Marstek VENUS E Max
A wall-mounted AC-coupled battery with 10 kWh of storage, 3.6 kW of bidirectional power and 3.6 kW of backup, expandable to 30 kWh with the SmartBox.
- Best for big home storage
- AC battery
- 10 kWh
- 3.6 kW output
- Made by Marstek.
- Capacity: 10.048 kWh (314 Ah, 10S) with LiFePO4 cells and more than 10,000 cycles.
- Power: 3.6 kVA bidirectional AC power and 3.6 kVA backup power, with a switchover in under 10 ms.
- Expansion: up to three units in parallel, for 10.8 kW and 30 kWh, using Marstek's SmartBox.
- Rules: whether you can use it as a plug-in battery depends on your country.
Not tested by us
We have not tested the Marstek VENUS E Max. The figures on this page come from the sources listed at the end of the page, checked on 13 November 2026, and we do not show prices. "Best for" is based on what the maker says the product is designed for, not on our own tests.
Key figures
10 kWh
Capacity, up to 30 kWh with three units
3.6 kW
Bidirectional AC power
3.6 kW
Backup power
Specifications
Last checked on 13 November 2026. The grey text under each name explains what the value means. To see it next to other products, compare it in our comparison tool.
| Specification | Value |
|---|---|
| Storage | |
| CapacityHow much energy the battery stores. Bigger means longer runtime or more of your own solar power used later. | 10.048 kWh (314 Ah x 10S), nominal voltage 32 V |
| Battery chemistryLFP (lithium iron phosphate) cells are known for long life and stable behaviour with heat. | Lithium iron phosphate (LiFePO4), 314 Ah cells |
| Depth of dischargeHow much of the battery can be emptied without harming it. 90% means 10% is kept in reserve. | 90% |
| Cycle lifeHow many full charge and discharge cycles the cells are rated for before they hold less than the stated share of their original capacity. | More than 10,000 cycles at 25 °C. The product page adds a lifespan of up to 15 years. |
| ExpansionExtra battery units that add storage to the same system. | Up to three units in single-phase or three-phase parallel connection with the SmartBox, for 10.8 kW and 30 kWh in total |
| Power | |
| AC output, grid-connectedThe lower output allowed when it feeds power into the home's circuits or the grid. | 800 VA or 3.6 kVA rated output (3.48 A or 15.65 A at 230 V). Power factor above 0.99 by default. |
| Backup outputA separate socket that keeps selected devices running when the grid is down. | 3.6 kVA rated and 3.78 kVA peak for 60 seconds, 230 V / 50 Hz, 15.65 A, through a European standard socket |
| Backup switchover (EPS)What happens when the grid fails. EPS means it takes over automatically. | Under 10 ms, according to the product page |
| AC charging inputHow fast it charges from a wall socket or the grid. | 3.6 kVA rated input power (15.65 A) |
| Efficiency and standby useLosses when charging, discharging and doing nothing. | More than 92% maximum efficiency over a battery-to-AC cycle. The display uses a radar sensor to wake and sleep, which Marstek says cuts standby use; the figure is not stated. |
| Solar | |
| Solar inputHow much solar panel power it accepts. A higher figure fills the battery faster on a sunny day. | No solar input is listed. Marstek describes it as AC-coupled, so it stores power from an existing solar system. |
| Grid connectionThe supply type it is built for. Check it matches your home's supply. | AC-coupled through an MST-Grid port, single phase (L/N/PE), 230 V or 220 V, 50 or 60 Hz. Marstek lists Marstek, Shelly and HomeWizard smart meters for anti-feed-in control. |
| Solar and off-grid | |
| Works with solar panelsWhether you can charge it from solar panels. Yes means a built-in solar input or a compatible solar setup; read the detail for the voltage and power limits. | Partly: AC-coupled, so it works with an existing solar system on the AC side; it has no panel input of its own. |
| Off-grid useWhether the maker describes it running with no grid connection at all, for example in a cabin, van or off-grid home. Backup only means it covers power cuts but needs the grid the rest of the time. | Partly: 3.6 kVA backup output through a socket in a power cut; Marstek describes a grid-connected system, not a stand-alone off-grid one. |
| Connection and housing | |
| Dimensions (W × D × H)Check the space before you buy, including room around it for airflow and cables. | 750 × 450 × 210 mm, as listed by Marstek (axis order not stated) |
| WeightMatters for lifting, wall mounting and moving it. | 86 kg |
| Protection ratingIP ratings show protection from dust and water. IP55 and IP65 are rated for outdoor-style exposure; check the installation guidance. | IP65 |
| Operating temperatureThe range it is rated to work in. Cold and heat can reduce performance. | -20 to 60 °C (storage -30 to 85 °C) |
| Noise levelFan noise while working. | Under 30 dB |
| CoolingHow the heat is removed. Natural cooling is silent; air cooling uses a fan. | Natural convection |
| Operating altitudeThe maximum height above sea level it is rated to work at. | Up to 2,000 m |
| DisplayWhether the unit has its own screen showing charge level and power in and out. | LCD with a millimetre-wave radar sensor that wakes it as you approach |
| ConnectivityHow you monitor and control it, usually through an app. | Bluetooth, Wi-Fi, LAN and RS-485; Marstek app and open APIs |
| Warranty | |
| WarrantyThe period the maker covers. Read the terms: conditions and capacity guarantees differ. | 10 years |
Compatible with
What Marstek says this product works with. Anything not listed here is not confirmed.
- Smart meters
- Marstek lists Marstek, Shelly and HomeWizard smart meters for anti-feed-in control.
- Marstek portable EV charger
- Marstek says it works with its own portable EV charger, with solar-first, scheduled and off-peak charging.
- Existing solar systems
- Marstek says the AC coupling lets you add storage without changing your current solar installation.
- Virtual power plants and smart home platforms
- Marstek says it supports VPP aggregation and connects to major smart home platforms through open APIs.
Rules where you live
Rules for plug-in batteries differ by country, and we could not confirm a version or plug for Great Britain. In Great Britain, plug-in solar kits of up to 800 VA have been legal since 27 August 2026, but the rules exclude plug-in batteries.
Check the rules, incentives and tariffs for your own country in our country guides.
Strengths and things to check
Strengths
- 10.048 kWh in a single wall-mounted unit
- 3.6 kW bidirectional power and 3.6 kW backup with under 10 ms switchover
- Expandable to 30 kWh with up to three units
- More than 10,000 cycles, IP65 and a 10-year warranty
- Under 30 dB and a radar-activated display
Worth checking before you buy
- At 86 kg it is a heavy unit for a plug-in product
- Whether it counts as a plug-in product depends on your country: check the rules below
- It has no solar input, so it needs an existing solar system or inverter
- The datasheet lists a 800 VA or 3.6 kVA grid output without saying which applies where
Change log
We record changes to this page here, so you can see when figures such as the warranty were last updated.
- 13 November 2026
- Page published. Warranty at publication: 10 years (Marstek product page).
Where this information comes from
We have not tested the VENUS E Max. Every figure above comes from Marstek's VENUS E Max product page and its datasheet (PDF on Marstek's download centre), last checked on 13 November 2026. The product page's specification tab was empty, so size, weight and electrical values come from the datasheet. A value these sources do not state is shown as not stated.
We do not show prices, because they change often and differ between sellers. We also leave out Marstek's savings figures, which are theoretical values from its own model.
- Manufacturer Marstek VENUS E Max datasheet (PDF, download centre)
- Manufacturer Marstek VENUS E Max product page
Spotted an error?
Tell us through the contact form on our About Us page.
Common questions about Marstek VENUS E Max
Can I use the Marstek VENUS E Max as a plug-in battery in my country?
It depends on local rules. Marstek markets it as a plug-in battery. In Great Britain, plug-in solar kits up to 800 VA are legal since 27 August 2026 but the rules exclude plug-in batteries. Check our country guides.
Does the VENUS E Max have solar panel inputs?
No. Marstek lists no solar input on the datasheet and describes it as AC-coupled, so it works with a solar system you already have.
How much can the VENUS E Max be expanded?
Marstek says up to three units can run in parallel through the SmartBox, for 10.8 kW of power and 30 kWh of storage.
Related guides
How much could a battery save you?
Our calculator uses your own usage and tariff to estimate what a home battery could save, with conservative assumptions.