This portable battery powered my whole home during recent outages and it's still $1,650 off

Maria Diaz/ZDNET

What's the deal?

The EcoFlow Delta Pro Ultra is down from $6,299 to $4,649 with a Prime Day deal that is still available. If you bundle with two 400W portable solar panels, you get a limited-time discount with a total price of $5,899.

Also: The best Prime Day deals still live

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ZDNET's key takeaways

The EcoFlow Delta Pro Ultra battery and inverter unit is available now for $4,649 after Prime Day, down from its $6,299 MSRP, while the Smart Home Panel 2 is available at $1,899.The single unit has a 6kWh capacity, 7200W output, and 5.6kW of solar input, allowing it to run an entire home, especially when stacked with other units for increased capacity.The Delta Pro Ultra is a decidedly expensive solution for a home backup system, and though portable, its hefty weight could affect portability. 

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A whole-home power backup system is a must for many, especially those in an area that's often affected by hurricanes or other natural disasters. But a backup system like the EcoFlow Delta Pro Ultra can be the perfect fit if you want to switch to solar energy, want a backup in an emergency, or shave a little money off your energy bill. 

Also: The best smart home devices of 2024: Expert tested and reviewed

Growing up in a developing nation located squarely in the Caribbean meant my family was used to constant power outages. Whether due to hurricanes or other macroeconomic reasons, power outages were a nearly daily occurrence in my upbringing, so when I decided to move to Eastern North Carolina, I knew I'd be getting a home backup system. 

View at Ecoflow

I was glad to learn that the house my husband and I purchased already had a generator, but I was less glad when we realized it wasn't in working order. Since moving here over two years ago, we've experienced about a dozen hours-long power outages when a power backup system would've come in handy. 

Going through power outages with three young kids isn't easy, especially during the hot summer months, so when I began looking for a whole-home power backup system, I was excited to test the Delta Pro Ultra. 

Once I got the Delta Pro Ultra and Smart Home Panel 2, we looked for an electrician prepared to tackle the installation task. The entire project -- installation of the subpanel, disconnection of the standby home generator, and installation of the 100 amp service wire to the subpanel -- took a duo of certified electricians about 8-10 hours. 

Maria Diaz/ZDNET

Since then, the EcoFlow Delta Pro Ultra has run like a well-oiled machine in our home in multiple testing scenarios, including simulated power outages. 

Also: This new portable power station from Anker is a definite head-turner

This impressive portable battery has proven to be like the Swiss Army Knife of home backup systems. It can be charged through AC power, solar panels, and gas generators. Solar energy users can use the DPU with existing rooftop solar panels or with flexible solar panels, so you could potentially go off the grid for days and continuously charge your EcoFlow Delta Pro Ultra with solar energy. The DPU allows for a solar input of up to 16.8kWh, which lets users connect up to 42 400W solar panels. 

Maria Diaz/ZDNET

This means you could also charge your DPU and use it during peak energy hours to save money on your energy bill -- all with little work. The EcoFlow app lets you schedule this so the battery takes over during peak hours, and your home automatically goes back to grid electricity at night when energy costs are lower. 

Testing the uninterrupted power switchover proved EcoFlow's claims to ring true, as the Smart Home Panel 2 ensures a fully automated whole-home switchover for our setup. We've had several storms that caused school districts to cancel classes and offices advising employees to work remotely, and it ended up being a great way to test the DPU and Smart Panel 2. 

Screenshot by Maria Diaz/ZDNET

When the first of these storms began hitting our home, the lights started flickering, and we went to prepare for a power outage. We knew an outage was a possibility, as we had been alerted by the energy company and have also suffered power outages with every major storm that has hit the area in the past two years.

The EcoFlow app shows that the Smart Home Panel 2 had already been preparing for the storm by ensuring the battery was fully charged. The power was only out for about 20 minutes during that storm. Still, the EcoFlow Smart Home Panel 2 and Delta Pro Ultra took over seamlessly, so much so that we didn't realize we were on backup power until a few minutes into the short outage. 

Maria Diaz/ZDNET

The Smart Home Panel 2 has 12 loads of circuit level control, and we used each one to ensure the Delta Pro Ultra serves as a backup for what we need in our home during an outage. Because we have an older two-story, 3,000-square-foot home with two A/C compressors and two furnaces, we couldn't load the DPU with the whole house. 

Also: The best portable power stations

Instead, we ensured that the following items were covered during a power outage: kitchen appliances, including the refrigerator, kitchen outlets, garage, some of the downstairs lights, the upstairs furnace, a medium-sized refrigerator, and four bedrooms and bathrooms.

Maria Diaz/ZDNET

This ensures that our kids can have a comfortable night's sleep during power outages, that we can cook, and that there will be a seamless switchover, where not even the Wi-Fi will be interrupted.

Furthermore, even though the EcoFlow Delta Pro Ultra lives in the garage connected to the Smart Home Panel 2, it's not limited to being a home backup system. We can still transport the portable battery to the backyard to power up devices or to the driveway to power the vacuum and carpet cleaners when deep cleaning the cars (ask me how I know). 

Maria Diaz/ZDNET

The Delta Pro Ultra is quite heavy, at a combined 186 lbs for the battery and inverter, but if you can fit it in your car or truck bed, it's sure to make a great addition to a camping getaway.

Also: Anker's new Qi2 MagGo Power Bank offers a bonus feature for iPhone users

Since the EcoFlow allows for stacking, you could scale up to 90kWh to power essential appliances for over a month. You could stack up to five DPU batteries under a single inverter and combine three stacks with the Smart Home Panel 2. Each extra DPU battery costs $2,399, another Prime Day deal that's still available.

ZDNET's buying advice

The EcoFlow Delta Pro Ultra's biggest downside is its hefty startup cost. But considering how expensive traditional generators for whole-home backup can get, not to mention follow-up maintenance costs, it's a good investment that could lead to potential savings, especially when combined with solar panels.

The DPU requires no maintenance and can run indoors safely, and its LFP battery and cooling system ensure temperature control. It's also a whisper-quiet solution, one that you can't even hear when under 2000W, a stark contrast to our generator, which you can hear down the block when turned on. 

As far as alternative uses for the DPU, you could even start a solar panel setup for your home on your terms with flexible solar panels that can be set up anywhere, use it as a power supply for an RV or off-the-grid cabin, or plug it into your home's manual transfer switch.