Pass-Through-Charging Power Banks
Wouldn't it be practical to be able to charge your smartphone or tablet at the power bank, while charging the power bank itself? A single USB charger would charge the power bank and devices at the same time then. The solution is called pass-through charging or charge-through.
However, we would like to consider that even with the appropriate equipment, the pass-through usage should be temporary and not 24/7. Even premium models are therefore not a replacement for a UPS (uninterruptible power supply) or should even be used to serve as an intermediate store for solar cells.
Unfortunately, only a fraction of all USB batteries support this handy feature. Maybe also because the implementation has become more and more complicated in recent years, due to various fast charging technologies with different voltages and protocols (see USB-C Power Delivery). We have therefore decided not to trust the manufacturer's information, but to check the pass-through charging suitability. Batteries that provide less than 5 watts or less than 4.65V in pass-through mode are also not included in the list below.