Abstract: This invention relates to a portable case including a processor configured to control the portable case; a charging port; at least one output port; an adjustable energy storage system further including a battery printed circuit board (BPCB) including a plurality of battery packs connectors; and a central battery management microprocessor (CBMM); and a plurality of battery packs configured to be connected to the plurality of battery packs connectors and to provide power to electronic appliance connected to the at least one output port; a user interface configured to enable powering and monitoring of the portable case; and a recharging element, carryable by the portable case, the recharging element configured to be connected to the charging port and recharge at least one of the plurality of battery packs.