Power Bank from laptop battery
Today, devices like the Power bank (stand-alone charger) have firmly entered our daily lives. They greatly facilitate the use of various modern energy-intensive gadgets, such as tablets and smartphones, as they allow you to quickly recharge in almost any conditions when you are away from an outlet.
The self-made powerbank scheme consists of three main parts. This is a lithium battery charge controller with auto-off function when fully charged; battery compartment with parallel-connected lithium-ion batteries of standard 18650; 5-10 ampere power switch from a computer power supply; boost converter in order to increase the voltage from the battery to the desired values of 5 volts, which are needed to charge the phone or tablet; USB connector to which the device is connected.