Although most of the power banks look very similar, they can vary a lot in terms of what’s inside them in terms of charging technology. This is why we cover the most important aspects for each model we review on our site:
Also known as fast charging, it is a technology that allows high levels of current flow over USB for filling the battery capacity faster, and subsequently reducing charging time.
The voltage and the current are boosted from typical USB rates (5V/0.5A) to produce values up to 100 W of power. Basically, during the initial charging phase, which is known as the constant current phase, a high current is pumped before the battery reaches its peak voltage. This is why fast charging is more efficient when the battery is below 50% of its total capacity. However, the charge controller regulates how much current and voltage a battery can take, and thus, prevent damages.
Many standards in the market offer a faster charging rate. Some of the most common ones are the Qualcomm Quick Charge, and the USB Power Delivery (USB PD), which is the official standard in any device with a USB port. Typical rates are:
Ø 5V/ 01 – 3 A
Ø 9V/ 1.67 – 3A (+ 27W laptops and other power devices)
Ø 15V/ 1.8 – 3A (+ 27W laptops and other power devices)
Ø 20V/ 2.25 – 3A (+ 27W laptops and other power devices)
However, different manufacturers use the USB-PD standard differently, such as Apple, which supplies 14.5 V and a current of 2 A for a maximum power of 29W, and it’s able to charge iPhone from 0% to 50% in 30 minutes.
This technology allows a power bank to charge another device while it is being charged itself. It works under the principle of prioritization, which in essence takes the power being drawn from an outlet and redirects it to the device connected to the power bank.
Passthrough charging provides USB- C ports that can be perfectly used with a wide array of the latest smartphones, as well as other high power devices. This can be a very useful feature for maintaining your power bank capacity full at all times, but unfortunately, not all power bank models come with it due to safety concerns.
Some models support wireless charging, which allows phones to get charged by simply being placed on top of the power, eliminating the need of using cables. In order for this to work, however, the smartphone should also support wireless charging.
Wireless charging works by transferring energy through electromagnetic induction. For this reason, a wireless charger uses a copper coil to create an electromagnetic field, which is received by the coil in the smartphone or device. In turn, the receiving coil transforms it into electrical energy to charge the battery.
The Wireless Power Consortium’s Qi standard has been adopted for all the major smartphones and gadgets, including the last version of iPhones, such as the iPhone 8 and the iPhone X. However, one drawback of using wireless charging is that it might take longer to fully charge the battery of your device as it cannot supply as much current as wired connections.
Some power banks come with photovoltaic panels to charge their internal battery, thus supplying renewable energy to charge smartphones and other electronic devices. This is a very handy feature for situations, in which you need power in remote places, such as at campsites.
Some power banks can only be charged by solar power, while others can support both regular charging and solar charging simultaneously; however, it isn’t fast so it might need to be charged through a cable as well.
Another disadvantage of solar power banks is that most of them are manufactured with small capacity, which means they should be used in case of an emergency.