ATMOCE MS-7K-U Battery Kit (Single-phase)

It is a battery for the home that connects to the existing distribution board, not to a particular inverter. The difference from ordinary batteries is that, inside, the direct current voltage stays very low — below the threshold considered dangerous — and the conversion into the normal current from the socket is done by the electronics inside the battery's own enclosure. In practice, the risk of an electric arc and of a shock during installation or during a later intervention is much lower than with classic batteries of hundreds of volts. Being coupled on the alternating current side, it can be added on top of an already existing photovoltaic installation, regardless of the inverter brand, or even in a house without panels.

The 7 usable kWh cover, as a guideline, the evening and night consumption of an ordinary home: lighting, fridge, television, kitchen appliances. The discharge power of a maximum of 5 kVA, with a peak of 5 kW, allows several household loads to be supplied at the same time, and charging is done with up to 3.75 kVA. The efficiency measured on the alternating current side is about 90%, meaning that out of 10 kWh put in, approximately 9 are recovered. The 830 x 480 x 195 mm and 73.5 kg enclosure is mounted on the wall or on the floor, and the IP66 protection allows placement outdoors as well, which saves sacrificing a room. The cells are rated for 10,000 full cycles, far beyond what one discharge per day means over the 15 years of product warranty, and maintenance amounts to following the system in the app.

LiFePO4 chemistry, M-ELV architecture with internal DC voltage below 30 V, AC coupling in the 176-276 V range. Continuous charging power maximum 3.75 kVA, continuous discharging power maximum 5 kVA, peak 5 kW, AC round-trip efficiency about 90%. Construction without electrolytic capacitors, integrated relay for protection at the grid interface, monitoring through ATMOCE Cloud and the ATMOZEN app, operating modes self-consumption, time-of-use tariff (TOU), backup and system services. Paralleling up to 126 kWh total capacity. The product code is the same for single-phase and three-phase grids; this kit variant is configured for a single-phase connection, the difference being in the AC wiring and in the metering at the connection point. 15-year product warranty (the documentation in some markets indicates 12 years).

Who it suits

Suitable for a house with a single-phase connection that already has panels and an inverter of any brand and wants to add storage without changing the inverter, or for anyone who wants a battery that can be mounted outdoors.

Terms explained

• AC coupling: The battery connects to the house's alternating current installation, like a large appliance, so it does not depend on the photovoltaic inverter and can be added at any time.
• kVA: A measure of apparent power, close to kW for ordinary household loads; it shows how much the battery can deliver at the same time.
• TOU (time-of-use tariff): The mode in which the battery charges itself when energy is cheap and discharges when it is expensive.

Technical specifications

Recommended applications

• Storage retrofit on an existing single-phase photovoltaic installation, without changing the inverter
• Increasing self-consumption and reducing injection into the public grid at individual houses
• Backup for essential circuits in homes with a single-phase connection
• Optimisation on a time-of-use tariff (charging in the cheap hours, discharging at the price peak)

Warranty

15-year product warranty (the documentation in some markets indicates 12 years)

Technical details

Specifications confirmed from the manufacturer's datasheet

ATMOCE MS-7K-U is an M-ELV (Extra Low Voltage) storage unit with LiFePO4 cells, with 7 kWh of usable energy. The design particularity is that the direct current voltage inside the battery stays below 30 V, the working voltage being raised to AC level by the integrated electronics. This significantly reduces the risk of an electric arc and of electric shock during installation and maintenance, compared with classic HV systems of 200-500 V DC.

The battery is coupled on the alternating current side, so it does not depend on a hybrid inverter: it connects to the existing distribution board and works with photovoltaic installations of any brand or even without panels. The AC working voltage range is 176-276 V. The continuous charging power is a maximum of 3.75 kVA, and the continuous discharging power a maximum of 5 kVA, with a peak of 5 kW. The round-trip efficiency, measured on the AC side, is about 90%.

The enclosure has IP66 protection and can be mounted on the wall or on the floor, dimensions 830 x 480 x 195 mm and 73.5 kg. The design is without electrolytic capacitors, which extends the service life of the electronics; the cells are rated for 10,000 full cycles. The system has an integrated relay for protection at the grid interface and is monitored through ATMOCE Cloud and the ATMOZEN app. The operating modes include self-consumption, time-of-use tariff (TOU), backup and system services towards the grid operator.

The units can be paralleled up to 126 kWh total capacity. This kit variant is configured for a single-phase connection; the MS-7K-U product is the same code for both types of installation, the difference being in the configuration of the AC connection and of the metering at the connection point.