Expand AC Core: Storage for heat pump and electric vehicle

An additional battery and an additional main unit serve different purposes. More capacity provides energy for a longer duration. Conversely, more available power can support several appliances running at the same time. This distinction is important if you want to use an existing PV system to also supply a heat pump or electric car.

B500: more energy for later

With the SunEnergyXT 500 PRO AC Core, B500 expansion batteries supplement the storage capacity. The modular tower concept can be expanded up to 30 kWh in the 5 kWh class. Additional batteries alone do not increase the output power of the main unit.

An AC Core Set with 10 kWh can therefore provide energy for longer than the 5 kWh version, but it remains a system with a 2,400 W main unit. The decisive factor for capacity is your consumption between two logical charging phases.

Additional main units: an option for more power

SunEnergyXT describes configurations for AC Core with multiple main units and total outputs of 2.4, 4.8, or 7.2 kW, respectively. These figures refer to suitable, designated system configurations. They are not a blanket approval for any existing circuit.

Implementation must be planned by a specialist company based on the house connection, wiring, protection, grid connection requirements, accessories, and the specific manufacturer approval. A larger battery tower is not a substitute for a second main unit. Likewise, a multi-unit configuration is not automatically a three-phase backup power supply for the entire house.

Heat pump: check electrical power and runtime

A heat pump is supplied via the appropriate house installation. The storage system can cover part of its electricity demand; if the available storage power or energy is insufficient, additional electricity is drawn from the grid during normal operation.

Do not confuse the heat output of the heat pump with its electrical power consumption. Check the electrical operating power, potential startup spikes, immersion heater, and household appliances running at the same time. In winter, there is also often less surplus solar energy available while heating demand increases.

For perspective: An electrical device with a constant 2 kW load requires 4 kWh in two hours. This is a simple consumption calculation excluding storage losses or other loads, not a runtime guarantee for a specific heat pump.

Electric car: use your own power via the appropriate wallbox

The car is charged via a suitable charging device, not connected directly to any arbitrary battery terminal. AC Core can contribute energy to the charging process within the home network. However, a single 2.4 kW main unit, for example, does not replace the full supply required by an 11 kW wallbox.

Often, it is worth asking first whether your car can already be charged directly with PV surplus during the day. Every avoided intermediate charge reduces storage losses. For evening hours, stored solar power or appropriately chosen charging windows with a dynamic electricity tariff can be attractive.

Grid operation is not backup power operation

High total power at the house connection, multiple phases, and a supply during a power outage are different planning issues. Accessories, switching, and approvals must match the desired function. A standard AC retrofit does not automatically result in emergency power supply for a heat pump or wallbox.

Which expansion stage do you need?

Start with your daily profile, evening consumption, and the power required simultaneously. Also, collect the model names of your inverter, heat pump, wallbox, and existing energy meter. This helps to distinguish between the need for additional capacity and the necessity of higher multi-unit power.

Send these details to support@wondervolt.de. You can find a starting point in our guide for retrofitting existing PV systems.

Technical basis: SunEnergyXT AC Core and system configurations. The specific design and approval must be verified before ordering a multi-unit system.