Spelsberg SMART
The Spelsberg SMART is an AC electric-vehicle wallbox designed for residential and light-commercial EV charging, supporting up to 11 kW three-phase with a variably adjustable charging current. This Modbus TCP template exposes charge point state, EVSE and cable status, per-phase currents and active power on L1, L2, and L3, cumulative session energy, and hardware current limits. Write registers allow an external energy management system to apply a power or current setpoint in real time, while the life-bit watchdog pair keeps the control link verified. Connecting the Spelsberg SMART to ModbusCloud Gateway gives installers live session data and remote setpoint control in one portal.
- Protocol
- Modbus TCP
- Connection
- Ethernet, Modbus TCP
- Registers
- 23, read and write
- Brand
- Spelsberg
- Last updated
Registers (23)
20 read, 3 write
| Name | Unit | Access | Address (Hidden until you enter your email) | Function (hidden) | Type (hidden) |
|---|---|---|---|---|---|
| charge_point_state | Read | ||||
| evse_state | Read | ||||
| cable_state | Read | ||||
| current_l1 | A | Read | |||
| current_l2 | A | Read | |||
| current_l3 | A | Read | |||
| active_power | W | Read | |||
| power_total | Read | ||||
| active_power_l1 | W | Read | |||
| active_power_l2 | W | Read | |||
| active_power_l3 | W | Read | |||
| active_production_energy | Wh | Read | |||
| max_hardware_current | A | Read | |||
| min_hardware_current | A | Read | |||
| charge_energy_session | Read | ||||
| charge_start_time | Read | ||||
| charge_duration_session | Read | ||||
| charge_stop_time | Read | ||||
| charge_save_current_limit | Read | ||||
| apply_charge_power_limit | W | Write | |||
| apply_charge_current_limit | Write | ||||
| life_bit_a | Read | ||||
| life_bit_b | Write |
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Use cases
- Monitor per-phase currents on L1, L2, and L3 to detect load imbalance across sessions.
- Track cumulative session energy to verify charging totals against MID billing records.
- Alert on unexpected charge point state changes to catch EVSE faults before a driver reports them.
- Apply a power setpoint via apply_charge_power_limit to limit wallbox draw during peak tariff hours.
- Compare hardware current limits against configured setpoints to verify load-management bounds are respected.
Installation
Enable Modbus TCP on the Spelsberg SMART: open the Spelsberg Wallbox App, go to System, Settings, More settings, Expert settings, then select Energy Management System and set the protocol to Modbus TCP.
Connect the wallbox to your LAN via the integrated Ethernet port and confirm it is reachable on the same network segment as the ModbusCloud Gateway.
In the ModbusCloud portal, add a new Gateway, import the Spelsberg SMART template, and set the unit ID and TCP port to match the values configured in the app.
Spot-check the connection by reading the charge_point_state register; a valid numeric status code confirms the Modbus TCP link is active and the template is correctly assigned.
Things to watch for
The gateway connects but charge_point_state always reads zero.
Zero on charge_point_state usually means Modbus TCP is not yet active on the wallbox. Re-open the Spelsberg Wallbox App, navigate to Expert settings, Energy Management System, and confirm the Modbus TCP mode is selected and saved. Transfer settings to the wallbox via NFC or network before retrying.
Per-phase power registers read values but active_power looks wrong.
The active_power register is uint32 and spans two consecutive 16-bit Modbus words. Confirm your Modbus client is reading both words and assembling them big-endian (most significant word first). A single-register read will produce a truncated or garbage value.
Writing apply_charge_current_limit has no effect on charging speed.
The wallbox enforces hardware limits reported in max_hardware_current and min_hardware_current. Any setpoint written outside that range is silently clamped. Also verify the life-bit watchdog is being toggled: if life_bit_b is not written periodically the wallbox may revert to its internal setpoint and ignore external commands.
Is it safe to write setpoints to apply_charge_power_limit during active charging?
Write registers should be used with care. Sending a power limit that is too low can interrupt an active session or cause the vehicle to stop accepting charge. Always write values within the hardware current band and ramp setpoints gradually. Test in a controlled environment before deploying automated setpoint logic in production.
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