A portable power supply is exactly what it sounds like: a portable battery that you can take with you wherever you go, with outlets that you can use to charge and power your devices, without depending on a mains power supply. Unlike gas generators, the power comes from a rechargeable battery, which, depending on the model, can be recharged using an AC-outlet, car-port or solar panel. The battery then stores this power, ready to transfer into your devices when required.