How to Build a DIY Portable Power Station with an Apache Case & Lithium Battery

Three years ago, the team at B7 Homestead published their first DIY portable power station project, which quickly became one of the channel's most-viewed videos. After putting it to the test around the farm over the last year, it was time to design Version 2.0. This upgraded build fixes previous pain points by integrating a precise battery meter with a hardware shunt, cleaner internal cable management, better switch placement to prevent phantom power drain, and robust solar and shore charging capabilities.

Whether you need dependable off-grid power for camping, homestead chores, or handling unexpected power outages, this step-by-step guide and video walkthrough will show you how to put together a rugged, custom power box from scratch.

Project Overview & Key Features

Unlike off-the-shelf power stations that lock users into a closed ecosystem, this custom build relies on modular, easily replaceable components:

• Storage: Powered by a reliable WattCycle 12V 50Ah Battery.
• Charging Flexibility: Dual SAE inputs designated for solar panels and shore power.
• Outputs Galore: Dual USB-C PD fast-charging ports, a USB-A QC 3.0 port, and a 12V cigarette lighter socket.
• Smart Monitoring: Dedicated battery display paired with a hardware shunt for true state-of-charge tracking.

Complete Materials & Parts List

All components used for this build are standard off-the-shelf items. Note: Some links below are affiliate links that support the creator's channel at no extra cost to you.

• Battery: WattCycle 12V 50Ah Battery (Use code WTBLOG09 for special savings!)
• Solar Charge Controller: Amazon Link
• Battery Charger: Amazon Link
• Power Meter / Display: Amazon Link
• Switches: Amazon Link
• USB / USB-C Ports: Amazon Link
• SAE Connectors: Amazon Link
• Fuse / Circuit Protection: Amazon Link
• Wire & Terminals: Amazon Link & Amazon Link
• 12V Cigarette Lighter Plug: Amazon Link
• Protective Case: Apache 3800 Weatherproof Case (Available at Harbor Freight)
• Additional Hardware: Amazon Link

Step-by-Step Build Guide

Step 1: Case Layout and Panel Drilling

The build steps up from an Apache 2800 to an Apache 3800 case to provide extra room inside. Using a straight edge and a pencil, mark out the upper third of the box lid panel. Keeping cutouts in the upper third leaves ample clearance underneath for internal wiring and terminal blocks. Drill the holes carefully for the USB ports, cigarette lighter socket, rocker switches, SAE ports, and the battery monitor display.

Step 2: Weight Distribution and Interior Mounting

When carrying a power box by its handle, weight balance is critical. The heaviest component—the 12V 50Ah battery—must sit directly on the bottom and as close to the center as possible. Industrial PE foam tape secures the battery, solar charge controller, and fuse block to the bottom of the case, preventing shifting during transport over rough terrain.

Step 3: Electrical Wiring & Shunt Integration

Good wire management makes all the case builds cleaner and safer. Mount a fuse box featuring a built-in bus bar to protect each individual line properly. Crucially, install a hardware shunt between the battery’s negative terminal and the negative bus bar to ensure the battery meter reads true, accurate percentages rather than estimating based purely on voltage. Individual outputs like USB ports and the 12V socket should be wired through toggle switches to completely cut power and eliminate phantom battery drain during long storage periods.

Step 4: Testing and Troubleshooting

Before dropping the heavy battery into place, double-check all connections. Pro tip: Ensure switches are wired correctly between components and the fuse box/battery—placing a switch directly on a solar input line without isolating the charge controller can leave the controller drawing continuous idle power. Once wired properly, flip the master switches, verify that the Bluetooth solar controller and battery display light up, and tuck the battery securely into the housing.

Final Thoughts

Power Box 2.0 is modular, clean, and built to handle real-world homestead chores—from powering a 15-gallon sprayer on a golf cart to running lights in an unpowered outbuilding. If you are looking to assemble a dependable portable power system, check out the parts list above and follow along with the video guide!

Safety Warning: This project involves working with lithium batteries and high-current DC wiring. Always use proper fusing, correct wire gauges, and safe tools. Build at your own risk!