It’s not often I review a product on this blog other than notebooks with Linux on them, but I’ll make an exception for the 72Wh Anker Prime power bank, because it has a number of features that made it very interesting to me, and a few quirks that are not mentioned in the advertising. I bought this power bank, as the one I bought 2 years ago is limited to USB-C 60W Power Delivery (PD) and there has been a recent application for which I needed at least 100W PD. So I looked for something new and ended up with this one, which can deliver 100W on each of its 2 USB-C connectors. So here’s how it performs for me in practice.
General Info
So let’s go for the general stuff first. The official name of the product is ‘Anker Prime 20.000 mAh Power Bank (200W)‘, which is a bit clunky. On the bottom, the model number is given as A1336. As the full name implies, the capacity of the power bank is 20.000 mAh, which translates into 72Wh. Compared to my previous Anker 72Wh battery which weighed 620g, this model weighs 520g and comes with a color display that shows the remaining capacity percentage, current discharge or recharge power for each port, cell temperature, number of recharge cycles and a few other things. A very nice and useful feature. From a cost perspective, I paid €80 including tax for it, which is 16 euros less than I paid for my older power bank two years ago.
Efficiency
So far so good. The main feature I was of course interested in was the USB-C 100W Power Delivery (PD), and it indeed performs the job very well. Of the 72Wh promised by the specifications, I can retrieve around 60Wh with a discharge rate of around 22W. That’s a charge/discharge loss of 16%, which I guess is a typical value.
I don’t have a lot of devices that require a continuous 100W to test the maximum output power, but the power bank charges my Lenovo T14 Gen 2 notebook nicely with 70W, which is the notebook’s limit. At such a rate I could get 57Wh out of the original 72Wh from the power bank, so only slightly less than the capacity when discharging with 22W. Also, it was good to see that the power bank delivered the full 70W until it had to shut-off.
Charging Discharging Behavior
Anker says the power bank can be charged with 100W. In practice, that is true, but only from 0 to 30% of the power bank’s capacity. After that, it throttles down the recharge power to 50W. That’s probably got something to do with the cell temperature, which climbed to 44 deg. Celsius when it throttled down. To make sure the power reduction had nothing to do with the charger, I ran a charging cycle with a Dell charger and another cycle with an Anker 100W PD charger. The behavior was identical, so it’s definitely the power bank that throttles down. I’m glad I checked this, because I was about to buy another 100W charger to take with me on my travels. However, the time gained compared to a much lighter and smaller 65W PD charger is small, so I chose to go for the smaller, lighter and less powerful charger instead of the 100W model.
Another interesting quirk is the remaining charge shown as a percentage on the display. When charging, the display shows 100% after recharging 60Wh. However, behind the scenes the battery keeps charging at 50W for another 10 minutes before throttling down during the last 5 minutes. In other words, it kind of ‘cheats’ 15Wh. How strange!? Total time to charge from 0 to the real 100% capacity takes 1 hours and 35 minutes with a 100W charger and the throttle down from 100W to 50W after the first 30% of the charging cycle.
On the discharging side, the capacity percentage on the display works more accurately. The battery only shuts off when 0% on the display is reached, so there are no early surprise shutdowns. Another nice feature of the display is that it shows the current charge or discharge power in Watts for each of the two USB-C ports and the USB-A port. I checked the values shown with two different external USB power meters and the values matched pretty nicely with a deviation of a Watt or two.
And finally, one more interesting feature of this power bank is that it can be charged while at the same time supplying power to other devices. More about this particular feature in the next post.