f you want portable power today, the consumer market forces you into a ridiculous compromise. You can buy a pocket-sized power bank that barely keeps a phone alive, or you can drag around a heavy plastic brick that takes up half your trunk just to charge a laptop. Major manufacturers insist that high capacity and high output require massive enclosures, thick empty plastic shells, and plenty of dead air space inside. The commercial electronics industry has convinced us that portable power stations need to be bulky boxes you dread carrying anywhere.
A power bank is small enough to carry around, but it generally won’t run anything much larger than a laptop.
Independent builder Gadget Industry looked at this manufactured bulk and decided to build something that actually makes sense. As Hackster.io reported, this creator engineered a homemade power station that provides more than 500W of total output while remaining small enough to hold in one hand. It packs a 300W AC inverter for desktop computers, alongside 140W and 65W USB-C ports for fast-charging phones and laptops. Commercial brands charge a premium for half that capability in a package ten times the size, while this garage build fits the entire electrical load into a custom dark green epoxy resin enclosure.
Inside the Handheld Power Monster
Getting desktop-tier power into a palm-sized housing required a complete tear-down of standard off-the-shelf components. Per Hackster.io, Gadget Industry started with four 3.2V, 15Ah LiFePO4 cells connected in series to form a 12.8V battery pack that reaches 14.6V when fully charged. These cells are rated for a 3C discharge rate, meaning they can supply up to 45A of current. A 100A BMS monitors individual cell voltages while providing balancing, overcurrent, and short-circuit protection, keeping the chemistry stable under heavy loads.
The real engineering gymnastics happened when fitting the electronics into a tight space. As Hackster.io detailed, the off-the-shelf 300W inverter module was simply too tall, so Gadget Industry cut the inverter PCB in half and reconnected the severed traces with jumper wires. Large capacitors were laid on their sides in the spaces between the cylindrical battery cells, the transformer was relocated to the opposite side of the pack, and the inverter’s MOSFETs were moved to a large aluminum heat sink. A 55 °C thermal switch turns on a cooling fan only when necessary, preventing wasted power and noise when the inverter runs cool.
USB-C Power and Real-World Stress Tests
The power delivery ports received the same aggressive space-saving treatment. According to Hackster.io, similar modifications were made to the 140W and 65W USB-C modules by desoldering and extending their connectors with wires so the boards could lie flat while the ports remained accessible on top of the device. The 140W module is bidirectional and doubles as the primary charging input. For situations without a high-output USB-PD supply, Gadget Industry added a separate boost converter and voltage regulator, making it possible to slowly recharge the battery from an ordinary 5V phone charger.
During testing, Gadget Industry powered a complete desktop PC from the AC outlet while simultaneously fast-charging two smartphones.
This garage-built device proves that multi-hundred-watt output does not require a suitcase-sized plastic shell. Big manufacturers pad their dimensions with empty air and oversized housings to justify higher price tags, but a single creator with basic resin and a soldering iron has shown that high-density power can fit in the palm of your hand.