A mobile energy storage apparatus comprised of: a. at least one variable energy control device which converts DC to DC, AC to DC and DC to AC and b. at least one energy storage device (such as a battery) and c. a means to adjust said at least one variable energy control device to various electrical output powers and d. a means to connect said mobile energy storage apparatus to an EV (electric vehicle) or other device electrically and mechanically to enable transferring energy even when in motion and e. optionally a means for attaching various covers to said mobile energy storage apparatus to suit various applications. The mobile energy storage apparatus allows the transfer of energy to or from: an EV, a building or any other electrical facility or device and can be configured with built-in or attached to various power sources.