My lights stayed on. The aircon did too — even when the grid went dark.

Big battery, bigger ambitions

In the past, whole-home backup usually meant having a diesel generator running outside. But those days are fading for some homeowners. ZDNet's test of the EcoFlow Delta Pro Ultra X and the Smart Home Panel 3 shows how a battery system can replace a traditional generator for extended outages.

The main specs really stand out. The Delta Pro Ultra X (DPUX) scales from 12kW up to 36kW of output and offers between 12kWh and 180kWh of capacity.

Those numbers mean the system can handle large household loads — not just a few lamps and a fridge. ZDNet's reviewer, Maria Diaz, used the setup to run a 3,000-square-foot house during outages and kept two air-conditioning units and an oven working when the grid failed.

The Smart Home Panel 3 (SHP 3) is a key part of the package. It expands the circuit count to 32 and supports up to 200A, so it can replace a home's main electrical panel rather than just supplying a handful of essential circuits.

What happened during the blackout

Maria Diaz tested the setup during two outages in March while temperatures were high in her region of the southern United States. The system switched over in about 20 milliseconds, according to the review — fast enough that most electronic devices keep running uninterrupted.

The short swap time really makes a difference. A long switchover can trip sensitive electronics or disrupt smart home gear. The DPUX's automatic transfer time is in the same ballpark as many standby generators, yet it runs silently and without fuel deliveries.

In Diaz's testing, the SHP 3 replaced the home's main panel. That let the DPUX handle large appliances directly. Diaz reported the upgrade allowed two A/C units to stay on and the oven to keep running — loads that older backup panels typically couldn't take on.

How it compares to older EcoFlow gear

EcoFlow's previous Smart Home Panel—known as SHP 2—was designed for partial backup. It supported fewer circuits and up to 100A for essential loads. The SHP 3 almost doubles that capacity and increases the number of circuits from 12 to 32.

That matters if you want seamless whole-house backup instead of a critical-load-only approach. Diaz said she kept the SHP 2 in place rather than folding those circuits into the SHP 3 because doing so would have raised installation costs — a practical detail many owners will face during setup.

The DPUX also steps up from older EcoFlow home batteries. ZDNet describes it as more than a battery: a home battery, a generator alternative and a smart energy manager all in one. The reviewer said the system felt like running the house as if the grid had never gone down.

Mastheads

Usability, software and real-world trade-offs

To be honest, the hardware is just part of it. EcoFlow's app manages monitoring, power flows and settings. But ZDNet found the app far from intuitive, calling its layout confusing and some options hard to find.

That matters for homeowners who'll rely on the app during a stressful outage. Not just about toggling a few settings — it's about knowing what the system will prioritise when batteries drain and how to shift loads to avoid overloads.

Cost is another clear trade-off. ZDNet flagged the Delta Pro Ultra X as expensive to buy and install. The review didn't supply a single price tag — retail configurations vary with battery modules, inverter capacity and whether you add the SHP 3 — but it called the startup cost 'very expensive'.

The upfront costs definitely add up. Batteries, connectors, panel replacement and a professional electrician's time add up. Still, the appeal for many buyers is avoiding recurring fuel and maintenance costs tied to generators, and gaining a quiet, emissions-free backup that can integrate with home energy management.

Who should consider this setup

Whole-house backup isn’t necessary for everyone. For apartment dwellers or owners of small homes, a smaller power station or a critical-load panel might be the cheaper, simpler option.

But if you live in a large home with heavy loads — multiple air-conditioning circuits, electric ovens, heat pumps — the DPUX plus SHP 3 configuration is built for that use case. Diaz's experience in a 3,000-sq-ft house is an example: heavy HVAC systems stayed online and the family could carry on despite the outage.

It’s also a good fit for folks who want quick, automatic switchover without dealing with refuelling. The roughly 20ms transfer time is competitive with standby generators and is fast enough to avoid most interruptions in modern homes.

Installation and practical tips

You can’t just plug it in and go. The SHP 3 is designed to replace a main panel in many setups, which means a licensed electrician will almost always be needed. Diaz chose to keep an older SHP in place to avoid extra installation costs — a choice that shows how homeowners might mix and match to control expense.

If you’re thinking about switching to battery backup, make sure to get a few quotes. Ask electricians about whether your current panel can be replaced directly and what circuit prioritisation will look like during an outage. Also, check whether your home insurance or local regulations require certain wiring work.

And don't forget real-world limits: battery capacity determines how long heavy loads can run. A configuration sized for short outages won't power a house for days. Conversely, a bigger battery bank raises the price sharply.

Where this fits in the broader shift

Battery backup systems are becoming more common. Homeowners who used to choose between a generator and doing nothing now have a third option — battery-plus-panel systems that integrate with home circuits and energy monitoring. ZDNet's review shows one of the most capable options on the market right now.

That said, the user experience needs work. EcoFlow still has to polish the app and make settings easier to find. And the initial price tag will keep many buyers out unless incentives or falling hardware costs change the maths.

For people who can afford the jump, though, the benefits are tangible: quieter operation, no fuel deliveries and the ability to run modern loads under blackout conditions.

ZDNet gave the Delta Pro Ultra X a 4.5 out of 5 overall, praising its power and flexibility while noting the high startup cost and software rough edges.

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ZDNet rated the EcoFlow Delta Pro Ultra X 4.5 out of 5 and recorded a roughly 20ms automatic switchover during power outages.

This article was created with AI assistance.