INIU 20,000mAh Power Bank Hits Record Low, Offering 22.5W Fast Charging

Q: Brands promise endless power, but what hidden conversion drain is secretly stealing up to forty percent of this battery's capacity?

The missing power is mostly lost in voltage conversion. A 20,000mAh power bank is rated at the voltage of its internal lithium cells, about 3.7V, but your phone charges at 5V or more. That step-up alone cuts the apparent capacity by more than a quarter. In energy terms, a 20,000mAh pack at 3.7V stores about 74Wh. If you convert that to 5V output, the theoretical maximum is only about 14,800mAh before any other losses. Then the boost converter inside the bank typically wastes another 8% to 20% as heat. After that, cable resistance and your phone’s own charging circuitry can shave off roughly another 5% to 10%. That is why real-world usable output is often only about 60% to 80% of the advertised rating. For a 20,000mAh model, that usually means something like 12,000 to 13,000mAh of practical output at the USB port, and in weaker designs it can be lower. In other words, up to around 40% of the headline capacity can disappear in conversion and charging losses. That also explains why a power bank advertised as enough for four charges may deliver fewer in practice, depending on phone size, fast-charging mode, cable quality, temperature, and whether multiple devices are drawing power at once. The honest spec to compare is watt-hours, not just mAh.

3 articles · Updated · Kotaku · Sep 18

INIU’s 20,000mAh portable charger has dropped to a record low price, putting a compact high-capacity power bank on sale.
The pack stands out by fitting roughly a deck-of-cards footprint while still delivering enough capacity for about four to five full phone charges.
22.5W USB-C fast charging and three total ports—two USB-A and one USB-C—let it power a phone, tablet and earbuds at the same time.
A 3-year warranty and a built-in flashlight add to its travel appeal, especially for long flights, camping or extended time away from outlets.