Reliable power
for any need.
Create a solar power station for any use case, anywhere. This open documentation covers the system design and build of an affordable, battery-backed station for networks, monitoring, and automation.
Why build it?
OpenPowerBox brings reliable, moderate-scale power to networks, monitoring, automation, and field technology. Solar generation and battery storage support equipment that stays on around the clock alongside higher-power tasks that run when needed—all using standard components you can build into a system of your own.
A network across your property
Power wireless mesh nodes at multiple locations to connect cameras and sensors across large properties, farms, and remote worksites.
Video monitoring
Watch crops, wildlife, equipment, or an entrance. Add weather, soil-moisture, or tank-level sensing to understand what's happening on site.
Built for a wide range of devices, the system has a 15 W+ continuous power design target and 100 W+ intermittent output demonstrated in our pump tests. USB-C is our reference output; regulated DC or PoE can be designed in for other devices. Applications and output options →
Our estimate is that the unit can feasibly be made for under $500 in retail components, including tax and shipping, depending on your market, with the pole supplied separately. For context, a Tycon package with a 100 W panel and 600 Wh lithium battery is listed at about $1,183. At a sub-$500 build cost, that's less than half the price of this commercial package.
See the current budget and comparisonBuilt to keep going
The reference system is designed for 15 W+ of continuous power, with solar generation to cover daily use and battery reserve to keep equipment running through the night and changing weather.
Even under cloudy winter skies, the 200 W solar panel can provide meaningful power. Combining that year-round input with roughly 40 hours of battery-only reserve allows the system to sustain a 15 W continuous draw in San Luis Obispo.
Sustained storms can exhaust the reserve and interrupt output. With automatic load reconnection configured, the controller restores power once solar charging brings the battery back above its reconnect threshold.
Higher-power tasks can run for shorter periods while staying within the daily energy budget. Our pump testing has demonstrated 100 W+ intermittent loads; the output path and operating schedule determine how that capacity is used. How short bursts fit the budget →
Understand it. Build it. Use it.
Start with our build. Adapt it to yours. The reference design pairs a 200 W panel with a 12.8 V, 50 Ah LiFePO4 battery and a Victron SmartSolar MPPT 75/15 controller. A larger battery can add reserve; a larger array can improve recharge.
Our scaling examples explain what changes with the controller, wiring, enclosure, and mount as you change the system.
About the project
OpenPowerBox began as a Cal Poly Mechanical Engineering senior design project by Milo Goehring, George Konoval, Christopher Teo, and Joseph Phrachanhsay, with sponsor Eric Brigham. The goal is practical, open documentation for people who want to build and maintain their own small off-grid power system.
Download the user manual (PDF) · Testing & results · Source and page history