EcoFlow Delta 3 Max Plus Review

Design and Features

• Four AC outlets
• Smart app
• Expandable up to 10kWh

Although not much bigger than the EcoFlow Delta 3 Plus, the EcoFlow Delta 3 Max Plus packs in double the capacity, with 2048Wh. That’s impressive going, and a smaller case is always welcome, as it makes it easier to store the battery pack or transport it.

The one thing that EcoFlow can’t get around is weight, and the EcoFlow Delta 3 Max Plus is quite heavy at 22.1kg. In comparison, the Delta 3 Plus is a svelte 12.5kg.

There are two carry handles, one on either side of the battery. These are useful for one person to lift the EcoFlow Delta 3 Max Plus for short distances, such as into a car. If you’ve got two people, you can grab a handle at either side for moving this over longer distances.

If you want more capacity, then there’s an expansion port at the rear that lets you plug in additional batteries up to a maximum of 10kWh. At that level, the EcoFlow Delta 3 Max Plus could provide an average home’s power usage for a day.

One thing that has held portable power stations back is the maximum power output that they can handle via their AC ports. It’s typical for power stations to top out at around 2400W, unless you buy a bigger, more expensive model, such as the Anker Solix F3800, which has a huge 6000W output.

While the EcoFlow Delta 3 Max Plus can’t quite match that, it is rated at 3000W via its four AC outlets. That lets it power any standard single UK device, including a 3000W-rated kettle.

Surge power is rated at 6000W, so there’s some headroom, such as when an electric heater first turns on and draws more power initially.

There’s also the option to turn X-Boost on, which limits voltage and current to support a maximum output of 3900W. Not all devices are compatible with this mode and, given the high 3000W native output, you probably won’t need X-Boost.

UK power sockets are arranged in pairs. The outlets point towards each other, so larger plugs may obscure a socket nearby. Each pair of ports has its own power button.

There are then four USB ports. One USB-C rated at 140W, two USB-C rated at 45W and a single USB-A port rated at 18W.

There’s a screen on the side of the power station that shows the current charge state, and the input and output draw. Battery life is also shown in remaining minutes, so you can see at a glance how long’s left.

Connect the EcoFlow Delta 3 Max Plus to the app via Bluetooth or Wi-Fi, and you can remotely monitor the power station, and turn the ports on and off individually. The app also gives you a lot more intelligence.

If you’ve got a time-of-use tariff, you can set the power station to charge from mains power when electricity is at its cheapest. And you can tell the EcoFlow Delta 3 Max Plus how to use its AC ports in the event of a battery failure.

For example, you can set AC1 as Priority, such as for a fridge, which can fully drain the battery. AC2 can be set as Non-priority, say for a TV, and told to turn off when the battery hits 50%. 

Charging

• Variable AC input
• Up to 1000W of solar power

There are several options for charging. The default mode for the AC inlet is 2300W, which can get you an 80% charge in just 47-minutes. There’s a switch that changes the EcoFlow Delta 3 Max Plus between Fast (maximum) and Adjust (variable) speeds. Set to the latter, the App can be used to adjust the charging rate, which can be useful if you want to drop the charging rate, such as to maximise the amount of free energy you get from solar power at home.

Set via the app, the EcoFlow Delta 3 Max Plus was set to charge at 2400W, at which point it took 2317Wh of input to charge the battery, an efficiency of 88.39%. Dropping the input power to 1200W, efficiency increased slightly to 90.46%, but not by enough that it’s worth doing this unless you need to limit the power input for other reasons.

If you want to charge via solar, there are dual inputs on the side of the power station, with support for up to 1000W of power input. If you’ve got the panels (and the sunshine), you can get the Delta 3 Max Plus up to full capacity quickly.

Performance

• High efficiency at all loads
• Cheap per kWh of storage

Having 3000W of output is handy, and the Delta 3 Max Plus can easily handle most uses, or even tackle boiling a kettle, as I found out by maxing it out. More realistically, that level of power means you can run a washing machine or keep a big fridge freezer running in a blackout.

I tested the Delta 3 Max Plus at loads from 200W up to 3000W. Efficiency hovered around 87% at all levels, peaking at 88.33% with a 200W load. High 80% efficiencies are good to see.

Overall, the best round-trip efficiency (input AC power to output AC power) was 79.9%, which is pretty much bang-on the 80% that we like to see.

Using LiFeP04 cells, the Delta 3 Max Plus is rated for 4000 charge cycles before it hits 80% of its capacity. Assuming linear degradation of the battery, the power station would hold 7373kWh of power over this life span, which works out at a cost of 19p per kWh stored. That’s cheap as far as this kind of power station goes.

Should you buy it?