EcoFlow STREAM Ultra X vs Marstek Jupiter C Plus
Technical comparison · All-in-one
Same declared limits: 800 VA feed-in, four MPPT trackers and a 10-year warranty. The choice is between EcoFlow's expandability and grid features and Marstek's Modbus control. All figures are declared by the manufacturers.
| Parameter | ||
|---|---|---|
| In brief | ||
| Nominal capacity | 3.84 kWh | 2.56 kWh |
| Cell chemistry | LFP (lithium iron phosphate) | LFP (lithium iron phosphate) |
| Cost per kWh | 468.49 €/kWh | 233.98 €/kWh |
| List price | 1799 € | 599 € |
| Weight | 38.8 kg | 28.45 kg |
| Dimensions (W×D×H) | — | 48 × 32 × 23 cm |
| How long it lasts | ||
| Battery life cycles | 3650 cicli | 3650 cicli |
| The limit that runs out first | anni di garanzia | anni di garanzia |
| Rated cycles | 6000 cicli | 6000 cicli |
| Warranty | 10 anni | 10 anni |
| The numbers | ||
| Cost of stored energy | 0.128 €/kWh | 0.064 €/kWh |
| Energy density | 99 Wh/kg | 90 Wh/kg |
| Identity | ||
| Use tier | F3 — Flat-sized (3–8 kWh) | F2 — Room-sized (1–3 kWh) |
| Price | ||
| Price | ~1000–2200 € | — |
| Category specs | ||
| Depth of discharge | — | 90 % |
| Expandable | Yes | Yes |
| Maximum expanded capacity | 23 kWh | 10.24 kWh |
| Battery voltage | 19.2 V | — |
| Feed-in limit | 800 VA | 800 VA |
| Inverter included | Yes | Yes |
| Maximum solar input | 2000 W | 2400 W |
| MPPT trackers | 4 | 4 |
| Grid charging | Yes | — |
| Maximum charge power | 2.3 kW | — |
| Dynamic tariffs | Built in | — |
| Backup power | EPS (brief interruption) | — |
| Backup output | 1200 W | — |
| Ingress protection | IP65 | IP65 |
| Mounting | Wall mounted | — |
| Minimum temperature | -20 °C | -20 °C |
| Maximum temperature | 55 °C | 60 °C |
| Works without internet | With limitations | — |
| Local control | Local network | Modbus |
| Open protocols | Matter | Modbus RTU |
| Declared standards | CE | VDE-AR-N 4105, EN 50549, CEI 0-21, IEC 62619 |
The differences that matter
- Capacity: 3.84 vs 2.56 kWh, expandable to 23 vs 10.24 kWh → how much room you have to grow.
- Solar input: 2000 vs 2400 W, same 800 VA feed-in limit → the Marstek takes 400 W more panels under the same feed-in limit.
- Grid charging at 2.3 kW and 1200 W emergency supply (EcoFlow) → they matter if you want to charge on time-of-use tariffs or keep power in a blackout.
- Control: Matter on the local network vs Modbus RTU → decides which automation system it fits into.
Which one to choose
Choose EcoFlow STREAM Ultra X if…
you want to start at 3.84 kWh and grow to 23 kWh, charge from the grid at up to 2.3 kW with native handling of time-of-use tariffs, and have 1200 W in a blackout (EPS, with a brief gap). You accept 38.8 kg on the wall, control over the local network and Matter, and reduced operation without internet.
Choose Marstek Jupiter C Plus if…
you connect up to 2400 W of panels (against 2000 W) and fold the storage into an automation system over Modbus RTU. It holds 2.56 kWh, expandable to 10.24 kWh, weighs 28.45 kg and lists the grid standards VDE-AR-N 4105, EN 50549 and CEI 0-21.
Where to buy
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