The EcoFlow Delta II Max is an innovative new solar generator that is packed with features for off-grid power and emergency preparedness. EcoFlow has built upon the success of their original Delta line to create a mid-weight unit with increased capacity and improved performance.

The Delta II Max features a 2,048 watt-hour lithium iron phosphate battery, up to 3,000 battery cycles, and dual MPPT solar charging with up to 1,000 watts of solar input. With a 1,800 watt AC wall charger and expandable battery design, this unit provides substantial power in a compact yet rugged package.

This review will take an in-depth look at the Delta II Max solar generator. We’ll go through unboxing and specs, test solar and AC charging speeds, evaluate performance under heavy loads, examine long-term reliability, and compare to gas generators. The goal is to help determine if the Delta II Max is worth the investment for off-grid energy, emergency power, or van life.

Unboxing

As far as what comes out of the box with just the Delta II Max, you’re going to get the unit itself along with some paper documentation like a quick start guide and user manual. There’s also an AC cable for charging from a wall outlet, a 12V car charger, and a DC5521 cable that can be used for things like CPAP machines.

Frustratingly, there are no solar panel adapters included, requiring you to purchase MC4 to XT60 adapters separately. This seems like an oversight by EcoFlow given the small cost of including these adapters. All of the key specs are listed on top of the Delta II Max unit, and it comes with 4 USB-A ports, 2 USB-C ports, a 12V cigarette lighter port, and the DC5521 port.

Overall, the Delta II Max comes with most of what you need to get started out of the box. The lack of solar charging adapters is an unfortunate omission given the focus on solar charging, but otherwise it includes the key components.

Specs

The Delta II Max has a 2048 Wh lithium iron phosphate (LiFePO4) battery with a rated lifespan of 3000 cycles.

• It has a 2000W pure sine wave AC outlet capable of powering appliances and tools. There is also a regulated 12V cigarette lighter outlet and 2 USB-A ports along with 2 USB-C ports that offer up to 100W charging.

• For solar input, the Delta II Max has 2 MPPT controllers that can each handle up to 500W (15A) of solar input at 12-60V. This allows for a maximum solar input of 1000W to quickly recharge the unit.

• The Delta II Max is easily expandable through the addition of external batteries. It has two ports to connect up to two EcoFlow smart extra batteries to double the capacity to 4096Wh. The extra batteries neatly stack and lock into place for secure storage.

Design

The Delta II Max has a very portable and convenient design. At around 50 pounds, it’s light enough to move around and transport when needed.

One nice design feature is that the battery expansion unit is stackable. There are interlocking grooves so you can securely stack multiple expansion units or stack one on top of the main power station unit. This saves space and keeps everything neatly together.

The expansion battery also has a handy built-in storage compartment. You can store the connection cables or other accessories right in the battery unit itself, keeping them protected and easily accessible. The storage lid provides a flat surface as well, so you can even set things on top of the battery while it’s stored or charging.

Overall, the design is focused on portability, convenience, and usability. The stackable expansion batteries, built-in storage, and moderate 50 pound weight make the Delta II Max easy to move around and optimize in different usage scenarios.

Setup

Connecting the expansion battery is simple with the included XT150 cable. The expansion battery conveniently has a storage compartment on top as well.

When stacking the units, there’s a groove on the bottom of the expansion battery that locks into the main unit. This allows them to securely stack together.

I did encounter a tool icon on the main unit’s display showing an error or need for repair. However, after confirming with EcoFlow’s customer service and tech support, this icon can appear even with up-to-date firmware. It’s nothing to worry about.

Connecting the expansion battery is as easy as plugging into one of the two battery expansion ports. Once connected, a battery icon will show up on the display representing the expansion battery’s charge status.

The app also clearly shows the connectivity between the units and provides the combined output capacity. With the units linked this way, they can discharge and recharge between each other to balance the charge levels.

Solar Charging Tests

I set up an array of 3 rigid 200W solar panels and measured 56.5 volts open circuit. This was within the acceptable voltage range for the Delta II Max’s maximum 500W dual MPPT solar input.

I connected the panels to the PV1 input and achieved a maximum of 481 watts input power according to the display, which is over 95% of the rated 500W maximum. Excellent performance!

Using a DC clamp meter, I measured approximately 11 amps flowing through the negative wire. With 481 watts over 11 amps, this equates to about 43.5 volts under load, which is expected compared to the higher 56V open circuit voltage before connecting a load.

The Delta II Max efficiently harvests solar energy thanks to the dual MPPT controllers. The voltage and amperage aligned with expected parameters during testing. Based on the solar input performance, the Delta II Max is well-suited for off-grid solar charging.

High Power Testing

Next, I wanted to test the high power output capability of the Delta II Max. This unit is rated for 2400W of continuous output, so I wanted to see if it could actually deliver that in real-world use.

I connected the main unit to the expansion battery to utilize the full capacity. Then, I plugged in two high-power electric heat guns, set to around 1200W each. In total, this pulled nearly 2400W from the Delta II Max continuously. I let the heat guns run for over 25 minutes, and the EcoFlow system provided the full power the entire time without any issues.

This test confirms that the Delta II Max can sustain its rated 2400W output continuously without any drop-offs or cutouts. For running high-draw appliances like power tools, electric cooking devices, medical equipment, or anything else with a high power requirement, the Delta II Max is definitely up to the task. Even far exceeding the test duration, this system provides reliable power output at the advertised specifications.

Balancing Batteries

The Delta II Max and expansion battery are designed to auto-balance for optimal performance. When initially connected, you may notice the state of charge varies slightly between the two batteries. This is normal, as the main unit may be at 88% while the expansion battery is at 100% for example.

Over time, the batteries will communicate and balance out, with the higher charged battery discharging some power to the lower charged one. In my testing, I found the Delta II Max and expansion battery balanced to within 1-2% of each other after being connected for about an hour. The system handles this balancing automatically without any user intervention required.

The key things to watch for are if one battery stays pegged at 100% or 0% constantly, while the other hovers in the middle. In that case, a manual re-balance may be needed by charging or draining the outlier battery to match the overall system charge level before reconnecting. But typically, the Delta II Max handles all the balancing seamlessly in the background.

Overall, the auto-balancing is a nicely integrated feature that provides one less thing for users to worry about. Just connect up the expansion battery and let the system do its thing to keep the charge optimized across all batteries.

Solar Generator Term

The term “solar generator” is often used to refer to these types of systems, even though they don’t technically generate electricity like a traditional gas generator does. This term has become popular simply because it’s an easy to understand analogy that compares solar power stations to traditional generators.

It makes it simpler for people to grasp the concept – you have a box that provides power, much like a generator. So calling it a “solar generator” helps convey the core functionality, even if it’s not technically generating anything. The solar panels are generating, but the box is a storage device, not a generator.

Some people dislike the solar generator label as misleading. Alternative terms like “solar power station” or “solar battery” are more technically accurate. But solar generator has become the most widely used and recognized term.

The bottom line is that it’s a loose nickname that helps people readily understand the overall idea. It’s like saying “pass me a kleenex” when you want any facial tissue. Or saying “get in the car” when you’re actually driving a truck. It’s just a generalized term used for simplicity, even if it’s not being literal.

The specifics of lithium batteries and solar panels don’t really matter to most users. They just want an easy, portable way to store solar energy to power devices, and solar generator gets that point across. So that’s why the name has stuck, despite not being literally or technically accurate. It resonates with people and captures the overall concept in a simple phrase.

Preparedness Uses

The reason I like these solar generators is because of the security and long term effectiveness they provide for emergency preparedness situations. During a major grid down event like an EMP attack, you may be faced with months or even years without reliable electricity. Gas generators are useful, but fuel can be hard to find or store long-term. However, the sun comes up every day, and solar generators can run silently for a very long time without producing fumes or noise.

They provide a clean and quiet power source that can be operated safely indoors. You avoid the hassle of refueling and maintaining a gas generator. The batteries and solar panels in systems like the EcoFlow Delta 2 Max should last 10-20 years with regular use. This gives you reliable electricity day after day without any resupply concerns. For off-grid and emergency power, solar generators offer unique advantages over traditional generators. They provide independence, resilience, and long-term reliability that preppers need for any grid-down collapse situation.

Long-Term Reliability

The EcoFlow Delta 2 Max has impressive long-term reliability due to the high quality lithium iron phosphate (LiFePO4) battery and overall sturdy construction.

The LiFePO4 battery is rated to last for over 3,000 charge cycles while still retaining 80% of its capacity. This translates to many years of regular use before any noticeable degradation, especially if you follow best practices like avoiding full discharges and operating within the ideal temperature range. With proper care, expect over a decade of reliable power from the Delta 2 Max.

In terms of maintenance, the Delta 2 Max requires very little. There is no motor like a gas generator that needs oil changes or spark plug replacements. The sealed battery eliminates corrosion concerns. Mostly you just need to keep the unit clean, charged, and stored properly between uses. Firmware updates help keep things current. Overall, the Delta 2 Max provides power with minimal maintenance headaches for the long run.

Compared to generators that require gas, oil, tune-ups, and eventual engine rebuilds, the Delta 2 Max shines for low maintenance reliable power year after year. This makes it ideal for emergency preparedness and off-grid use where longevity is key.

Gas Generator Comparison

Gas generators have some pros and cons compared to solar generators.

Pros of Gas Generators:

• More power output – can run high wattage appliances easier
• Faster to refuel than recharge solar
• Can get fuel at gas stations if you run out

Cons of Gas Generators:

• Require maintenance like oil changes
• Produce fumes that can be dangerous indoors
• Noise pollution
• Fuel storage and rotation
• Limited runtime based on fuel supply

Pros of Solar Generators:

• Silent operation
• No fumes or emissions
• Lower maintenance
• Unlimited runtime with sufficient sun
• Modular and expandable capacity
• Can recharge from sun, AC outlet or gas generator

Cons of Solar Generators:

• Slower recharge times than refueling gas
• Lower peak power output
• Dependence on sunny weather

Overall, solar generators provide a clean and quiet power alternative with minimal maintenance. They can be combined with a gas generator for longer runtimes if needed, getting the best of both worlds. The modular nature and lack of fumes make solar generators ideal for indoor and silent operation during outages.

Fully Automated System

The Delta II Max can be easily set up as a fully automated system when connected to the EcoFlow Smart Generator. This allows the Delta II Max system to recharge automatically from the generator without any intervention needed.

To set this up, simply connect the Smart Generator to the second XT-150 port on the side of the Delta II Max. The two systems can communicate and the generator will automatically start charging the Delta II Max when the battery level reaches your preset low threshold, such as 10%.

The Smart Generator will continue charging the system until it reaches the high threshold you set, such as 80% or 100%. Once fully recharged, the generator will automatically shut off. The Delta II Max system can then resume normal operation, draining from the battery and collecting solar energy during the day.

This automatic recharging ensures the system never fully drains and allows it to operate continuously, even during extended weather events or grid failures. The quiet Smart Generator running occasionally in the background provides the periodic recharge the Delta II Max needs while avoiding the noise, fumes and hassle of a traditional gas generator.

Connecting the EcoFlow Smart Generator provides the ultimate automated backup charging solution for the Delta II Max system. With proper setup, you can enjoy endless off-grid power without any manual intervention needed.

Ongoing Testing

As always, I plan to continue testing the Ecoflow Delta 2 Max over many months to evaluate its long-term performance and reliability. My goal with all the power stations and solar generators I review is to identify any failures or decrease in performance over an extended period of real-world use.

I will be testing the Delta 2 Max through various weather conditions, charging and discharging cycles, and different loads. I’ll monitor the battery capacity and solar input over time to see if they degrade. I’ll also check that the outlets and ports continue functioning properly after repeated use.

My long-term testing will simulate real-world emergency and off-grid conditions, not just lab testing. I want to provide an accurate representation of how well the Delta 2 Max holds up for serious preparedness situations over many months or years of use. This type of long-term testing data is invaluable for consumers when deciding which solar generator to trust.

I’ll provide ongoing reliability updates and test results here on my website and social media. Be sure to subscribe to receive new videos and articles whenever I publish my latest findings after extended testing periods. I aim to be fully transparent about the pros and cons of each product over the long run. My goal is to equip viewers with the most comprehensive and unbiased reviews possible.

Recommendation

The EcoFlow Delta 2 Max is an excellent mid-range portable power station that packs a lot of useful features into a compact and portable package. Based on my thorough testing, here is my overall assessment of its best uses:

• Off-grid cabins and RVs: With 2048Wh capacity and 500W solar input, the Delta 2 Max can easily power most off-grid setups like small cabins or RVs. It’s compact enough to fit in tight spaces but has the power for essentials like lights, fridge, and electronics.

• Outdoor adventures: Bring the Delta 2 Max camping, hiking, or to the beach. It can charge phones, drones, laptops, cameras, and run things like mini-fridges and fans. The fast solar charging makes it easy to stay powered up on the go.

• Emergency preparedness: With silent operation and no fumes, the Delta 2 Max is ideal for home backup power during outages. Runtimes of 24-36 hours for a fridge and freezer mean you can safely store food and medications. Expandable capacity also provides long-term resilience.

• Remote work/events: The Delta 2 Max is great for powering equipment on remote job sites or at outdoor events. With fast AC and solar charging options, it can stay topped up and provide reliable power anywhere.

The Delta 2 Max is well-rounded for a range of uses where medium power capacity, solar charging, and portability are key. It provides great value at its price point and is easy to recommend as a mid-range solar generator option.