Ditch the EG4 Mini Split: A DIY Solar AC Alternative

When it comes to solar-powered heating and air conditioning, many people immediately point to the EG4 solar mini-split. While it’s a decent product, I believe there’s a trick for getting far more bang for your buck and achieving energy independence with greater flexibility. I put together a system that not only powers my mini-split but also serves as a versatile portable power station. The best part? It’s super easy, practically plug-and-play.

Disclosure: OYLUS sent this unit for testing. All opinions and test results are my own.

What I Built

My setup involves a standard 12,000 BTU OYLUS mini-split heat pump, a powerful BLUETTI Elite 300 portable power station, and a pair of 590-watt bifacial solar panels. The OYLUS unit simply plugs into the power station using a standard 120V power cord. The solar panels connect directly to the BLUETTI Elite 300, which acts as the central hub for power management.

The beauty of this system is its simplicity. I did the entire mini-split installation myself, and it’s much easier than you might think. I even have a step-by-step video linked in the description below if you want to tackle it yourself. The portable power station can be located inside, with an extension cord running to the outdoor mini-split unit, allowing for optimal placement of both components.

Why It Works

The core of this system’s efficiency lies in the BLUETTI Elite 300’s intelligent power management. Unlike the EG4 unit, which directly ties solar input to the mini-split with no battery buffer, the BLUETTI acts as an intermediary. Its app allows you to prioritize solar power first. This means it will use as much solar energy as possible to run the mini-split and, crucially, store any excess in its battery.

Once the battery depletes to a certain level, the system can seamlessly draw power from the grid. This battery buffer is a game-changer. It prevents solar energy clipping, ensuring you capture and utilize more of the power your panels produce. This translates to longer runtimes on solar, even into the night or during cloudy periods, before needing to tap into grid power.

Parts & Specs

• OYLUS Mini Split AC/Heating System: 12,000 BTU, 19 SEER2, 115V. Estimated cost: ~$500 (including tax and delivery).
• BLUETTI Elite 300 Portable Power Station: 2,400W output, 3,014.4Wh capacity. Cost: ~$1,121.84 (with coupon code and tax).
• Solar Panels: 2x 590W bifacial N-Type monocrystalline solar panels (SGN-590-BDG1 UL61730 CEC). Total 1,180W. Cost: ~$975.56 (with coupon code and tax).
• DIY 48V System Components (alternative): Temgo 51.2V 100Ah LiFePO4 battery (5.12 kWh) ~$799.99, Junbpaw-similar inverter ~$299, MPPT charge controller ~$119.99, 2x 200W solar panels ~$309.99, plus various fuses, wiring, and tools. Grand total for components: ~$1,646.

Math & Run-Time Numbers

During my testing, with the OYLUS mini-split set to its lowest cooling point (61 degrees) and running at full tilt, it consumed approximately 572 watts. My two 590-watt solar panels were bringing in about 669 watts of PV power, even without direct sun and optimal alignment. This meant I was net positive, putting power into the BLUETTI Elite 300 while running the mini-split entirely off solar.

The flexibility of this system means you can utilize the stored energy from the battery buffer for extended periods. If you choose the DIY 48V system with a 5.12 kWh battery, that’s enough capacity to run the 572W mini-split for roughly 9 hours on battery alone, not even factoring in continuous solar input.

Pros & Cons

Pros:

• Significantly more flexible than the dedicated EG4 system.
• Portable power station can be used for other applications (RV, camping, home backup).
• Battery buffer captures and stores excess solar, maximizing energy use.
• Potentially thousands of dollars in savings on HVAC installation costs if you DIY.
• Cost-effective compared to the EG4 mini-split alone.

Cons:

• DIY installation requires some tools and basic technical understanding.
• The DIY 48V system lacks the seamless app control of a portable power station for grid switching.
• Requires more individual components compared to an all-in-one unit.

When To Use This vs. Alternatives

This setup is ideal for homeowners and tinkerers who want efficient solar-powered climate control but also desire flexibility and multipurpose use for their energy investments. If you’re looking to cool or heat a garage, workshop, or even a small cabin, this system offers a robust and adaptable solution.

The EG4 mini-split is a fine product for those who want a dedicated, integrated solar AC unit and don't mind the higher cost and lack of portability. However, if you already have a large home solar system with battery storage, adding a standard, inexpensive mini-split and integrating it into your existing setup is a far more efficient use of your resources. You can add more solar to your main system or extra batteries for less than the cost of the EG4 unit.

Bottom Line

My testing clearly shows that building your own solar-powered mini-split system using a portable power station like the BLUETTI Elite 300, or a DIY 48V battery setup, is a smarter investment than buying a specialized solar mini-split like the EG4. You save money, gain incredible flexibility, and get a more robust energy solution that serves multiple needs beyond just climate control. It’s a no-brainer for those seeking true energy independence and value.

Final Wrap-Up

I hope this breakdown helps you make an informed decision about your solar heating and cooling needs. If you have any questions or thoughts on this setup, please leave a comment below. Your observations are always valuable. Don't forget to check out my other videos for more DIY solar and power station projects, and consider subscribing to the channel for more epic content!