EcoFlow STREAM Ultra X 3.84 kWh

Cost

Price

£1,299

Price per kWh The unit on its own, divided by its capacity. No installation is included.

£338

See it at EcoFlow

Battery

Battery chemistry LFP packs tolerate regular charging to 100%; NMC packs are usually happier kept below it.

LFP

Usable capacity What you can actually take out, which is less than the figure on the box.

3.84 kWh

Continuous output 1,200 W out of its own socket. Tied to the grid it is held to 800 W, which is the figure that matters for a plug-in installation.

1.2 kW

Warranted cycles EcoFlow warrants 70% of the original capacity after 6,000 full cycles.

6,000 cycles

Capacity at end of warranty What the maker guarantees is left after the warranty period.

70 %

Can be added to Whether you can bolt on more capacity later.

Yes

Expands to The most one stack grows to once the extra battery modules are bolted on.

11.52 kWh

Solar input Four MPPTs, 500 W each.

2 kW

Smart meter EcoFlow's own, or a Shelly Pro 3EM: EcoFlow and Shelly sell a co-branded one for the STREAM range. It does not work with the older PowerStream.

Its own or Shelly

Home Assistant EcoFlow publishes a developer API but no integration of its own. The community ones run on that API, so it takes an access key from EcoFlow's developer portal and a round trip through EcoFlow's servers. Nothing here is local.

Community, cloud

UPS switchover The manual says the switch may take up to three seconds, and that it is not a UPS. Three hundred times the Anker: a fridge will not care, anything with a processor in it will have restarted.

3,000 ms

Operating temperature EcoFlow derates the output above 35 °C and the charge below 0 °C.

-20 °C to 55 °C

AC sockets Three-pin sockets on the unit itself, which is what you can run through a power cut without an electrician wiring anything to the house.

2

Bypass output 1,200 W out of the battery and 1,100 W through from the grid. This is the 2,300 W EcoFlow advertises, and it is not what the battery can do on its own.

2.3 kW

Charging

Weather rating The IP rating: the first digit is how well it keeps dust out, the second water. Below IP65 it wants to be indoors. Ranked as the higher number, though strictly a 7 is an immersion test where a 6 is a jets test, so one does not always include the other.

IP65

Warranty

10 years

Ethernet port None. EcoFlow wants it on wifi: without that, the app gives you neither remote control nor history.

No

Wi-Fi

Yes

Bluetooth

Yes

Dimensions

Length

294 mm

Width EcoFlow lists 420 by 294 by 460 mm without saying which is which. Recorded width, depth then height, which is the way round the unit stands.

420 mm

Height

460 mm

Weight Empty

38.8 kg

Tech

App

Yes