PowerBank or laptop powerbank

POWER BANK

A power bank is a portable device that stores electrical energy and can charge electronic devices such as smartphones, tablets, and laptops. The term "power bank" is derived from the fact that these devices act as a "bank" for storing power that can be "withdrawn" or used to charge other devices.

Power banks typically use lithium-ion or lithium-polymer batteries as their energy storage medium. These batteries are rechargeable and can be charged using a USB or AC adapter. 

The capacity of a power bank is measured in milliampere-hours (mAh) and typically ranges from 1,000 mAh to 20,000 mAh or more. A higher capacity power bank will be able to charge a device multiple times before needing to be recharged.

Power banks come in a variety of sizes and designs, with some being small enough to fit in a pocket, while others are larger and may include additional features such as multiple USB ports, built-in flashlights, and even solar panels.

Power banks can be very convenient, especially when travelling or when a device's battery is running low and a power outlet is not readily available. However, it's also important to be aware of the safety concerns associated with power banks. 

Using a power bank that is not properly certified or made with low-quality batteries can increase the risk of fires or explosions. It's important to purchase a power bank from a reputable manufacturer and to use it according to the manufacturer's instructions.

The efficiency of the power bank also play important role, when it comes to conversion of input DC to output DC via internal circuit and decide how much power will be left behind after charging the device. it should be in range of 80-85%.

It's also important to note that not all devices can be safely charged using a power bank. Some devices, such as laptops, may require a specific type of power bank or may have a maximum charging rate that is not met by a standard power bank.

When not in use, it's best to store power banks in a cool, dry place and to keep them away from extreme temperatures, as extreme heat or cold can damage the battery.

Overall, power banks can be a useful device for keeping electronic devices charged on the go. However, it is important to purchase them from reputable manufacturers, use them safely, and store them properly.