Abstract: Multi-functional power distribution unit transitionable between different configurations and form factors to perform various power storage and distribution functions. Conversion cap attaches to a top of an expansion battery to convert the expansion battery into the multi-functional power distribution unit. A three-point coupling arrangement safely connects two power connectors (such as spring-loaded) of the expansion cap to two terminals on the expansion battery. Slidable/rotatable handles provide a gripping area for carrying the device yet remain unobstructive when stored. The multi-functional power distribution unit expands a power capacity of a power supply and/or generator (e.g., a solar-based power generator) and/or charges the expansion battery in a first configuration with the expansion cap connected to the power generator. Upon disconnecting from the power generator, the multi-functional power distribution unit transitions to a second configuration providing a standalone power supply (e.g.