lights - hotwire mods.

HKJ said:

It would probably be a good idea to design for 21700, i.e. using a 22mm bore...

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I agree. The Samsung 21700 cell is rated at 4750 mAh and 9A max. The 1200mAh improvement in capacity over 18650 is substantial. A flashlight built around that size should still be easy to EDC.

It's not just the capacity improvement. Look at his comapator and out this against say a Samsung 30q. This cell has higher voltage along the entire discharge. And the 30q is basically unrivaled for this amongst 18650 cells

vicv said:

It's not just the capacity improvement. Look at his comapator and out this against say a Samsung 30q. This cell has higher voltage along the entire discharge. And the 30q is basically unrivaled for this amongst 18650 cells

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There's one 18650 that's better at maintaining voltage than the 30Q, and that's the VTC6. And it looks like this 20700 beats it throughout much of the discharge cycle.

True. They're so close though I don't think it makes much difference. And 30qs are easier to get. And I prefer Samsung cells

is it just me or is the font and production code different between these?
could indicate being made on different equipment and different time.
if so they have good consistency.

Mr. Tone said:

It just doesn't seem like a gain of 400-500ma of capacity would be worth it, though.

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You also have to keep in mind that this is also the first-gen 20700 cell, so the future ones will certainly be better while the 18650 li-ions seem to be nearing the end of their power density curve.

EDC-wise, the overall diameter of a flashlight is limited by its reflector rather than battery tube, so as long as a cell doesn't force it to exceed the reflector it used with a 18650-sized cell, it should have little to no bearing on its EDC value. For instance, some of the more popular 1x18650 EDCs of the last decade, such as ZL SC600 and SC60 series, Thrunite TN12 and Scorpion series, Fenix PD32 and PD35 series, etc., all have reflectors at least 3 mm wider than their battery tubes, so they could take a 20700 or 21700 cell without adversely affecting their pocketability.

I, for one, welcome our new 2*700 overlords. Surely hoping this will catch on ASAP.

Mr. Tone said:

It just doesn't seem like a gain of 400-500ma of capacity would be worth it, though. For me, the 5200ma of a good 26650 vs. the 3500ma of a good 18650 is a significant improvement in capacity.

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Another thing to remember here is that most 18650s are notoriously bad at delivering on their rated capacity (the VTC6 being an exception). For instance, the '3500mAH' NCR18650GA will only deliver 3208mAH at a 3A draw. The NCR20700B, on the other hand, delivers 3961mAH. So we can call it an honest to goodness 4000mAH battery. It's not 400-500mAH better. It's more like 750mAH better. THIS is significant.

Just for some fooling around I was able to drop this battery into some of my 26650 lights even without a sleeve as they are mostly dual spring design. Outside of testing though I would use some sort of simple sleeve. They worked in a DQG, G20, R40. It worked in the silly copper R50 as well, but since that one has no springs there was a gap at the tailcap and I would not really use it in that light. I suspect Sanyo will move to the 21700 designation soon, but it's just a guess.

Edit: ps. The battery fits in several of my chargers I tested it in, Opus, SV2, VP2, etc. Basically anything I tried it in except my very old chargers.

HKJ
Excellent review like always.
It will be interesting to see which size will become future standard - 20700 or 21700.

Panasonic NCR20700C. Samsung INR21700-30T will be good test contenders

space-cowboy said:

Panasonic NCR20700C. Samsung INR21700-30T will be good test contenders

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Don't forget the Ididn'tstarttheFire brand, which should come in around 11,500mAh

space-cowboy said:

...Samsung INR21700-30T will be good test contenders

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Is it available now for purchase from any of the usual sources?

markr6 said:

Don't forget the Ididn'tstarttheFire brand, which should come in around 11,500mAh

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:devil:

StorminMatt said:

Another thing to remember here is that most 18650s are notoriously bad at delivering on their rated capacity (the VTC6 being an exception). For instance, the '3500mAH' NCR18650GA will only deliver 3208mAH at a 3A draw. The NCR20700B, on the other hand, delivers 3961mAH. So we can call it an honest to goodness 4000mAH battery. It's not 400-500mAH better. It's more like 750mAH better. THIS is significant.

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That is a good observation, I didn't catch that.