The knowledge about mobile power supply

If you're someone who frequently forgets to bring a power bank when heading out, then you should pay attention to some of the lesser-known secrets about these essential devices. Let's see how much you know about them.

Just because a power bank has a higher discharge current, it doesn't necessarily mean that it can charge your phone faster. The charging current of a phone is determined by its own charging circuitry, and as long as the power bank's discharge current is greater than the phone's rated charging current, it can charge the phone at its maximum rate. For example, iPhones charge at 1A and iPads at 2.1A. If a power bank has a discharge current greater than 2.1A, it can safely charge either device.

The larger the charging current, the faster a power bank can be fully charged. Most power banks have charging currents between 1A and 2A, but some may falsely advertise higher currents. Consumers can use the aforementioned method to verify the true charging current.

The battery capacity of a power bank is usually marked on the device's shell, such as 10400mAh, which represents its total capacity. The larger the capacity, the more times it can charge a smartphone. Most mainstream power banks now have capacities of up to 10400mAh, but some unscrupulous manufacturers may use cheap batteries or fill them with concrete blocks.

Input voltage, which is usually marked alongside the charging current, indicates the voltage that the adapter outputs to the power bank during charging. The nominal value is 5V, but poor-quality adapters can damage power banks, with peak voltages reaching as high as 8V.

Output voltage, which is usually marked alongside the discharge current, has a nominal value of 5V. Poor-quality power banks may output voltages as low as 4V or as high as 12V, which can easily damage smartphones.

The battery type of a power bank can be either polymer or 18650. The latter, which is cheaper and more prone to explosions, is heavier, while polymer batteries are lighter and safer, but more expensive. Polymer batteries are gradually replacing 18650 batteries in power banks for safety reasons.

Efficiency is a critical factor that affects the temperature of a power bank and the number of times it can charge a smartphone. High-quality power banks typically have charging and discharging efficiencies greater than 90%.