#### scrambler

##### Well-Known Member

It would be nice to know what 21700 cells are being used, because last time I compared the top 18650 with the top 21700, I could not find a big energy density gain per volume or weight (they do have other advantages).

Below were my calculations, feel free to point out any error on my part.

The highest capacity 21700 I could find was the Samsung 50E and the highest capacity 18650 was the Samsung 35E.

Ans so I calculated the following.

18650 Samsung 35E:

Dia 18.55mm x Length 65.25mm = Volume of 17,634 mm3

Weight 50g

Capacity 3.5Ah => 0.000198 Ah/mm3 and 0.07 Ah/g

Samsung 50E:

Dia 21.1mm x Length 70.7 mm = volume of 24,722 mm3

Weight 69g

Capacity 5Ah => 0.000202 Ah/mm3 and 0.0725 Ah/g

That is only 2% more Ah per volume and 3.5% more Ah per weight for the 21700 vs the 18650

So right now, I am not seeing a huge gain in either battery size or battery weight.

Am I missing something obvious here?

Below were my calculations, feel free to point out any error on my part.

The highest capacity 21700 I could find was the Samsung 50E and the highest capacity 18650 was the Samsung 35E.

Ans so I calculated the following.

18650 Samsung 35E:

Dia 18.55mm x Length 65.25mm = Volume of 17,634 mm3

Weight 50g

Capacity 3.5Ah => 0.000198 Ah/mm3 and 0.07 Ah/g

Samsung 50E:

Dia 21.1mm x Length 70.7 mm = volume of 24,722 mm3

Weight 69g

Capacity 5Ah => 0.000202 Ah/mm3 and 0.0725 Ah/g

That is only 2% more Ah per volume and 3.5% more Ah per weight for the 21700 vs the 18650

So right now, I am not seeing a huge gain in either battery size or battery weight.

Am I missing something obvious here?

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