I do a lot of work away from an outlet and I wanted a way to keep the battery for my Porter-Cable impact driver and phone charged throughout the day. An old li-ion laptop battery was recycled for the power source and the Porter-Cable battery charger was modified to accept power from both AC input and the li-ion battery, selectable by the larger toggle switch. A fused IEC connector on the top connects to the AC input for the Porter-Cable charger and the charger for the Li-ion Battery. Two voltage regulators regulate power for the phone charger and a worklight located under the handle.
I’ve built this unit to provide silent power during power outages that usually result from large thunderstorms and hurricanes in my area. It contains a marine deep cycle battery connected to a 1000 watt Black & Decker inverter. The inverter is mounted to the enclosure for the battery to make it convenient to store and move. During Hurricane Irene it was able to power the fridge, lights, networking equipment, and netbook for more then eight hours without interruption. I would eventually like to add in a built in AC charger, 12v outlet and small light to make this box even more useful when the grid is not available.