At the EnerGaïa fair in Montpellier, Marstek took advantage of the very “hands-on” atmosphere of the forum (installers, manufacturers, integrators, engineering firms… in short, the people who ask the tough questions) to officially introduce two new products in its range of solar batteries VENUS: the VENUS G and the VENUS D in AC version. The idea is consistent with the concept presented at IFA 2025, “Plug in. WireLite.”, with a simple promise on paper: storage solutions that are easier to install and capable of integrating with most existing photovoltaic installations.
EnerGaïa: Marstek arrives with a range aimed at “hassle-free” installation
Marstek has clearly positioned EnerGaïa as the showcase for its full range, focusing on compatibility and ease of deployment.
The on-site presentation also provided some context about the brand: founded in 2009, over 400 engineers, more than 1500 employees, 4 factories, and a reported revenue of 524 million euros in 2024. In short, this is not just another startup.
On the support side, the message emphasizes customer service that is reachable 24/7 and responses within ~20 minutes “per question” (it’s ambitious, but that’s the message).
What stands out the most is the strategy: promoting a “residential” range capable of covering multiple use cases, from the plug-and-play battery that optimizes self-consumption to more robust storage aimed at powering a large part of the home, even in case of a power outage.
VENUS G: modular storage from 5 to 30 kWh, AC coupled and designed for the home
The first major announcement: the Marstek VENUS G, a modular AC-coupled battery, rated at 5 kWh per module, expandable up to 30 kWh. Modules stack simply, as we have already seen with Zendure or Anker Solix for example.
The central argument is compatibility with the major families of PV installations (Marstek specifically mentions Enphase and SolarEdge) and the addition “without having to redo everything”.
Regarding power, Marstek highlights a bidirectional inverter of 5 kW, an announced efficiency of > 97 %, and the ability to accommodate up to 7.5 kW in AC PV input (with a “smart control” logic for existing setups).
Another interesting technical point: the “500V V-Boost” technology, presented as individual pack control to limit imbalances between LFP modules.
And then there’s the subject that speaks to everyone (even to those who swear they will “never need it”): backup. Marstek announces automatic switching in less than 10 ms, with an emergency output (EPS) and up to 10 kW peak in this mode.
Finally, on the “on-the-ground” side, the message also emphasizes integration details: IP65, operational range from -20°C to 55°C, and a noise level below 30 dB.
For connectivity, there’s Wi-Fi, Bluetooth, RS-485, and Ethernet, with mention of an open API and possible integrations with third-party EMS (and inevitably, that raises eyebrows for home automation…).
VENUS D in AC version: the plug & play aimed at self-consumption (and dynamic pricing)
The second new product highlighted at EnerGaïa: the VENUS D in AC version. The goal is clear: a “plug & play” battery to maximize the use of solar surplus, without depending on a specific inverter brand.
The announced capacity is 2.56 kWh per unit, expandable up to 15.36 kWh in single phase (up to 138.24 kWh in three-phase!), with a bidirectional power of 2.5 kW.
Where Marstek wants to distinguish itself is in the “control” layer: the brand highlights optimized management by AI, associated with the smart meter CT002, to anticipate household needs, plan charging/discharging, and distribute energy at the “right” time.
In the presentation, dynamic pricing is mentioned as a major lever, with the idea of charging when the price is low and discharging when it is high (the case study mentioned on-site: Tempo / peak hours-off-peak hours, with a need for finer automation on the French side).
On longevity, Marstek sticks to LFP cells, announced to be guaranteed for 10 years and rated for more than 6000 cycles (with a lifespan “up to 15 years” mentioned).
Smartbox: the piece that is often missing for a true “whole-home backup”
One point clearly caught attention during discussions: the “Smartbox”. The idea, as explained, is to transition from a simple backup outlet to a cleaner switch on a dedicated line, so that backup becomes more transparent in case of a power outage (and not just “one has to go plug in a cable”).
The product supports for the VENUS D AC also talk about “Whole-Home Backup in One SmartBox”, with extension scenarios reaching (on paper) up to 46.08 kWh in single-phase and 138.24 kWh in three-phase, in a “cluster” configuration.
Of course, this kind of promise always depends on installation conditions, standards, and actual sizing (power, backed-up circuits, balancing, etc.). But in principle, it’s exactly the missing link that many “consumer” systems leave aside.
Home Automation: Home Assistant, Shelly, and the reality of “it will come in an update”
The subject also naturally shifted to home automation integration, with several discussions around Home Assistant and the meters (Shelly vs CT002). The CT002 is currently the most “plug & play” solution on the Marstek side. While Shelly is also compatible, its use may require more setup depending on the cases.
However, the open API allows integration with Home Assistant, which is already in place by the way on the Venus E3 being tested at home for several weeks.
Materially, the bases seem solid and the price/equipment positioning looks aggressive… but the “magic” of control still relies heavily on the software, and that’s typically the kind of point that makes a difference in daily life (especially for those who like to centralize everything in Home Assistant). Fortunately, Marstek is very attentive to users, and several improvements have already been made to perfect the system, which I will discuss in more detail very soon.
What to remember from Marstek’s announcement at EnerGaïa
With VENUS G, Marstek clearly targets those looking for a high-end modular solution, capable of delivering power and capacities tailored to an entire house, with a very responsive backup promised.
With VENUS D AC, the brand maintains a plug & play approach while beefing up the AC version (2.5 kW) and focusing heavily on optimization through AI, dynamic pricing, and ecosystem (CT002, Smartbox, API, etc.).
And the manufacturer doesn’t plan to stop there, as it already plans to offer solutions for installers, such as the Marstek Mars Plus, or even charging stations for electric vehicles, to optimize solar consumption.
We will discuss this in more detail in upcoming tests!
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