The DELTA 3 Max Plus is a substantial unit with a weight of 22.1kg and dimensions of 494 x 242 x 305 mm. With a capacity of 2,048Wh, it has a large physical presence that reflects its role as a power station for home backup and off-grid use.

The build is robust, though the IP20 rating means it is intended for indoor or protected environments. As the top model in the DELTA 3 Max range, it features a large inverter and an expansion path to support demanding applications.

The interface includes four AC sockets and various DC ports, including an Anderson port which is useful for campervan setups. These components signal its position at the top of the DELTA 3 Max line as a unit capable of powering multiple devices at once.

The box contains the power station, one AC charging cable, manuals, and a warranty card. Solar cables and car charging leads are not included in the box and must be purchased separately for use with solar panels or vehicles.

The high-power output claim holds. Trusted Reviews measured inverter efficiency at approximately 87 percent across the range from 200W to 3000W.

This consistency is a notable strength, as many rival units see significant efficiency drops when operating near their maximum capacity.

For home backup applications, StorageReview measured a UPS switchover of 8ms against the manufacturer’s claim of under 10ms.

On the charging side, Trusted Reviews confirmed the manufacturer’s claim of reaching an 80 percent charge in 47 minutes on a UK unit.

The switchover is fast enough to keep a desktop PC or router running through a power cut.

Charging efficiency varies by input; Trusted Reviews measured it at 88.39 percent on a 2400W input and 90.46 percent on a 1200W input.

No independent test has verified the manufacturer’s claim of 4,000 cycles to 80 percent capacity.

The main caveat is that X-Boost is unavailable while the unit is charging from an AC source.

It remains a capable and high-capacity solution for home backup and off-grid use despite this specific limitation of its boost mode.

Darleene’s version: It provides reliable power for your home or van, with a switchover fast enough to keep your router running during a blackout.

The DELTA 3 Max Plus features an integrated UPS function with a switchover time of under 10ms and an X-Boost mode to support high-power heating loads.

StorageReview measured the UPS switchover at 8ms, which is fast enough to maintain power for devices like routers or desktop PCs during a blackout.

The manual states that X-Boost is unavailable while the unit is charging from an AC source and requires the grid input to exceed the load to ensure the battery charges during backup use.

At 2,048Wh this is more than twenty times the 100Wh limit that applies to batteries in hand luggage.

It cannot fly at all, in the cabin or in the hold, and no airline offers an approval route for a battery this size. That is the rule for every power station, not a quirk of this one.

That does not make it a stay-at-home product. It travels by road perfectly well, so it camps, it lives in a van, it goes to a festival and it goes away for the weekend, and it is the thing you want at home when the power is off.

If the trip involves a plane, the answer is a different class of product rather than a smaller version of this one. A power bank at or under 100Wh is allowed in the cabin and is built for exactly that job, and our best power banks and best power bank for travel pages cover them.

Full rules are in our can you take a power bank on a plane? guide. Check any capacity in seconds with our mAh to Wh calculator.

Capacity and recharge takes the highest score. It is a 2,048Wh LFP battery with an expansion path to 10kWh.

Two independent test sets, from Trusted Reviews and StorageReview, put about 80 percent of that rated figure at the sockets. They tested different regional units and landed in the same place.

The charging holds up. Trusted Reviews confirmed the claimed 80 percent in 47 minutes on a 230V unit, so that one is measured rather than repeated.

Power output and ports earned an 8 out of 10. Trusted Reviews measured inverter efficiency at roughly 87 percent across the load range from 200W to 3000W. Furthermore, StorageReview measured a UPS switchover of 8ms, which beats the manufacturer claim of under 10ms.

The fit for purpose score is lower because of practical constraints rather than performance failures. While it provides a quiet and reliable backup solution, X-Boost is unavailable when the unit is charging from an AC source, and the UPS mode requires the grid input to exceed the load to ensure the battery charges properly during use.

Value for money is the weakest score, and it is the one to read before buying. What you are paying the extra for is specific: the 3000W inverter, the expansion path to 10kWh, and the fast input. Rivals hold the same 2,048Wh without any of the three.

The expansion battery, the solar lead and the car lead are all bought separately, and the box holds the unit and a mains cable and nothing else. So if the reason for buying is 2kWh of storage and nothing more, this is the long way round to it. If the reason is the inverter or the expansion path, the score reads differently.