D batteries vs 2170

Batteries and Chargers Rechargeable Batteries
1

If the best 2170 batteries are around 5,000 mAh and the average size D battery is 8,000 mAh (what is says online) why would anyone use the 2170?

2

1.5V vs 4.2V (3.7V nominal).

mWH = mAH • V.

So for a 2.5× difference in voltage, the difference in current would have to be as much to balance.

1W = 1000V • 1mA = 1V • 1A = 1mV • 1000A.

2 Thanks
3

ChatGPT here:

Alkaline D Cell Battery

Using the typical capacity range:

  • Lower end: 12,000 mAh×1.5 V/1000=18 Wh12,000mAh×1.5V/1000=18Wh
  • Upper end: 18,000 mAh×1.5 V/1000=27 Wh18,000mAh×1.5V/1000=27Wh

Energy Capacity: 18 to 27 Wh

NiMH D Cell Battery

Using the typical capacity range:

  • Lower end: 2,000 mAh×1.2 V/1000=2.4 Wh2,000mAh×1.2V/1000=2.4Wh
  • Upper end: 10,000 mAh×1.2 V/1000=12 Wh10,000mAh×1.2V/1000=12Wh

Energy Capacity: 2.4 to 12 Wh

Lithium-Ion 21700 Battery

Using the typical capacity range:

  • Lower end: 3,000 mAh×3.7 V/1000=11.1 Wh3,000mAh×3.7V/1000=11.1Wh
  • Upper end: 5,000 mAh×3.7 V/1000=18.5 Wh5,000mAh×3.7V/1000=18.5Wh

Energy Capacity: 11.1 to 18.5 Wh

  • 21700 Battery: Significantly higher energy density by volume (0.61 Wh/cm³), making it more efficient in terms of energy storage relative to its size. It is smaller and lighter, suitable for high-drain applications where compact size and high energy capacity are crucial.
  • Alkaline D Cell: Lower energy density by volume (0.423 Wh/cm³) but has a larger physical size, making it suitable for applications requiring long-lasting power without the need for frequent recharges.
  • NiMH D Cell: Lowest energy density by volume (0.135 Wh/cm³), but rechargeable, making it suitable for high-drain applications where reusability is more important than initial energy capacity.
3 Thanks
4

I’ve taken the liberty of using some of HKJ’s invaluable tests to see what the effective delivered energy is at a load of 1A respectively 3A.

Alkaline - Panasonic Pro Power D - 8,750 mWh - 3,788 mWh

NiMH - Ansmann D100000 - 11,737 mWh - 11,111 mWh

Li Ion - Molicel P42A - 14,523 mWh - 14,196 mWh

When raising the Amp’s, the results for the first (two) contenders will even be more devastating.
It’s like comparing the use of a 2 pound hammer with a 1l plastic Coke bottle.
If used for a serious application, the Alkaline battery will get weak at the knees very fast.

4 Thanks
5

I am assuming you are comparing a D alkaline with the 21700.

Lithium batteries are infinitely superior to alkaline.

They last much longer
They are rechargeable
Greater voltage =greater power
No leaks
And much much more.

Alkaline is considered dated technology.

6

We’re very glad to have you here, Mia!

7

2170 are magic batteries, small on the outside big on the inside.

8

Like a TARDIS.