On its own, the EcoFlow Delta Pro is a fantastic portable battery for those with bigger needs, featuring a huge capacity, fast charge, and the ability to power any household appliance, without compromise. But it also has enormous upgrade potential, from additional capacity to the ability to power a whole house with the Smart Home Panel. It's the most versatile portable battery yet, able to scale to any needs.

Specifications
  • Brand: EcoFlow
  • Weight: 48kg / 105lbs
  • Size: D64 x H41 x W29cm (25 x 16 x 11.4 inches)
  • Capacity: 3600Wh
  • Maximum Discharge: 3600W continuous (4500W in "X-Boost mode"), 7200W peak
  • Solar Controller: MPTT included up to 1600W input
  • Output: 4 x USB-A, 2 x USB-C PD, 4 x AC (UK/EU) / 5 x AC (US) , DC, Anderson
  • Input: 200 to 2800W AC configurable, and up to 1600W solar,
  • Maximum Recharge Count: Rated to 3500 cycles until battery is 80% capacity
Pros
  • Enormous upgrade potential
  • Handles any household appliance
  • Fast charging to full in less than 2 hours
  • Great for smaller solar installs (up to 1.6kW)
Cons
  • Big and bulky
  • Smart features are underdeveloped
Buy This Product

The EcoFlow Delta Pro pushes the definition of a portable battery into something capable of powering a small house or cabin, with an enormous capacity of 3.6kWh. It's also the world's fastest charging portable battery, able to fully recharge from AC in less than two hours. You won’t find a household appliance that can’t run on this, but if you do need even more capacity you can even expand it with yet more batteries. Read on to find out why the EcoFlow Delta Pro is the best choice for anyone who needs off-grid emergency power—without having to give up life's luxuries.

Delta Pro Dimensions, Weight, and Design

The Ecoflow Delta Pro is about the same size as a small suitcase, measuring 64 cm deep, 41cm tall, and 29cm thick. It also weighs an equally sizeable 48kg, or 105lbs. Though it is possible to carry it short distances thanks to the comfortable leather handles, I struggled to lift it up further waist height; and my wife couldn't get it off the ground. It's going to be a two-person carry in most cases.

ECOFLOW DELTA PRO- carrying

Thankfully, the hefty Delta Pro features large, sturdy wheels on the back—and just like a suitcase, it even has an extendable handle for rolling it around easily. However, they're quite inset, and I still found it awkward to wheel up a step or two.

ECOFLOW DELTA PRO- suitcase pullout

While the wheels and overall design are quite rugged and happy with rough terrain, it's not IP rated at all due to large air inlets, so you should avoid excessively dusty or wet environments. This isn't suitable for poolside or the beach.

ECOFLOW DELTA PRO- rugged wheels and dirty

Battery Tech and Pricing

Internally, Lithium Ferro Phosphate (LiFePo4, or just LFP) batteries provide 3500 charge cycles before degrading. This is superior to most backup batteries you’ll find on Amazon, which are rated to only around 500 cycles. Batteries degrade every time they're used, and the "3500 cycles" rating means that you can expect that after around 3500 full charge and discharge cycles, you should still have 80% of the original capacity remaining. Of course, this doesn't mean the battery is useless; just that it'll hold less charge than when it was new.

In terms of price, the EcoFlow Delta Pro retails at $3600 (£3400 / €3800) including delivery, so it's a nice easy $1/Wh. This is similar if not better value than other batteries of a similar capacity. The Goal Zero Yeti 3000X, for instance, is 3000Wh for $3500. But with the EcoFlow Delta Pro, you get added value from the app connectivity and additional expansion options.

ECOFLOW DELTA PRO- in frotn of solar panels

Ports and Plugs Galore

There are a lot of things you can plug into the Delta Pro, for input, output, and expansion. Starting with output:

  • Four AC ports on the 240v EU and UK model; for the US model there are a total of five AC sockets (four rated to 20 amps, plus a larger 30 amp)
  • Two USB-A 2.4 amp 12W ports
  • Two USB-A 18W "Fast Charge" ports
  • Two 100W USB-C PD (Power Delivery) ports
  • 12V10A DC carport (or cigarette lighter as they’re known here)
  • Two 38W standard DC ports
  • One Anderson 12.6V 30A port

The latter three of these output options are hidden away under a side panel, with only the more commonly used USB and AC sockets exposed on the front of the unit.

ECOFLOW DELTA PRO- output front

Clearly, that's a lot of output options, but it is still possible to overload the Delta Pro if you exceed 3600W total continuous output for a length of time.

On the input side around the back we have:

  • AC with configurable slow charging or turbo mode
  • Car charging
  • Solar (11-150V 15A max, XT60 connector)

Pull up the flap that covers the charging connectors, and you'll also find a helpful specs list.

ECOFLOW DELTA PRO- pull out charge stats

All the necessary charging cables are included in the package, with an MC4 to XT60 cable for solar, a thick IEC kettle lead for AC charging from a wall socket, and a carport to XT60 cable too.

Display

The display is big, bright, and easily visible in the sunshine, though the refresh rate makes it hard to capture a decent photograph so you'll have to take my word on that. On the right, it shows the current power in and out with four digits, and various other symbols to indicate that the fans are running and the frequency of the AC power. In the center, you'll find a large circle and two digits to indicate the percentage of battery remaining, while the left of the display shows a rough indication of how much time is remaining at the current rate of discharge. This only display two digits, so anything above one hour is a very rough estimate, but it changed to minutes remaining when it dips to less than one hour. It appears to average out the last minute or so of usage, so sudden spikes won't cause the estimate to oscillate dramatically.

ECOFLOW DELTA PRO- output front

The fans can be very loud and will kick in when doing anything above around 500W, whether that's charging or discharging, and ramp up accordingly. I measured up to 71dB when using the boosted full charge speed. It's enough that you'll have to turn the TV up if you're using it in the kitchen, for instance.

ECOFLOW DELTA PRO- noise levels

Charging the EcoFlow Delta

As hoped from this absolute unit of a battery, you can charge it very quickly indeed. First up, AC charging from a regular wall socket has two modes, which you can select using a small toggle switch next to the AC input, choosing between Fast and Slow.

On this 240V UK model, the fast mode is 2800W, so that will fully charge Delta Pro in around an hour and a half! The 120V version for the US appears to be limited to 1800W, which is still fast, but not as impressive. That'll charge in just over two hours.

ECOFLOW DELTA PRO- input

Slow mode is even more interesting as it's configurable from 200-1800W, which can be selected using the app. I tested this, and sure enough, a few seconds after changing the charge rate, the input wattage changed. Of course, depending on the charge rate you choose, charge time will be faster or slower. At the slowest rate, it'll take the best part of a day to fully recharge. This could be useful if you're staying somewhere with limited infrastructure—perhaps a long extension cable to your caravan that's only rated to 2kW; or perhaps you have a home solar system already installed and know that you have only around 600W excess being generated. You can limit the charge rate to suit your situation.

ECOFLOW DELTA PRO- customizable charge speed

A word of warning on the cabling (which is repeated on the velcro cable tie): this is a standard IEC cable (often called a kettle lead) that you'll find plugged into your PC, monitor, and other household appliances. However, the included cable is rated for a higher current than typical cables, so don't get them mixed. If you were to use a different cable, the fast charge high current mode would melt it, and potentially be a fire risk.

ECOFLOW DELTA PRO- charging cables dont mix up

Next, we have solar charging, up to a maximum of 1600W. In theory, you could fully charge from a maxed-out solar array in around two and a half hours. My home PV array is overrated at 3kW, so I bought a few new high-efficiency panels to test this out. My budget doesn't stretch to 1600W-worth, but I did try two 440W bi-facial LG panels. An MC4 to XT60 cable is included, so you can plug standard static roof panels such as these directly into the Delta Pro. However, if you have portable panels, which are typically equipped with an 8mm DC plug, you'll need to purchase a separate adaptor. Also, Anderson is not the same as XT60, though they look similar.

A quick lesson in solar wiring, since I got it wrong first: if you have multiple panels, you can wire them either in parallel (using a Y-splitter), or series (in a loop, with positive to negative terminals on each panel). Wiring in parallel will combine the current output of both panels. Wiring in series will combine the voltage. The EcoFlow Delta Pro is rated for 11-150V at a maximum 15A. The panels I'm using output a maximum 41V at 10A max. When I initially wired them in parallel, I was therefore potentially trying to put 20A into the 15A max. While this won't break the unit, it will limit the power. I achieved a maximum of 660W in good sun. That's good, but not ideal. Changing to series wiring instead kept the current at 10A, while the voltage combined to a potential maximum of 82V, which is well within the acceptable range. This brought me up to 770W in similar conditions. So do the math if you're planning to connect multiple panels, or you may find a lower than expected generation.

I'll also note that the minimum charge voltage appears to be higher than smaller batteries. I initially tested with some foldable 100W panels in less than ideal conditions, which registered around 30W on a small portable battery. The Delta Pro was unable to be charged from that. Once conditions were better, there was more parity with performance, both batteries showing 80W. It's not worth trying to charge the Delta Pro from such a low output portable panel. Even at 100W, it would take well over a day to fully charge—which means more like four days to a week of full sun.

Finally, although not possible out of the box, EcoFlow sells an optional EV XStream adaptor, which enables you to charge the Delta Pro from an electric car charging point, up to 3400W. If you have a free electric car charging point, or just the infrastructure at home that'll you'd like to charge faster from, this is a great option.

Delta Pro: Discharging and Output

As mentioned, the EcoFlow Delta Pro provides 3600W sustained throughput with 7200W peak, which is immense. It's easily enough to handle any household appliance you throw at it, though not all of them at once.

ECOFLOW DELTA PRO- fully loaded

To test this, I plugged in a dehumidifier (which turned out to not be all that powerful at just 120W), a space heater on full power (2400W), plus an air fryer at about 900W+. This pushed the total to 3650W, which is just over the stated capacity, but had no problem running for over ten minutes. The time remaining estimate also appeared at accurate with an estimated 50 minutes remaining.

ECOFLOW DELTA PRO- overload test

Next up I tried a full-size kettle (3.2kW), and tested out the overload protection by turning on the air fryer too, which took the total usage well into the 4000w range. It lasted longer than I expected—a good few minutes before it shut off with an overload error. At that point you can turn off whatever was causing the issue and reactivate the AC again.

The Delta Pro also features an output option called XBoost, which can supposedly power any single appliance up to 4500W, though compatibility isn't guaranteed for all appliances. Unfortunately, after scouring the entire house, I can't find anything any single thing which would use this much power. Presumably, there are some large workshop tools, like a MIG welder, that this might apply to.

You could feasibly run your home from the Delta Pro, if you were careful about what appliances were turned on at the same time. Clearly, this would be easier in a small cabin rather than a six-bedroom family home. But you should also know that the 3.6kWh total capacity wouldn't be enough for the average family home. Our average daily usage is 12kWh, which is above average for the UK. In the US, the average is 30kWh, probably due to air conditioning. So you'd need eight and a half of these fully charged for the average US household!

Expandability and Upgrades

There’s a lot you can add on to the Delta Pro through the myriad of connectors it has.

Firstly is connecting more battery capacity. While you can’t daisy chain two or three Delta Pros together, you can buy up to two additional expansion batteries, each of which is the same capacity again, so a maximum of 10.8kWh.

ECOFLOW DELTA PRO- side panel inputs etc

In order to use it as a whole-house battery you’ll also need to purchase a Smart Home Panel, which connects up to two Delta Pros to your consumer unit (each of which can have two additional batteries and an emergency diesel generator), for up to 25kWh capacity, with 10 separate output circuits. But we don't want to think about how much a fully maxed out system like that would cost. Realistically, if you only ever wanted to use this as a permanent house battery, you'd get better value from something like the Tesla Powerwall. It's still a pricey investment regardless, but better value in price per kilowatt-hour.

The beauty of the Delta Pro is the flexibility that a portable battery pack offers. Perhaps you rent and want to take the battery with you when you move; or just carry a battery or two down to the lakehouse for your summer getaway. With the Delta Pro, you can do that. It's modular, portable, and expandable—able to scale all the way from RV to full house battery system.

Smart Features

The unit features Wi-Fi and Bluetooth, which allows you to remotely turn on or off the AC and DC output ports from sleep mode, as well as view some interesting stats about usage. You also need the app to configure the dynamic charge AC charge rate, and enable XBoost output mode.

While these features are nice to have, and the app is well designed and responsive, I feel like there’s more they could have done with internet connectivity, particular when it comes to automation.

For instance, it’s limited to only manual control of AC and DC output; you can’t schedule this or connect it to a web automation service like IFTTT. You also can’t schedule or automatically adjust the AC input charge rate, which is disappointing for a few potential use-cases.

I have an overnight cheap tariff where the price drops from a daytime rate of 30 pence (~40 cents) to 7 pence (~9 cents) per unit for a period of four hours. With the Delta Pro fast charging mode I can easily charge the unit back up fully during that time, but it means using a mechanical timer on the AC socket, which is a little inelegant. Thankfully my tariff is a fixed time, but some tariffs are more flexible, with low cost or even negative priced energy at different times every day. Smart plug functionality built-in the EcoFlow directly would have been very useful.

I also would have liked the variable charge rate to be automated. At the moment, I have an immersion water heater that diverts excess solar energy that I'm not not using. It does this with a current sensor on the grid side of our electrical supply. If it detects energy flowing back to the grid, it heats the water proportionately, thereby using every bit of generated electricity. If the Delta Pro had IFTTT integration, I could automate charging this from the excess solar too. This feature is built-in to the Tesla Powerwall. Given the Wi-Fi connectivity of the Delta Pro and ability to upgrade the firmware, it's possible this will be added at a later date, and should be possible.

ECOFLOW DELTA PRO- app outdoors

Still, these are very minor quibbles. The smart features offered on the Delta Pro are leagues above every other portable backup battery out there; just not as good as the best full home batteries.

EPS Mode

The Delta Pro also supports automatic emergency mode with power pass-through, meaning you can plug it into an outlet as you would normally to charge, then plug in your appliances, and they'll run using the power from the wall socket, rather than the battery. If grid power goes down, the Delta Pro battery will automatically kick in and take over.

You might be more familiar with the term UPS (Uninterruptible Power Supply), but there’s a reason this mode is not marketed as a UPS. EPS mode is not "uninterruptible", because it will be interrupted briefly before the Delta Pro takes over (EcoFlow claims 30ms). For most household appliances, this isn’t going to matter. Your refrigerator won’t care if it's turned off briefly; your oxygen generator should start back up again straight away. However, your Network Attached Storage system or gaming PC will have unexpectedly shut down. So you shouldn’t rely on this for delicate electronics, or you may suffer data loss.

It's still an immensely useful function to have and means you're not stressing the battery purely for emergency use. Many batteries are not equipped with passthrough, so by using them this way, you're effectively charging and then discharging the battery cells constantly, leading to a lower overall lifespan.

EcoFlow Delta Pro: The Ultimate Portable Battery?

The EcoFlow Delta Pro plugs a gap between portable small capacity batteries—that are fine for a spot of camping—and massive permanent install house batteries. The Delta Pro can scale from powering a small cabin or camper van, up to a full family house, while still being portable. You don’t need to seek out low-power versions of things because it’ll even power things like a chainsaw microwave oven.

ECOFLOW DELTA PRO- design overview

What’s really impressive about the Delta Pro isn’t just the enormous capacity and absurdly fast charge rate (because those are incredible!)—it's the expandability. It's the fact you can add two additional batteries. It's the Smart Home Panel that gives you an emergency backup option to a grid-tied home. It’s that you can buy an adaptor to charge the Delta Pro even faster from an electric car charging station. Whatever your situation, the Delta Pro can adapt to suit it—without compromise.