Power Bank Analysis - Baseus 20,000mAh 65W -vs- Charmast 26,800mAh 20W

JimmyLmao on 15/03/2023 - 14:56

So I did a bunch of maths - I hope this helps someone…

I was in the market for a power bank. I wanted it to be as close to 100Wh (27,000mAh) as possible, so it was the maximum capacity that can be taken on a plane without having to muck around with declaring it and getting it approved at customs.

I was mainly interested in the Charmast 26,800mAh 20W power bank ($59.99 via Amazon), thinking that its 99Wh capacity fit my needs best. Then I learned there's more to the story…

The Charmast has been tested to around 69% efficiency, while this Baseus 20,000mAh 65W ($47.99 via eBay) has been tested to around 87% efficiency. This does vary depending on charging speeds. Sources: 1, 2, 3, 4, 5

What does this mean?

Charmast ($59.99)
Dimensions = 19.71cm x 9.60cm x 1.42cm = 268.69cm3 volume
Weight = 430g
Advertised capacity = 26,800 mAh / 99.16 Wh
Actual output @ 69.30% efficiency, 14W PD charging speed = 68.72 Wh
Wh per gram = 0.16
Wh per cm3 = 0.26
Wh per $ = 1.15

Baseus ($47.99)
Dimensions = 15.40cm x 6.50cm x 2.70cm = 270.27cm3 volume
Weight = 450g
Advertised capacity = 20,000 mAh / 74.00 Wh
Actual output @ 87% efficiency, 65W PD charging speed = 64.38 Wh
Wh per gram = 0.14
Wh per cm3 = 0.24
Wh per $ = 1.34

In conclusion, despite the Charmast having 34% higher advertised capacity, the actual Wh discharged from the two power banks is similar. And they come in a similar size/volume and weight, so similar Wh output relative to their footprint. However, the Baseus is cheaper and thus offers more Wh output per $ spent.

Other advantages of the Baseus 20,000mAh 65W:
- Much higher charging speeds - useful for devices like laptops, iPads, Steam Decks, etc.
- Much higher input speeds, allowing the power bank to be refilled much quicker (compared to overnight for the Charmast)
- LCD display to see the exact remaining battery % (compared to no LCD, only 4 LED light indicators on the Charmast)
- Cycling the power button shows the volts and amps you're getting so you know your charging speed
- Comes with a USB-C to USB-C cable included (unlike the Charmast)

The one advantage I will give to the Charmast is that it has an input port for lighting cables, which means you can charge the power bank up with a lightning cable and then swap that same cable around to charge your iPhone. Haven't seen this on any other power banks - I imagine it could be pretty convenient!
Also returns via Amazon would likely be a far easier process if you run into any troubles.

In the end I decided to pick up this Baseus 20,000mAh 65W for $47.99 via eBay :)

Disclaimer: my maths and understanding of electricity may be wrong

Electrical & Electronics

Comments

  • mrkorrupt on 15/03/2023 - 15:14

    Advertised capacity = 26,800 mAh / 99.16 Wh
    Actual output @ 69.30% efficiency, 14W PD charging speed = 68.72 Wh

    vs

    Advertised capacity = 20,000 mAh / 74.00 Wh
    Actual output @ 87% efficiency, 65W PD charging speed = 64.38 Wh

    Please explain?
    14W PD charging speed = 68.72 Wh?????

    • JimmyLmao on 15/03/2023 - 15:27

      Sure thing.

      The data I found showed the Charmast to be 69.30% efficient when charging at a speed of 14W via PD, as the total Wh they were able to discharge out of the power bank was 68.72 Wh of energy. Actual output of 68.72 Wh divided by advertised capacity of 99.16Wh = 69.30% efficiency.

      The data I listed for the Baseus was at its highest charging speed of 65W, where the toal Wh discharged out was 64.38 Wh. Generally the slower the charging speeds, the less heat generated and energy loss from conversion. And visa versa. So the Baseus, and power banks in general, can be more efficient at slower charging speeds - the source said 90% efficient at 45W.

  • spackbace on 15/03/2023 - 15:41

    Or the 23,800mAh for $40 after coupon?

    How's that go with your sums? :P

    • JimmyLmao on 15/03/2023 - 16:12
      +1

      This site actually does have data on that exact Charmast 23800mAh 20W power bank.

      A fair bit more efficient at 74.49%, with at the same 14W PD charging speed test, for a total Wh output of 65.6

      So realistically I'd say it's the better buy compared to the Charmast 26,800mAh 20W, in terms of Wh output per $ spent. It is also decently lighter at 386g, with a smaller volume/footprint.

      Compared to the Baseus, if you only need a power bank for lower charging speeds and don't care about the extra benefits mentioned in the post above (at only $8 extra), then the Charmast 23,800 does have a better Wh output per $ spent ratio.

      Charmast 23,800 ($39.99)
      Dimensions = 15.40cm x 6.50cm x 2.70cm = 252.12cm3 volume
      Weight = 386g
      Advertised capacity = 23,800 mAh / 88.06 Wh
      Actual output @ 74.49% efficiency, 14W PD charging speed = 65.6 Wh
      Wh per gram = 0.17
      Wh per cm3 = 0.26
      Wh per $ = 1.64

    • berko_max on 23/03/2023 - 11:28

      How do you think that one compares to the INIU Power Bank, Slimmest 10000mAh for $30?

      https://www.amazon.com.au/dp/B07CZDXDG8/?coliid=IQV50KMXC1ST…

  • rumblytangara on 15/03/2023 - 16:41

    This is probably just me, but I would not buy a high capacity battery based around Lithium Polymer tech based on price.

    I've personally seen too many batteries swell to want one sitting in my house.

    • JimmyLmao on 15/03/2023 - 16:52

      Very good point. I didn't want to consider any dodgy, unheard of models for this exact reason. While Charmast and Baseus aren't Anker and Xiaomi, they're still pretty well reviewed and lots of data out there on them. If you've got the cash and want peace of mind, just go straight for the best!

      • neofelis on 07/04/2023 - 01:36

        Xiaomi is far from good. My 20000mah power bank displays E on the screen and is dead…
        Anker is good

        • JimmyLmao on 07/04/2023 - 12:36

          Oh no! My first ever power bank from 5 years ago was Xiaomi and just has only just recently started to play up / not hold a decent enough charge any more. I've got an upcoming overseas trip so I figured it was time to get a new one

  • keejoonc on 05/04/2023 - 10:12

    How did you even buy the Baseus 65w 20000mah powerbank on Ebay? It seems like it's sold out from every seller.

    • JimmyLmao on 05/04/2023 - 12:56

      Hmm maybe they're out of stock at the moment - you'll might have to look around other sites, or wait, or go with another option

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