This battery is a BEAST and surprised me with its design. This is coming from someone who has reviewed over a dozen battery brands, including Goal Zero, Jackery, BigBlue, Rockpals, Aimtom, and the like. Goal Zero and Jackery are two of my favorites, but this Ecoflow surprised me indeed and has skyrocketed to one of the top brands I have tested and used thus far.IN A NUTSHELLThe EcoFlow Delta Pro packs so many features and nuances, it took a surprisingly long time to summarize my thoughts for this review. It is one HECK of a beast of a power station! Although I was not able to test many of the capabilities due to my limited budget, reading and researching about some of the functions kept me in awe.Goal Zero had been the gold standard for a long time with its market leading quality, safety record, and philanthropy roots, but the Delta Pro definitely should put the company on notice with an ecosystem that surprisingly surpassed Goal Zero's in many ways. Offering a 3,600Wh battery capacity that could be expanded to 25,000Wh nearly doubles what Goal Zero could currently offer at 15,671Wh, and its AC inverter leapfrogs Goal Zero's 2,000W of continuous power and 3,500W surge with double that: 3,600W and 7,200W, respectively. What that translates to is more devices and appliances that can be left running for many more days than homes with the Tesla Powerwall or large LG batteries commonly paired with home solar panels.Specifications and numbers aside, the Delta Pro has an impressive set of input (charging) options, including AC wall, EV charger (a first!), solar, DC-producing gas generator, and possibly a wind turbine in the near future. What wowed me was the rapid charging capability when specific EcoFlow products are combined: 6,500W! Goal Zero's best only charges at 600W, and two years ago, THAT number dropped my jaw. Charging a Delta Pro and Smart Extra Battery (7,200Wh) at 6,500W would take them from empty to full in less than 2 hours — SUPER impressive! Goal Zero's 600W would have taken over 10 hours.What additionally sets the Delta Pro apart is its Double Voltage Hub that can double the capacity and output of various Delta Pro product combinations. Tack on the Solar Tracker that uses a top-mounted sensor to follow the sun for maximum exposure, a Smart Generator that uses gasoline to produce DC power to directly feed into the Delta Pro, and you have a good support system to maximize battery capacity to run appliances with for longer, if not infinite, time periods.A large, colorful display provides information about the battery's status, and although it is beautiful, it lacks the details that Goal Zero's higher-end products provide. EcoFlow makes up for that with its gorgeous smartphone app that also tracks historical data to help the owner make a variety of decisions from.I really like the telescoping, retractable handle built into the EcoFlow: extend it to one of two lengths to tilt the battery backwards, then pull and roll the 99-pound Delta Pro across the house — at least, that's the theory. Dragging the heavy battery on uneven grounds (like gravel) or traversing stairs is a huge challenge with the Pro's small wheels. Did you notice the weight I had just mentioned? Ninety-nine pounds is no joke for the average person to carry up a flight of stairs! Goal Zero's Roll Cart, on the other hand, with its larger wheels conquer those obstacles and surfaces with much more ease.The EcoFlow tries to shed some of its LiFePO4 battery weight and cost by using a mostly plastic exterior. Although the Delta Pro still looks quite nice, Goal Zero's Yeti X series is housed in a mostly metallic enclosure that helps dissipate heat and is more durable. Metal withstands impact force better than plastic, no doubt about that, but also adds weight. Two distinctive, exterior design philosophies each with their own pros and cons. Delta Pro is physically larger than the higher-capacity Yeti 6000X (6,071Wh), for some reason.What surprised me despite all the impressive features of the 3,600Wh Delta Pro, it still costs just a little more than the lower-capacity, 3,032Wh Goal Zero Yeti 3000x. That makes it a great value!Overall, it both pains and delights me to see the Delta Pro kicking Goal Zero's Yeti X line to the curb. On one hand, Goal Zero now painfully looks a bit outdated, and on the other hand, Delta Pro has set a new bar that slaps Goal Zero in the face to wake up and innovate. Competition is always good for the consumer, and so, Goal Zero, what will you do next? EcoFlow has a winning product portfolio on its hands that is difficult to beat.ANALYSISAs one of Time Magazine's "Best Inventions of 2021" under the "Sustainability" category, EcoFlow's Delta Pro power station deservedly turned some heads. It certainly caught my attention with its wide list of features, expansion options, and accessories primarily geared for home use. Market leader, Goal Zero, offers a similar range of products, but EcoFlow does so in a sleeker — and at times more innovative — package. The configuration options gave me some struggles to write about while researching the Delta Pro because there were so MANY, most of which I could not test because it would have cost over $30,400 to collect the entire ecosystem for the "full experience"!Bear with me! There is a LOT to discuss because of EcoFlow's vast ecosystem of products. I will attempt to summarize the important ones and how they work with the Delta Pro.Delta Max vs Pro: The Max is a smaller, lighter version of the Pro with less capacity at 2,016 Wh, a smaller AC inverter, and no transport wheels.BATTERY CAPACITYThe Delta Pro offers 3,600 Watt-hours of battery capacity — how long something can run for — that can be expanded with up to two EcoFlow Smart Extra Batteries (3,600 Wh each) for a combined total of 10,800 Wh simply by connecting them with a pair of cables. That could power a typical home drawing 750-1,000W of power per hour for 10-12 hours. Double that to 21,600 Wh by linking another set of Delta Pro and 2 Extra Batteries via either the EcoFlow Smart Home Panel or the Double Voltage Hub. Finally, this can further be expanded to 25,000 Wh through the use of a Smart Home Panel, 2 Delta Pros, 2 Extra Batteries, and 2 EcoFlow Smart Generators — a gas-powered generator that produces virtually unlimited DC output (as long as gasoline is available) for more efficient charging of the Delta Pro.Goal Zero can only store up to 10,871 Wh with a Yeti 6000X and 4 Yeti Tank Expansion Batteries. Let that sink in. The market leader is actually BEHIND in this area.EcoFlow's Smart Home Panel can power up to 10 electrical home circuits during a blackout, the Double Voltage Hub can double the Delta Pro's capacity with the addition of another unit, and the Smart Generator can provide gas-generated DC power to the Delta Pro for more efficient charging. Furthermore, the generator can directly be controlled by the Delta Pro so it would only be started when needed.POWER OUTPUTAnother area the Delta Pro shines at is what devices — and how many of them — it can power at the same time. Its AC inverter can operate at a continuous 3,600W of energy and surge up to 7,200W. If those numbers do not make sense to you, do not worry. I will go over Continuous vs Peak (Surge) in more detail later.You can throw a number of high-powered devices, like a home air conditioner, refrigerator, TV, laptop, and hair dryer at it with no problem whatsoever as long as their combined power usage does not exceed 3,600W. The Continuous output can be expanded to 4,500W with X-Boost, or 7,200W by combining 2 Delta Pros with either a Smart Home Panel or Double Voltage Hub.Goal Zero's flagship Yeti 6000X can only go 2,000W continuously and peak at 3,500W — numbers that were impressive and unheard of when the product was announced in 2020.BATTERY TECHNOLOGYThere has been a lot of debate on whether Nickel Manganese Cobalt (NMC) or Lithium Iron Phosphate (LiFePO4) -- both are Lithium-ion (Li-ion) -- is better. Goal Zero, Jackery, and most of today's power station manufacturers use NMC, but why do EcoFlow and Bluetti use Li-ion LiFePO4 when they are bulkier and heavier? They hold some important advantages over Li-ion NMC:- Safer, less volatile, and thus cheaper to manufacture- Charge cycle: 1500-2000 (10+ years)-- NMC: 20-25% capacity loss after every 500 cycle (6-10 years for up to 2000 cycles, after which capacity is vastly diminished)-- EcoFlow claims 3500 cycles before dropping to 80% of original capacity and 6500 to 50%. Those are some VERY optimistic projections that I do not think are accurate in actual usage- Usable in more extreme temperatures (-4F/-20C to 176F/80C). NMC: only 140F/60C max- Holds 350-day charge. NMC: 300AC CHARGING SPEEDSTip: A record-breaking input of 6,500W (!) can be achieved by combining AC + Solar + Smart Generator charging! (A Smart Extra Battery must be connected to the Delta Pro for this to work.)The back of the Delta Pro has a toggle for how much power it should draw for charging: Fast or Slow/Custom.- Fast: 1,800W (120V @ 15A) or 3,000W (240V @ 12.5A)-- 0-80% in 2 hours and to 100% after another 45 mins- Slow/Custom: 200W – 1,800W-- Slow charging is gentler on the battery, prolongs its lifetime, and minimizes risk of tripping the circuit breaker-- Custom allows the Delta to charge at a configured rate so the wall circuit would not be overloaded. That's an EXCELLENT feature to have!--- Example: If an AC Circuit can only handle 1,200W and a coffee maker uses 800W, then the Delta Pro should be configured to charge at no more than 400W (1,200W – 800W)-- Configurable through the EcoFlow appTip: AC charging is prioritized over DC when both are connected simultaneously. Never use an extension cord to charge the Delta Pro with unless it's a heavy-duty one.If the Delta Pro is used in pass-through UPS (uninterruptible power supply) mode, the internal circuit will turn off its inverter if it detects the AC wall outlet getting overloaded (ie. passing through more than 20A). This means that it could shut off at 1,200W without ever reaching its 3,600W capacity. To use the full 3,600W, disconnect it from the wall and let the battery provide that power.Note: Using a battery as a UPS (charging and outputting at the same time) could shorten its lifetime.PROS- Impressive battery capacity (3,600Wh – 25,000Wh)-- Superfast, configurable charging speeds (200W – 1,800W or up to 6,500W under specific conditions!)- LiFePO4 technology provides for 10+ years of power-- Up to 2,000 – 3,000 cycles based on my research (I do not believe EcoFlow's claim of lasting much longer than 6,500 cycles. Hope they prove me wrong 15-20 years from now!)-- Much safer and stable than Lithium-ion NMC- Large AC inverter with continuous 3,600W (7,200W peak) of output-- Enough to power a typical home for days — or, when used with the EcoFlow (Gas) Smart Generator and/or set of solar panels, virtually forever-- Pure-Sine Wave AC Inverter--- Clean power for sensitive electronics--- Less heat--- Note: Some manufacturers claim to be Pure-Sine when they are actually Modified or Square Waves- High-quality BMS (Battery Management System) for safety-- Provides built-in overload, overcharge (automatic stop when the device is full), and short-circuit protection- Expansion/augmentation ecosystem with EF Solar Panels, Double Voltage Hub, Smart Generator, Extra Smart Batteries, Smart Home Panel, wind turbine (not yet available), EV charging station, and Remote Control- Impressive input and output options, including a NEMA 30A for RV hookup-- Up to 1,600W of solar charging- Carry handle is strong enough to run a cable lock through for theft deterrence- Can be used in pass-through UPS mode, though that can shorten the battery's lifetime- Beautiful, large, color information display- Built-in, retractable handle- Wheels for easier transportation- Strong Research & Development and Engineering teams who create innovations that Goal Zero, Jackery/Generark, and Bluetti cannot ignore-- Competition hopefully continues to spur better products from all companies- Beautiful, informative EcoFlow smartphone app with historical data (for Apple iOS and Android)CONS- Heaviest power station (99 lbs) I have ever reviewed-- Weight is due to the use of 3,600Wh of LiFePO4 battery cells instead of NMC--- Comparison: Goal Zero, despite using a more heavy-duty, metallic enclosure, has the Yeti 3000X (3,032Wh) weigh at 70lbs, Yeti 6000X (6,071Wh) at 106 lbs-- Difficult to move up stairs, lifting onto truck bed, or pulling across gravel ground — especially with the small wheels- Plastic enclosure helps shed some weight but is not as heavy-duty as Goal Zero's Yeti X line- Bulkier than Goal Zero's Yeti 3000X and 6000X-- Although I was not able to borrow my friend's Goal Zero Yeti 6000X for a full comparison review, I took a photo of the Delta Pro next to it for size comparison- Outputs 3,600W continuously only if powered from its battery and not in a 120V UPS pass-through configuration- No vehicle integration kit- Cable to link Delta Pro with additional Smart Batteries is too short, limiting how and where the batteries can be placed- Car Cigarette Port only accepts 96W of input at 12V-- Goal Zero Yeti X and Jackery Explorer series can take 120W (12V @ 10A)- Many configuration options are only available through the EcoFlow smartphone app and not from the Delta Pro itself- Anderson Power Pole (APP) solar part is configured vertically (like Goal Zero, but in reverse)-- Most companies arrange APP horizontally-- Can be remediated by buying an APP extension cable, such as those by iGreely, and re-arranging it- Manual: Not as detailed and as many helpful tips as Goal Zero's- Not an American company- Not waterproof. Keep it away from water splashes, rain, and pool!USAGECONTINUOUS VS PEAK OUTPUTIt is important to understand the difference between Watts and Watt-Hours. How much power is used or produced is measured in Watts, and how much energy a battery can store is calculated in Watt-Hours. See the "Calculations" section below for more details.How much energy a battery can store is measured in Wh (Watt-hours), and how much power is used or produced in W (Watts).- AC Inverter: Converts battery (DC) power into AC-- Delta Pro provides 3,600W continuous output with a 7,200W peak- Peak/Surge (Starting): Nearly every device initially draws extra power to turn on. The highest amount it pulls is the Peak. As long as that number is below 7,200W, it can be STARTED. Because the Delta Pro's capacity is so high, it is difficult to provide examples for devices that start at over 7,200W. So, to illustrate the concept, I will use the Goal Zero Yeti 1000 Core's specs (2,400W peak and 1,200W continuous) as examples.-- Turns on OK (PEAK under 2,400W):--- Freezer starts at 400W (peak), runs at 150W once on--- Coffee maker starts at 1,400W (peak), runs at 800W once on-- Will NOT turn on (PEAK over 2,400W):--- Home AC starts at 4,000W (peak), runs at 1,000W once onMost devices power on at a higher (Peak) wattage than when they are already on (Continuous). Therefore, if its peak exceeds the power station's max, it may not be able to start- Continuous Output (Running): Once devices are on, as long as they keep drawing less than 3,600W total, they will stay ON until the battery runs out-- CONTINUES running (under 3,600W)--- 100W TV + 60W laptop = 160W-- COULD STOP running (over 3,600W)--- Temporary overdrawing beyond 3,600W for a few seconds is okay. A quality BMS will protectively shut down the battery if the surge does not end after a while. Regularly going over for a prolonged time can ruin the battery in the long run--- 300W appliance (500W peak) + 1,000W Home AC (4,000W peak) + 800W Coffee maker (1,400W peak) + 1,200W Miter saw (2,400W peak) + 400W appliance = 3,700W. Probably will stay on for a short period---- Add 1,000W mower (1,400W peak) = 4,700W. Battery will definitely shut downCALCULATIONS - SIZE & TIMEWhat size battery should you get? How long will it power your fridge for? How long will it take to recharge? The below calculations can help answer those questions and are rough ESTIMATES as conditions, battery quality, and age can vary.TIME TO CHARGE BATTERY- Calc: Hours to charge battery = Battery capacity (Wh) / Input Wattage-- Note: As battery approaches 75% full, the input charge will increasingly be slowed down to prevent overcharging- AC Wall: 1,800W @ 2 hrs [3,600 Wh / 1,800W]CHARGE TIME WITH SOLAR- Calc: Hours to charge battery = Battery capacity (Wh) / (Panel Wattage x [0.5 or 0.75])-- In a perfect lab environment, solar panels charge at the listed wattage-- Expect to only receive 50-75% on a good, sunny day (ie. 75W – 113W for a 150W panel), depending on panel's age, component quality, and weather- Two 400W solar panels: as fast as 6 hours [3,600Wh / (2 x 400W x 0.75)]WATTS USED/PRODUCED- Calc: Watts used or produced by device = Voltage x Amperage- Vacuum with 120V @ 9.5A uses 1,140W- Solar panel with 12V @ 10A can produce up to 120WIDEAL BATTERY SIZE- Calc: Battery capacity (Wh) = Watts used by device x Hours needed for / 0.85-- 10-15% of power is lost during power conversion- 45W car fridge needed for 8 hours: Minimum 424Wh power station (45W x 8 / 0.85)How much energy a battery can store is measured in Wh (Watt-hours), and how much power is used or produced in W (Watts).TIME BEFORE BATTERY IS EMPTY- Calc: Hours available for device = Battery capacity (Wh) x 0.85 / Watts used by device-- 10-15% of power is lost during power conversion- 60W laptop with 505Wh battery: Up to 7.2 hours (505Wh x 0.85 / 60W)TIME TO CHARGE DEVICE- Calc: Hours to charge device = Device's battery capacity (Wh) / Input Wattage- 60W laptop with 200Wh battery: Up to 3.4 hrs (200 Wh / 60W)