EcoFlow Stream Ultra X
(13 reviews)
3.84 kWh of LiFePO4, a built-in hybrid inverter and up to 1200 W on its own outlets: the EcoFlow Stream Ultra X is the flagship of balcony solar storage.
Characteristics
- Capacity: 3.84 kWh (LiFePO4)
- Output: 1200 W (2 AC outlets) + 800 W grid, 2300 W pass-through
- Solar: 4 MPPT, up to 2000 W
- All weather: IP65, self-heating to -4 °F (-20 °C)
- Battery + built-in inverter, microinverter included
Detailed overview: EcoFlow Stream Ultra X 3.84 kWh balcony solar storage system
The EcoFlow Stream Ultra X is the most accomplished model in the Stream range, EcoFlow's balcony solar storage solution. Unlike conventional expansion batteries, which have to connect to a separate hub, it bundles a 3.84 kWh LiFePO4 battery, a hybrid inverter and four MPPT solar inputs into a single box. Its goal: capture the energy from your panels, store it during the day and release it when you consume, instead of feeding it to the grid for free.
On the solar side, it accepts up to 2000 W of panels across its four MPPTs, which optimises output even with partial shading or differing orientations. The stored energy can then be fed back into the home grid at up to 800 W, the usual limit for balcony installations, or delivered straight to its two AC outlets for up to 1200 W (2300 W of connected appliances while the grid is available), a real asset for powering devices during an outage.
Its 3.84 kWh capacity covers a good part of a household's evening needs, and the system is built to last: LiFePO4 cells, a monitoring BMS, an IP65 housing resistant to rain and dust, and a self-heating function that keeps the battery operational down to -4 °F (-20 °C) for year-round outdoor installation.
The Stream Ultra X is fully controlled through the EcoFlow app (Wi-Fi and Bluetooth), which shows generation, consumption and state of charge, and lets you schedule feed-in strategies according to tariffs. At 39 kg and 420 x 294 x 460 mm, it calls for a careful install, but the required microinverter is included. It is today one of the most complete ways to get into balcony solar storage without stacking modules.
Full specifications
Detailed characteristics (EAN: 4895251666565)
Battery
| Technology?Battery chemistry; LiFePO4 lasts far longer and can be fully discharged, gel/AGM is maintenance-free and cheaper. | LiFePO4 (lithium) |
|---|---|
| Energy?Stored energy in watt-hours. | 3840 Wh |
| Delivered energy, measured?Energy that actually leaves the battery and reaches the devices. Always below the stored energy, as conversion costs heat. Taken from our in-depth review. | 3072 Wh |
| Cycle life?Rated number of charge/discharge cycles, at the stated depth of discharge. | 6000 cycles |
| Expandable up to?Maximum capacity reachable with add-on modules. | 23040 Wh |
Power and protection
| Output power?Maximum power delivered (for storages with a 230 V output). | 1200 W |
|---|---|
| Built-in BMS?Battery management system protecting against overcharge, deep discharge, short-circuit and overcurrent (lithium batteries). | Yes |
| Low-temperature protection / heating?Cuts off or heats charging in cold weather to protect the lithium cells. | Yes |
Solar section
| MPPT controllers?Number of built-in MPPT solar controllers (lets you connect panels facing different directions). | 4 |
|---|---|
| Max solar input?Maximum connectable PV power. | 2000 W |
| Micro-inverter?Power of the inverter that feeds energy back into the home grid. | 800 W |
Connectivity
| Bluetooth?Monitoring and settings via an app over Bluetooth. | Yes |
|---|---|
| Wi-Fi?Remote control and updates over Wi-Fi. | Yes |
Durability and format
| Ingress protection?Water and dust resistance (IP rating). | IP65 |
|---|---|
| Weight?Weight of the battery. | 86 lb (39 kg) |
| Dimensions (L × W × H)?Length × width × height, in millimetres. | 16.5 × 11.6 × 18.1 in (420 × 294 × 460 mm) |
Availability and warranty
| Market launch?Date the model first became available on the European market. Useful to place its generation: technology moves fast in this segment, and a device several years old may be at the end of its commercial life. | August 2025 |
|---|---|
| Warranty?Length of the manufacturer's warranty. | 10 years |
Comparison
How does the EcoFlow Stream Ultra X compare with other balcony solar storage systems, through searches like "best balcony solar storage" or "EcoFlow Stream vs Zendure"? Here is how it stacks up against two references: the Zendure SolarFlow (Hyper 2000 + AB2000) and the Anker Solix Solarbank 3.
| Criterion | Stream Ultra X | Zendure SolarFlow | Anker Solarbank 3 |
|---|---|---|---|
| Capacity | 3.84 kWh | 1.92 to 3.84 kWh | 2.7 kWh (expandable) |
| Solar input | 2000 W (4 MPPT) | 1800 W | 1200 W |
| AC output | 1200 W (2300 W pass-through) + 800 W grid | 800 W grid | 800 W grid |
| Built-in inverter | Yes, hybrid | Separate (Hyper 2000) | Microinverter |
| Observed price | ≈ $1758.85 | ≈ $1354.00 | ≈ $1489.40 |
In short, the Stream Ultra X stands out for its deep integration: battery, hybrid inverter, four MPPTs and two AC outlets in a single box, with the highest solar input (2000 W) and the only direct 1200 W AC output in the comparison, on top of the 800 W grid feed-in. The Zendure SolarFlow stays modular and slightly cheaper but needs a separate hub, and the Anker Solarbank 3 bets on simplicity with a more limited solar input. For anyone aiming for maximum self-consumption with a single device, the Stream Ultra X is the most complete proposition.
Related video
Video: EcoFlow STREAM Ultra X Review: Going Off-Grid with a Balcony Solar System - Published on 22/05/2026
Our tester's review: Julien De Jurquet
The Stream Ultra X is the most accomplished balcony storage system to date. Where most systems settle for a battery module wired to a hub, EcoFlow packs everything into one box: 3.84 kWh of LiFePO4 cells, a hybrid inverter, four MPPT controllers and even two AC outlets. In practice, you plug in your panels (up to 2000 W), store the day's surplus and release it in the evening, either fed back into the grid (800 W, within balcony limits) or straight to its outlets at up to 1200 W during an outage (2300 W of connected appliances while the grid is available). The IP65 housing and self-heating down to -4 °F (-20 °C) allow year-round outdoor installation, and the app control is thorough. Two reservations: at 39 kg, plan a solid mount and a two-person install, and its price places it firmly at the premium end of balcony solar. But for anyone who wants to maximise self-consumption without stacking boxes, it is a very convincing proposition.
In-depth review EcoFlow Stream Ultra X: our full review 4.3/5 Read our full review → Efficiency 4.2 Portability and size not measured Weather resistance not measured Output ports not measured Capacity and expansion 4.5 Solar input and MPPT 4.6 Control and smart features 3.9 Installation and compliance 4.4 Build and endurance 4.5 Battery compatibility not measured Safety and protections not measuredFrequently asked questions: EcoFlow Stream Ultra X 3.84 kWh balcony solar storage system
It is a complete system: it packs the 3.84 kWh LiFePO4 battery, a hybrid inverter and four MPPT solar inputs into one box. The microinverter needed for the install is included, so you only need to add panels.
Up to 2000 W of panels, spread across four MPPT controllers. This lets you mix orientations and limit the impact of partial shading on output.
It feeds up to 800 W back into the home grid, the usual balcony-solar limit, and delivers up to 2300 W through its two AC outlets, useful for powering devices directly, especially during a power cut.
Yes. Its housing is IP65 rated against rain and dust, and a self-heating function keeps the battery operational down to -4 °F (-20 °C). Given its 39 kg weight, plan a solid mount and a two-person install.
Yes, like any grid-connected solar installation, though the paperwork depends on where you live: registration in the Marktstammdatenregister in Germany (no separate grid-operator notification needed since the Solarpaket I reform), a declaration to Enedis in France (plus a Consuel safety certificate if wired into a dedicated circuit), a communication to the local distributor under CEI 0-21 in Italy, and registration under the RD 244/2019 self-consumption regime in Spain. Check the current rules where you live before commissioning it.
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