A stackable storage system is disclosed. The system includes a base storage container disposed on a wheeled cart, and one or more additional storage containers removably secured on top of the base container. The system further includes a power outlet box which is interchangeably securable in the system with the other storage containers. The power outlet box includes an extendable AC power cord which may be plugged into a wall outlet, and one or more electrical output plugs, include AC outlets and USB outlets which are powered by the AC power cord. The power outlet box and other containers are securable to each other by a spring loaded latch system. The power outlet box is also usable separate with a storage container having an overhead carry handle allowing both the container and power box to be transportable together.