Review of the EcoFlow Delta PRO Smart Extra Batteries – Everything You Need to Know


Written by Oliver. Last updated:

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Up until very recently, the amount of electricity a solar generator could store was limited by the size and quality of its internal battery. This meant that a solar generator’s total storage capacity was a figure that could only ever move in one direction. When you bought a solar generator, you were stuck with those storage capabilities until even that limited storage capacity decreased due to battery degradation.

Over the last year, several of the leading solar equipment manufacturers have introduced expandable solar generators that can be connected to one or more expansion batteries.

Today, we are going to take a look at the highly advanced EcoFlow Delta PRO Smart Extra Battery System. Not only will we explain how these expansion batteries work and why they can be so beneficial for consumers, we will break down their specifications to see if they really are as effective and useful as EcoFlow claims.

What is the EcoFlow Delta Pro?

Before we get into our in-depth review of the EcoFlow Delta PRO Smart Extra Battery, it makes sense to quickly explain what the EcoFlow Delta PRO is and what it offers. After all, what good are expansion batteries if you are unfamiliar with the solar generator that they connect to?

The Delta PRO was released in late 2021 and it was designed to be a major upgrade over the brand’s incredibly popular Delta 1800 Solar Generator. Almost immediately after its release, the Delta PRO established itself as one of the most powerful and versatile solar generators on the market.

For starters, it features an enormous, built-in 3,600Wh internal battery. As we will explore in greater detail shortly, the Delta PRO is also compatible with multiple expansion batteries, so it is not limited to its already impressive 3,600Wh storage capacity.

What Does the Delta PRO Offer?

In addition to a high-capacity internal battery, the Delta PRO also contains a powerful 3,600W pure sine wave inverter. Users also have the option to link two Delta PROs to double the output power to a truly impressive 7,200W / 240V. This means the Delta PRO is truly unprecedented in terms of output power. It also means that you can use the Delta PRO for genuine, whole-home applications! In other words, by connecting two Delta PROs, you could potentially supply power to some of the most demanding electric appliances, like a clothing dyer, power tools, oven, well pump, and more, which means it can be a practical power source for an entire house!

Charging the Delta PRO’s massive internal battery is also incredibly fast and easy. Thanks to EcoFlow’s unique ‘MultiCharge’ feature, which allows you to charge with solar and AC power simultaneously, the Delta PRO can reach an input power rating of 6,500W, which is the fastest charging rate of any solar generator in the world!

The Delta PRO is also compatible with EcoFlow’s Smart Panel Ecosystem, which means you can fully integrate the unit into your home’s power system. When the power fails, your Delta PRO will automatically kick in and supply your home with power, so you will have access to electricity when you need it the most. Again, this explains why the Delta PRO actually is a practical option for whole-home backup.

The Delta PRO also features 12 output ports, including USB-C fast-charging ports and a 30A Anderson RV port. On top of that, the Delta PRO features a touch-screen display and it is Wi-Fi enabled, so you can easily connect it to EcoFlow’s user-friendly smart app.

So, What About the Delta PRO Smart Extra Batteries?

As mentioned, the Delta PRO was designed for expandability. Each Delta PRO can be linked to as many as two Delta PRO Smart Extra Batteries. When you consider the fact that each of the expansion batteries has the same storage capacity as the Delta PRO itself (3,600Wh), you begin to realize how much power this solar generator system is capable of storing.

By simply adding a single expansion battery, you can take your total storage capacity up to 7,200Wh, or 7.2kWh. Two expansion batteries can deliver a total storage capacity of 10.8kWh. This is an incredible amount of power for a single solar generator; however, where the Delta PRO Extra Battery System really shines is when you pair two Delta Pros with a complete set of expansion batteries.

When you upgrade the Delta PRO to its full potential by pairing two units with four expansion batteries and the home integration kit, you can reach a mind-blowing storage capacity of 25kWh!

This means that the Delta PRO can compete with whole-home solar backup systems, like the Tesla Powerwall 2, which can only store 14kWh of power! When you consider the fact that the Delta PRO’s robust and expandable storage capacity is only one of the exciting features it offers, it begins to make sense why it was considered to be one of the most advanced solar generators in the industry’s entire history.

How are the Delta PRO Smart Extra Batteries Charged?

The Delta PRO’s Smart Batteries are charged in the exact same way as the Delta PRO’s internal battery, which means they benefit from its incredible input power rating and its 6,500W ‘MultiCharge’ feature.

As long as the Smart Battery, or Smart Batteries, are connected to a Delta PRO, they will begin charging immediately. Once the Smart Extra Batteries are connected, they will charge and discharge in unison, which means the remaining battery percentage will be kept level across all units. This is a convenient feature, as it prevents one battery from wearing out at a different rate than the rest of the batteries in your Delta PRO ecosystem.

Just like the Delta Pro’s internal battery, the Smart Extra Batteries can be charged from six unique sources – AC charging through any standard wall outlet, EV station charging, solar charging, EcoFlow Smart Generator charging, 12V DC car port charging, and even wind charging through a turbine.

Of course, ‘MultiCharging’ means you can also charge the batteries from two sources at the same time.

How Fast Can the Smart Extra Battery Charge?

Naturally, the charge speed will depend on your chosen charge method. With that being said, it is safe to say that the Delta PRO and the Smart Extra Batteries charge incredibly quickly.

If you are utilizing the ‘MultiCharge’ feature to reach a 6,500W charging rate, you would be able to charge the Delta PRO and a connected Smart Extra Battery in just under 2 hours! If you opted for AC charging alone by simply plugging the Delta PRO into a standard wall outlet, you could charge a Smart Extra Battery in just 2.7 hours; however, this would require the Delta PRO to be fully charged ahead of time.

Other Delta PRO Smart Extra Battery Features:

Like the Delta PRO itself, each of the Smart Extra Batteries also sports a bright LCD display screen. This easy-to-read screen displays all of the information you could ever need at all times. This means you get input and output power readings, as well as the remaining charge as a straightforward percentage.

You can even read how much power is remains until the battery is completely depleted if it continues to operate at its current output.

The Smart Extra Batteries are also Wi-Fi enabled and compatible with the EcoFlow Smart App, so you can quickly check all of the information listed above from your smartphone or tablet. This is what actually makes the Smart Extra Battery “smart”.

Smart app integration is incredibly useful if you are using your Delta PRO Solar Generator Ecosystem to supply power to your entire home. You don’t even need to be home to check how your Delta PRO and the connected Smart Extra Batteries are performing!

Each of the expansion batteries also features a carrying handle and a convenient set of durable wheels, so you still retain the portability that you get with the Delta PRO itself. While they are still fairly heavy, they are far more maneuverable than a standard deep-cycle battery bank or power wall. This means they are a practical option for RV enthusiasts and anyone else that would like to have the option to relocate their home backup system when required.

Delta PRO Smart Extra Battery Specs

  • Capacity: 3,600Wh / 3.6kWh
  • Battery Chemistry: Lithium-iron Phosphate (LiFePO4)
  • Battery Cycle Life: 6,500 cycles to 50% battery capacity, 3,500 cycles to 80% capacity
  • Shelf Life: 1 year on a full charge
  • Dimensions: 25” x 11.2” x 16.4” or 63.5cm x 28.5cm x 41.6cm
  • Total Weight: 84 lbs / 38 kg


What Can You Use the Delta PRO Smart Extra Batteries For?

While you can certainly pair a single Smart Extra Battery with your Delta PRO to increase your total storage capacity, the real advantage of the Smart Extra Batteries is their ability to transform your standalone solar generator into a whole-home solar power ecosystem.

By connecting two Delta PROs using the EcoFlow Double Voltage Hub, you can achieve a continuous output power rating of 7,200W / 240V! This is enough to power even the most heavy-duty and demanding electric appliances, so you can fully meet your home’s electricity requirements with pure solar power.

While connecting two Delta PROs would double your storage capacity to 7,200Wh, which is impressive, this might not be enough if you are planning to meet your entire home’s power requirements, or if you live off-grid.

This is where the EcoFlow Delta PRO Smart Extra Batteries would really come in handy. Since the expansion batteries are less expensive than the Delta PRO itself, you can greatly increase your total storage capacity without having to break the bank. Not only are they relatively affordable, but you can also increase your storage capacity to a total of 25kWh, which is far beyond what was ever possible with a solar generator prior to the EcoFlow Delta Pro’s release.

You can take things to the next level with the new EcoFlow Smart Home Panel, which is pictured above. The Smart Home Panel acts as the heart of the entire Delta PRO home battery ecosystem, as it can connect up to two Delta PROs and four Smart Extra Batteries with ten home circuits.

This combination ensures that you will have uninterrupted power during blackouts and other emergency situations. It also means that you can use your Delta PRO system to manage your solar electricity use, so you can easily switch your home over to solar power whenever you desire.

This is really beneficial for those that are connected to the grid with a smart meter, as it means you can run your electronic appliances and devices off of solar electricity when power sourced from the grid is at its highest price. This lets you reduce the cost of your monthly electricity bills, so you can start to see some return on your solar generator investment right away.

Would We Recommend the EcoFlow Delta PRO Smart Extra Batteries?

If your power requirements exceed what a single EcoFlow Delta PRO can deliver, we would certainly recommend purchasing one or more Delta PRO Smart Extra Batteries.

Not only can they each store an impressive 3.6kWh worth of electricity, but they are also incredibly easy to use. You can simply plug them into your existing Delta PRO and double or triple your storage capacity in seconds.

The easy-to-read display screen and ability to connect the batteries to the EcoFlow Smart App are also nice touches. If you are looking for a simple way to introduce solar power into your home, we cannot recommend a complete Delta PRO solar generator ecosystem enough.

For those that are interested, complete Delta PRO solar kits, like this EcoFlow Delta PRO 10,800Wh Solar Generator HEX KIT, are a great option. The Delta PRO HEX KIT pictured above pairs the Delta PRO with x2 Smart Extra Batteries and x6 200W monocrystalline solar panels. In other words, you get everything you need to store and use a significant amount of solar electricity in one convenient package.

Overall, we cannot recommend the EcoFlow Delta PRO and its Smart Extra Batteries enough!

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