AC or DC?
Charging stations are generally available in two types:
- AC (alternating current): For private or semi-public use, typically 11 or 22 kW wallboxes.
- DC (direct current): For commercial use or high-demand charging parks (30–300 kW and above).
Typical use cases:
- Single-family home: 11 kW AC wallbox, optional phase switching (approx. 3.7 kW).
- Multi-family dwellings: Multiple 11 or 22 kW AC wallboxes with load management and optional RFID access.
- Commercial & fleets: Combination of AC chargers for staff and DC chargers for fleet vehicles.
- Public locations: DC fast chargers, especially on highways.
PV Integration: How Surplus Charging Works
With surplus charging, the EV is charged when solar energy is available, reducing grid use. Dynamic PV surplus charging automatically adjusts charging power to available PV output, maximizing self-consumption.
Requirements: Compatible wallbox, compatible inverter, energy manager (e.g. Razo, Clever-PV), smart meter.
Residential: All AC wallboxes in the Krannich portfolio support surplus charging.
Business/DC: Surplus charging is less relevant – focus on delivering performance.
Communication & Control
Modern charging stations rely on multiple protocols and standards:
- OCPP – enables cloud/network services, §14a integration, dynamic tariffs, and load management
- Modbus – for inverter, storage, smart meter, wallbox communication
- LAN/Wi-Fi – for local/remote access
- ISO 15118 – vehicle-to-charger communication, supports bidirectional charging
- RFID – secures chargers, authentication typically via OCPP
Registering & Approving Your Wallbox
In Germany:
- ≤ 11 kW: Registration required, §14a compliance from 4.2 kW
- 11–22 kW: Requires grid operator approval
- > 22 kW / DC: Requires grid compatibility check, detailed planning, protection concept, sometimes a building permit
Similar thresholds apply in Austria, Switzerland, and other markets – check with local grid operators.
Key Charging Station Manufacturers
- Sungrow: Only DC supplier in portfolio. AC version with integrated fault detection, 7 m Type 2 cable.
- Delta AC Max: Compact, low standby use, works without app/software.
- Enphase IQ EV Charger 2: MID-certified meter, AI-based EMS, phase switching.
- Fronius Wattpilot: MID-compliant, dynamic PV surplus charging (1.38–22 kW), Design Award winner.
- GoodWe HCA Series: Quiet wallbox, solar-only or hybrid PV/storage charging possible.
- Huawei Smart Charger: Quick installation, supports phase switching.
- Kostal Enector: Robust (IK10), PV surplus charging, multiple modes.
- Mennekes Amtron Professional: For public/semi-public use, dynamic load management up to 100 stations, external RCD reset.
- SMA eCharger: Fast phase switching, AI-based management, bidirectional ready.
- SolarEdge EVK22C: Controls up to 3 wallboxes, supports surplus charging and low-tariff charging.
- SolaX Smart EV Charger: TLS-encrypted cloud connection, 100% solar charging.