There are basically two ways to charge a power bank. One is at home through as household plug which is the quickest and most efficient. Secondly, a power bank can also be charged via a solar panel. For those extra long sessions on the bank, it can be worthwhile to invest in a solar panel to top up the power bank while not in use.
Charging times can vary depending on a few factors.
Charging Speed – Different Cables and Ports can charge at different speeds. The same factors apply when recharging the power bank unit itself as with using it to charge devices. A regular USB cable will usually charge at a rate of 1A to 1.5A whereas a newer USB-C cable and port will double that to 2A to 3A thus cutting the charging time in half.
Good Quality Cables – Not all charging cables are built the same, it will be worth the effort and time to dig around and find a shorter high quality charging cable other than using the cheapest one available.
Size of Power Bank – is another factor to consider obviously, it will take longer to charge a 20,000 mAh Power Bank than a 10,000 mAh Unit.
Charging Devices while in Use – Power banks that have an output of 2A or greater can charge a device while it is in use. Although it will slow the charging process greatly.
There is a certain method used to extend the power output of your power banks. It is referred to as the 20/80 method. You will notice when recharging a device such as your cell phone that it rapidly charges from 20% to 80%. It takes a power bank more energy to charge a completely dead battery from 0-20% and to top up a unit from 80-100%. To maximize the lifespan of your power banks and other electronics it is recommended to recharge them before they drop below 20% power.