2.5kW - Balcony Set with Backup 5.12kW
€ 1,349.00 (VAT included)
In stock
- SKU: 03100001
- Brand: Marstekenergy
- Category: Inverters
Marstek VENUS-E 3.0 plug-in AC battery: 5.12 kWh LiFePO4, 2.5 kW charge/discharge through a Schuko plug and its own backup socket. Adds storage to any solar system.
How it works: it plugs into an ordinary household socket (Schuko 16 A) and works together with a smart meter in the distribution board (Marstek CT002 or Shelly, not included). When your panels produce more than the house uses, the surplus is not given away to the grid: it is stored in the 5.12 kWh battery. When the house starts drawing from the grid (in the evening and at night), the battery feeds that energy back through the same plug, up to 2.5 kW. During a power cut, its own backup socket keeps powering whatever is plugged into it.
The Marstek VENUS-E 3.0 is a plug-in AC battery: it has no panel inputs, so it doesn't replace your inverter — it adds storage to the system you already have (any inverter brand, microinverters or a balcony kit) without touching its wiring. Its anti-feed-in control complies with the Spanish UNE 217001/217002 standard.
- 5.12 kWh LiFePO4 battery: 51.2 V, 90 % depth of discharge (about 4.6 kWh usable) and more than 6,000 cycles.
- 2.5 kW charge and discharge through the plug: 230 V, 10.9 A; battery-to-AC efficiency above 93.5 %.
- Its own backup socket: 2.5 kVA continuous and 3.5 kVA for 10 s for motor starts. During a grid outage it powers whatever is plugged into it: fridge, router, lights. Whole-home backup with automatic 20 ms switchover requires the MARSTEK SmartBox (not included).
- Expandable: up to 3 units in parallel on single phase (7.5 kW / 15.36 kWh) or 9 on three phase (22.5 kW / 46.08 kWh) with the SmartBox.
- Indoors or outdoors: IP65, −20 to +55 °C, fanless passive cooling. 480 × 153 × 624 mm, 58 kg — fits on a terrace, a balcony or in the garage.
- Control and connectivity: app, WiFi, LAN, Bluetooth and RS485; integration with external energy management systems via Open API and Modbus.
What else you need: the Marstek CT002 meter or a Shelly in the distribution board, so the battery knows when to charge and when to discharge.
Specifications
| Power | 2.5 kW |
|---|---|
| Backup Ready | Yes |
| Phases | Single-phase |
| Battery · bus type | LV (48V) |
| Battery · chemistry | LiFePO4 |
| Subcategory | Mini backup station |
| Battery · capacity | 5.12 kWh |
| EPS backup | 2.5 kW |
| Efficiency | 93.5 % |
| EPS backup · type | Built-in |
| IP rating | IP65 |
| Weight | 58 kg |
| WiFi dongle | Not required |
| Grid power meter | Not included |
| Battery · nominal voltage | 51.2 Volts |
FAQ
Does this system provide real backup power during a grid outage?
Yes, at two levels. The battery has its own backup socket: when the grid goes down it keeps powering whatever is plugged into it, with 2.5 kVA continuous and 3.5 kVA for 10 s. Backing up the whole home with automatic 20 ms switchover additionally requires the MARSTEK SmartBox (not included).
How much energy can the included battery store?
The built-in LiFePO4 battery has a capacity of 5,120 Wh (5.12 kWh) with a 90% depth of discharge, giving you approximately 4.6 kWh of usable energy. The battery is rated for more than 6,000 cycles, translating to over 15 years of daily use.
Is it compatible with my existing solar panels or any PV system?
Yes. It's an AC battery: it connects to a socket, not to the panels, so it works with any PV system — any inverter brand, microinverters or a balcony kit. With the CT002 or Shelly meter it acts as anti-feed-in control, compliant with UNE 217001/217002, so you use 100 % of what your panels produce.
Can I expand the system later if my energy needs grow?
Absolutely. Up to 3 units can be connected in parallel on a single-phase setup, scaling up to 7.5 kW and 15.36 kWh of total capacity using the MARSTEK SmartBox.
How do I monitor and manage the system remotely?
The unit supports LAN, WiFi, Bluetooth, and RS485 connectivity, and integrates with external energy management systems via Open API and Modbus. This allows real-time monitoring of energy production and consumption through a compatible app or platform.
What are the dimensions and weight — will it fit on a small balcony?
The unit measures 480 × 153 × 624 mm and weighs 58 kg, making it compact enough for balconies and small terraces. It carries an IP65 ingress protection rating and operates in temperatures from -20 °C to +55 °C, so outdoor installation is fully supported.
Documents
Shipping across Spain. Delivery in 2-4 business days on the mainland (in-stock products). 14-day return window.