This is a review of Astro E1 5200 mAh power bank. I had this for more than 6 months and have used it probably less than 30 cycles total. It’s still good to revisit the power bank and test the real numbers.
In a nutshell, this battery pack has a pretty good 77% efficiency and has great build quality. Recharging the battery is done at 89% efficiency, but this probably won’t matter too much for most users.
When looking at power banks, the important metric is the 77% efficiency, which means you can get 77% of the 5200 mAh capacity on tap when you are actually using the power bank. This battery is rated at 5200 mAh * 3.7V = 19.24 Wh. This is exactly what’s labeled on the power bank itself.
Now, looking at the usable power, 19.24 Wh * 77% = 14.81 Wh. This is the amount of energy you can expect to get out of the power bank. When charging your phone or another device, there will be another efficiency drop, so you can’t really directly compare the 14.81Wh available on tap with the battery capacity on your device. For example, from the list below, Galaxy S7 Edge has 13.86 Wh capacity. Since the Anker battery has 14.81 available, you could think that it will provide one full charge, but that is not the case. You have to consider the efficiency when charging the phone too, which I would guess at about 90% efficiency. So another efficiency loss for charging the phone will set you at 14.81 Wh * 90% = 13.33 Wh. 13.33 Wh is what you can expect that will go in to your S7 Edge, so it won’t fully charge the battery, but it’ll charge almost full to 96% (this is an estimate, assuming 90% efficiency on the phone).
For reference, these are the battery capacity for popular phones:
Galaxy S6: 9.81 Wh
Galaxy S6 Edge: 10.01 Wh
Galaxy S7: 11.55 Wh
Galaxy S7 Edge: 13.86 Wh
iPhone 6s: 6.55 Wh
iPhone 6s Plus: 11.1 Wh
iPhone 7: 7.45 Wh
iPhone 7 Plus: 11.1Wh
So again, if we assume there’s a 90% efficiency (or 10% penalty) when charging the phone battery, you can expect 13.33 Wh from this Anker Astro E1 when comparing the phone’s battery capacity. I would think it’ll fully charge the iPhone 6s twice.
When fully charged, the battery stops taking in charge which is good for the battery. Whenever you plug in the USB cable, the powerbank turns on and starts sending power out. If there’s no load, it’ll go back to off mode. There’s also a button on the side if you want to turn it on manually. This is useful if you had the USB wire plugged in but the device shut off due to nothing being plugged in on the other end.
When recharging the power bank, I measured 0.93A @ 5.1V, which is pretty standard for this capacity. On the label it shows it will charge at 1A, so that’s pretty close. A common pain point for smaller capacity battery packs (those 2000 mAh lipstick size) are that it recharges so slow at below 0.5A and ekes out less than 4 Wh usable power, that it’s not even practical.
Now, on to the build quality and exterior, I think Anker has very good build quality in general. I use several of their products and I’m never disappointed. The edges are smooth rounded and corners are nicely wrapped. No flaws anywhere and the lines align perfectly. The battery pack has some weight to it, which is one way to confirm it has good energy density packed in, and feels like a quality product.
Yes, I would recommend this to family and friends.
One more thing, this is a feedback to Anker, I’m kind of tired reading those lines “The Anker Advantage: join the 10 million powered…” being plastered on the first line of the product description. I think the first line should be useful information more about the product, not the brand. Also, it sounds very cheesy as in bad cheesy, but that’s just me.