什么 is a portable charger?
a portable charger, better known as a “power bank” is a device that has a sole purpose of being a power supply for devices like smartphones or 平板电脑. power banks have large batteries within them that are able to hold quite a large capacity.
电池的每一次充放电都会对电池造成一定的损失。以5000mah的充电容量和500次充放电为例；如果便携式充电器每两天充电一次，则可以使用1000天，大约3年。