Marstek MARSTEK Venus E 4.0

Name: MARSTEK Venus E 4.0
Brand: Marstek
Author: JouleSpecs

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Data from official source

Sheet curated by JouleSpecs — We check every spec sheet against the manufacturer's own documentation: each value carries its source and the date we read it. Published Sept. 22, 2026 · Last updated Oct. 6, 2026 · Data verified Sept. 22, 2026

MARSTEK Venus E 4.0 is a plug-in storage unit with no inputs for panels: it charges from the home grid and returns AC current from the same port. It suits anyone who already has a solar system and loses the midday sun, or anyone on an hourly tariff who wants to buy at night what they consume during the day. In base mode it feeds in within the threshold for plug-in systems; a more aggressive mode goes beyond that, and installation stops being a simple plug-and-go.

It has a separate backup outlet that handles several appliances together during a blackout. Several units go in parallel, and the ambient temperature range runs from −20 to +60 °C. It withstands rain and dust, and is controlled over Bluetooth, Wi-Fi, a network cable and a serial port, besides the app.

Anyone with panels to attach directly to the battery should look at a model with its own solar input.

01 · Verified data

Technical specifications

Cell chemistry LFP (lithium iron phosphate)

Feed-in limit 800 VA

Round-trip efficiency 90 %

Standby consumption Marstek does not state it.

where we looked

Parameter	Value	Source
Dimensions	43 × 19.1 × 52 cm (16.9 × 7.5 × 20.5 in)	manufacturer website
Weight	47.2 kg (104.1 lb)	manufacturer website
Nominal capacity	5.024 kWh	Declared by the brand
Depth of discharge	88 %	Declared by the brand
Cell chemistry	LFP (lithium iron phosphate)	Declared by the brand
Expandable	Yes	Declared by the brand
Maximum expanded capacity	15 kWh	Declared by the brand
Battery voltage	16 V	Declared by the brand
Feed-in limit	800 VA	Declared by the brand
Grid charging	Yes	Declared by the brand
Maximum charge power	3 kW	Declared by the brand
Backup power	EPS (brief interruption)	Declared by the brand
Backup output	3000 W	Declared by the brand
Rated cycles	10000 cicli	Declared by the brand
Round-trip efficiency	90 %	Declared by the brand
Ingress protection	IP65	Declared by the brand
Minimum temperature	-20 °C	Declared by the brand
Maximum temperature	60 °C	Declared by the brand
Cell supplier	—	Not declared
Inverter included	—	Not declared
Maximum solar input	—	Not declared
MPPT trackers	—	Not declared
Dynamic tariffs	—	Not declared
Switchover time	—	Not declared
Capacity at end of cycle life	—	Not declared
Warranty	—	Not declared
Guaranteed throughput	—	Not declared
Guaranteed remaining capacity	—	Not declared
Standby consumption	—	Not declared
Mounting	—	Not declared
Cell heating	—	Not declared
Noise level	—	Not declared
Works without internet	—	Not declared
Local control	—	Not declared
Open protocols	—	Not declared
Home Assistant integration	—	Not declared
Where the data is hosted	—	Not declared
Remote updates	—	Not declared
App required for setup	—	Not declared
Declared standards	—	Not declared
Battery passport	—	Not declared
Carbon footprint	—	Not declared
Recycled content	—	Not declared
Official list price	—	Not declared

Which documents this page rests on

MARSTEK VENUS-4.0 42 rows of the table · file hosted on cdn.shopify.com

A manual or a datasheet counts as a source even when the original file is hosted elsewhere: what matters is the document, not the server. Where that happens, it is stated above.

02 · The numbers

What it really costs

Battery life cycles 10000 cycles stated cycles

the manufacturer does not state the warranty: the limit could be shorter than the stated cycles
the manufacturer does not state the guaranteed total energy throughput, which for heavy users is often the limit that runs out first

How we worked it out

stated cycles: 10000

Energy density 106.400 Wh/kg

on nominal capacity: the manufacturer does not state the usable figure, so the true number is lower

How we worked it out

nominal capacity: 5.024
weight: 47.200

These numbers are calculated, not stated: they have no source to cite, they have a formula you can redo. The price used is the manufacturer's list price, which is stable and the same in every country — not a shop's price on the day.

03 · Summary

Pros and cons

In favour

When the power fails, the backup outlet handles a fridge and a router at the same time.
Several units in parallel, with no need to change the one already there.
Ambient operating temperature runs from −20 to +60 °C, with IP65 protection.
The maximum efficiency between battery side and AC side is above 90%.

Worth knowing

It has no solar input of its own: panels go on a separate microinverter.
Feeding in more than the threshold for plug-in systems needs the more aggressive mode, and with it an installation that complies with local rules.
The depth of discharge is 88%: the usable energy stays below the nominal capacity.

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