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.

Free Modbus template: Spelsberg SMART

Name: Spelsberg SMART
Brand: Spelsberg
SKU: ef99e810-61b3-45f3-a6fa-aec4410b34c0

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.

Registers (23)

20 read / 3 write

Name	Address	Function	Type	Unit	Access
charge_point_state Overall charge point state, encoded as a status code.	1000	FC03	uint16		R
evse_state EVSE controller state, indicating readiness or fault condition.	1002	FC03	uint16		R
cable_state Cable connection state, indicating plug presence and lock status.	1004	FC03	uint16		R
current_l1 Instantaneous AC current on phase L1, amperes.	1008	FC03	uint16	A	R
current_l2 Instantaneous AC current on phase L2, amperes.	1010	FC03	uint16	A	R
current_l3 Instantaneous AC current on phase L3, amperes.	1012	FC03	uint16	A	R
active_power Total instantaneous active charging power, watts.	1020	FC03	uint32	W	R
power_total Cumulative total power value, unitless encoded integer.	1022	FC03	uint32		R
active_power_l1 Instantaneous active power on phase L1, watts.	1024	FC03	uint32	W	R
active_power_l2 Instantaneous active power on phase L2, watts.	1028	FC03	uint32	W	R
active_power_l3 Instantaneous active power on phase L3, watts.	1032	FC03	uint32	W	R
active_production_energy Cumulative energy delivered to the vehicle, watt-hours.	1036	FC03	uint32	Wh	R
max_hardware_current Maximum current allowed by hardware configuration, amperes.	1100	FC03	uint16	A	R
min_hardware_current Minimum current allowed by hardware configuration, amperes.	1102	FC03	uint16	A	R
charge_energy_session Energy transferred in the current or last session, encoded value.	1502	FC03	uint16		R
charge_start_time Timestamp when the current charging session started.	1504	FC03	uint32		R
charge_duration_session Elapsed duration of the current charging session.	1508	FC03	uint32		R
charge_stop_time Timestamp when the last charging session ended.	1512	FC03	uint32		R
charge_save_current_limit Saved current limit applied at the start of a session.	2000	FC03	uint16		R
apply_charge_power_limit Setpoint to write maximum allowed charging power, watts.	5000	FC16	uint32	W	W
apply_charge_current_limit Setpoint to write maximum allowed charging current.	5004	FC16	uint16		W
life_bit_a Watchdog heartbeat read register; reflects current life-bit value.	6000	FC03	uint16		R
life_bit_b Watchdog heartbeat write register; EMS must toggle to keep control active.	6000	FC16	uint16		W