Embrace the Solar Powered Drive
Switch from relying on traditional energy sources to empower your fridge, washing machine, and vacuum cleaner – and even your car – with electricity generated right from your own solar system. This eco-friendly, cost-effective approach to driving is made possible through photovoltaics on the roof and an electric car in the garage.
Homeowners looking to engineer an intelligent, energy-saving household should take note. When connecting power generators and consumers, it's essential to consider some crucial factors, particularly those related to wallboxes.
The Wallbox Conundrum
In the current market, almost every second new solar system is coupled with a wallbox. Ulrich Grimm, Technical Managing Director of wallbox manufacturer Amperfied, reveals that the integration of a wallbox into an overall system – consisting of a PV system and energy management system (EMS) – is one of the most frequently requested features from the private customer market. And, typically, homeowners seek "surplus charging," which allows them to prioritize powering their home's electricity needs with solar energy before charging their car battery with any excess electricity.
An EMS identifies this surplus energy and redirects its flow to the vehicle battery. This intelligent control system can be integrated directly into the wallbox or tethered to the existing solar system at home. To emphasize the importance of this requirement when purchasing a wallbox for surplus charging, research reveals that suitable devices are available between €900 and €1,700. Meanwhile, simpler chargers without EMS capabilities can be purchased for less than €500.
The Need for Phase Switching
To optimize efficiency, phase switching is also a must-have feature. Classic 11kW wallboxes generally use all three phases of the household's current to charge an electric car's battery as swiftly as possible. However, this requires at least a 4.2kW minimum output, which may not always be available via a solar system – especially when sunlight is weak or household energy consumption is sky-high. In such situations, the electric car will fail to charge at all or source its energy from the grid for a fee. This is why single-phase charging (with 1.4kW as the minimum requirement) can prove invaluable.
The Search for Suitable Wallboxes
Those seeking a wallbox for PV surplus charging should conduct thorough research. Directly comparing product names, such as the "Wallbox Connect.solar" from Heidelberg subsidiary Amperfied or the "KeContact P30 PV-Edition" from Keba, can offer a starting point. If the technical data does not provide the necessary crutch, consultations with experts can help.
Top-Performing Wallboxes
Numerous tests conducted by reputable automobile clubs and specialized media can further aid your search. For instance, the ADAC recently tested eight PV wallboxes and found them all to be commendable in various aspects. The Fronius Wattpilot, reportedly, emerged victorious in their comparison.
However, before settling on a wallbox, additional factors should be considered. For example, many models offer distinctive features, such as password-protected access via RFID card, customizable charging modes, smartphone app connectivity, and displays for poor Wi-Fi or mobile phone coverage areas. Price, too, is a significant consideration, especially when evaluating the overall installation cost, including the solar system.
Amortization and Subsidies
For those planning to reap the full benefits of surplus charging, midday, when the sun is shining and household consumption is minimal, might present the most significant savings opportunities. However, commuting vehicles are typically only at home during evenings, which could potentially lead to the misuse of surplus electricity if a stationary energy storage system is not in place. Ultimately, a cost-benefit analysis must be carried out to assess amortization.
Good news for homeowners already owning an electric car and a house – subsidies will be available again next year. The state is planning to grant up to €10,200 towards the acquisition of a box and photovoltaics, so future proofing your plans may be a wise choice.
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