65W Power Bank Comparison
The battery life of my new Framework laptop isn't the worst, but it isn't super great either. But the cool thing is that it can easily be topped up with a power bank via USB-C. So I wanted one.
The Framework has a 61Wh battery. Having a power bank that can give it another full charge would be pretty great. The laptop charges at 65W so I looked at power banks that can charge at least that rate.
My goal was to find something compact and relatively lightweight. In the end I ordered three different models to try.
Capacity
All power banks are advertised with a milliampere-hour (mAh) rating.
This is quite confusing though. A typical power bank might use 4 cells. Each cell is rated at 5000 mAh at 3.6V. Mounted in serial, that results in 5000mAh at 14.4V or 72Wh 1).
But that power bank will not be advertised as a 5000mAh battery. It will be advertised as a 20000mAh battery because it's 4 cells with 5000 mAh. But that's not helpful because USB needs at least 5V.
If we divide the 72Wh by 5V, we get 14400mAh. Of course that's only in a world were Voltage can be stepped up or down without losses. The real world value will be lower.
I wish power banks would advertise the capacity in watt-hours (Wh) since that's the more useful unit. At least all tested models had their Wh rating printed in the small print on the device itself.
Measuring Capacity
Since the advertised ratings are hard to compare and because real world losses are to be expected, it's quite easy for manufacturers to bullshit their customers about the battery pack's capacity.
So I was curious if the claimed capacities would actually be reached in the real world.
To do so, I bought a cheap constant load thingy that draws 15W2) via an USB-A port and connected it to a cheap USB Tester. I then fully charged each battery pack, attached my test setup and measured the power consumption until the battery was completely drained.
This might not be the most scientific test. Especially with the cheap equipment involved. Losses might also be larger on higher power draws. But it should still be a useful relative comparison.
Baseus 26800mAh
This is the beefiest model I tested and it also has the largest capacity. At nearly exactly half a kilo this thing is a brick. It is also ugly as a brick.
The power button lets you toggle through the current state of charge, voltage and amperage on a simple, red LED display that is placed behind an ugly fish-eye lens. Functional but ugly.
It has 4 USB-A ports, 2 USB-C ports3) and even a Micro-USB port for charging.
The package also contains a 1m long USB-C cable.
- Capacity specified: 99.2 Wh
- Capacity measured: 90.3 Wh
- Efficiency: 91%
- Weight: 498g (5.5g per Wh)
- Price: 69.99€ (78ct per Wh)
Anker 20000mAh
Anker is a well known brand for chargers, battery packs and other related electronics.
This model is not as fancy as some of their other models. But it's weight to capacity ratio seemed to be slightly better. The simple display only shows the state of charge, no other info is available.
What sets this model apart is the integrated USB-C cable in the side. It can also be used to charge the battery. In addition there's another USB-C port and an USB-A port.
- Capacity specified: 72.0 Wh
- Capacity measured: 64.7 Wh
- Efficiency: 89.8%
- Weight: 472g (7.3g per Wh)
- Price: 39.99€ (62ct per Wh)
INUI 25000mAh
This was the one that made me think to actually test capacities. The device claims a high capacity but is actually the smallest and lightest of them all. Its specs seemed so outlandish that I just had to test their claims.
The first one I received came with a broken display. Not a good start, but I didn't want to give up too quickly, so I ordered a replacement.
Like with the Anker, the simple LED display only shows state of charge. No other info is available. The power bank is thick but still fits in the palm of my hand. There's a little carrying strap attached that is actually a small 15cm USB-C cable. I like that.
Unlike the other power banks, this one's fine print not only indicates a nominal capacity of claimed 90Wh but also says that the actual capacity, after conversion losses, is 80Wh. This means their conversion losses are either worse than their competitors above, or their given value is bullshit4).
- Capacity specified: 90 Wh (80Wh)
- Capacity measured:72.4 Wh
- Efficiency: 80.4% (90.5%)
- Weight: 383g5) (5.3g per Wh)
- Price: 66.99€ (93ct per Wh)
Summary
I wish INUI would advertise the capacity of their little power bank a bit more honest. Because it is a pretty good product. It's nearly 100g lighter than the one by Anker but still packs more power. I am a bit wary of their quality control and the battery's longevity but I am giving them a shot.
The Baseus gives you the largest capacity, but I only would recommend it if weight does not play a role. It's just a bit too unwieldy for my taste.
The Anker is just fine. It seems to me like the most boring option but in a good way. Anker is a well known, reliable brand and this model is just fine. The integrated cable is a nice additional touch. It's also the cheapest option.
