Verdict
On its own, the Ecoflow Delta Max 2000 is handy, especially if you like to take your caravan off-grid when, say, staying at a festival.
Pair it with the Alternator Charger and it is far more convincing.
And for those of you who already have an Ecoflow powerbank, the Alternator Charger is a key add-on.
Pros
- Simple to install, useful secondary functions
Cons
- Weighty unit is not especially portable
A powerbank is just a battery in a box, with an inverter and some 240V and 12V sockets. This duplicates the systems your caravan has on board.
Now, Ecoflow’s new Delta Max battery-to-battery (B2B) charger aims to challenge this view. The Alternator Charger is a compact and stylish B2B charger that works solely with Ecoflow products.
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It comes with all of its cabling pre-terminated and everything you need to install it. To set up, connect the two terminals to your car’s battery (the positive is already fused), run it into the car, then plug it into the mounted unit.
A second wiring loom links the Alternator Charger to the standalone Delta Max powerbank. Now you simply fire up the app and you’re good to go.
The app has various options – you can have a traditional B2B charger where it recharges the Ecoflow battery at up to 800W (the powerbank runs at 40-60V, so this means up to 20A), which enables a totally flat Ecoflow powerbank to be charged in just a couple of hours.

In practice, it’s not quite that fast, however – smart alternators in modern vehicles vary the charge via the ECU – but it’s still quicker than a split-charge relay and recharges your Ecoflow while you drive. When you reach your site, you then have a handy power pack waiting to go.
The secondary functions are equally useful. As my vehicle hadn’t been used for a while, the battery charge wasn’t that high, so when I set the Alternator Charger to ‘reverse charge’ in the app, I was pleased to see the battery voltage zooming up.
No more messing with jump leads for a tow car’s flat battery.

As for the Delta Max 2000 powerbank: it has a 2016Wh battery, which equates to a 40Ah lithium battery (about the equivalent of an 80Ah lead acid). However, it runs at 50.4V, more efficient than running at 12V. It also has a 2400W pure sine wave inverter (supporting up to 3000W with an X-Boost function), with four 240V three-pin UK sockets, four USB-A outlets, two USB-Cs and a 12V cigar-style socket.
For any combination of devices plugged in, the display tells you how long the battery will last. At £899 it’s not cheap, but a good 2400W sine wave inverter on its own would cost £500.

At 22kg, the Delta Max 2000 is not that portable, either, but it’s ideal for powering devices under your awning or cooking up a meal al fresco.
I tested it with an 1800W air fryer before touring, then a 1500W fan heater in the van. It ran both without issue.
The major benefit of the powerbank is its flexibility and mobility – it can power almost any device, anywhere. It removes the potential worry of flattening your leisure battery when you’re off-grid, too – see our best caravan leisure battery guide if you’re after one.
Interested in a different portable power station? Check out our review of the Bluetti EB3A, a device that impressed Deputy editor Paul Critcher when he put it to the test.
Ecoflow Alternator Charger
- Charge: Up to 800W
- Connectivity: App & Bluetooth
- Weight: 2.3kg
Delta Max 2000 Powerbank
- Power: 2016Wh 50.4V battery (40Ah)
- Outputs: Four USB-A outlets and two USB-C
- Dimensions: 49.7 x 24.2 x 30.5cm (L x W x H)
- Weight: 22kg
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