The gateway connects but all register values show zero or error.

Confirm the unit ID in the portal matches the EMS address configured on the Soltaro BMS. Also verify the baud rate in the Gateway settings matches the value stored in the ems_baudrate_b register. A mismatch on either setting causes the BMS to ignore all requests silently.

Why does the charge_indication register always read zero even when the cluster is charging?

The cluster must be in a running state for most status registers to update. Read system_running_state first to confirm the BMS is active. If the cluster is stopped, charge_indication and current will remain at their idle values regardless of inverter activity.

RS485 wiring is connected but I get intermittent timeouts and missing values.

Check that 120-ohm termination resistors are fitted at both ends of the RS485 bus and that the cable shield is grounded at one end only. Soltaro clusters use a daisy-chain topology between racks; a broken cable between any two racks can cause intermittent communication failures on the entire bus.

Is it safe to write to cluster_start_stop or rack usage registers remotely?

Use write registers with caution. Writing cluster_start_stop or any rack_usage register while the system is under load can trigger BMS protection events, interrupt active charge or discharge cycles, and may affect warranty coverage. Always confirm the system is in a safe idle state and consult the Soltaro installation manual before sending write commands remotely.

Free Modbus template: Soltaro Cluster VersionC

Name: Soltaro Cluster VersionC
Brand: Soltaro
SKU: cb01bd3a-9287-4833-ac1d-98120604e950

The Soltaro Cluster VersionC is a multi-rack lithium battery storage system managed by an integrated BMS, designed for residential and commercial energy storage applications. This Modbus RTU template reads operational data including cluster state of charge, DC voltage, current, system running state, charge indication, insulation status, and BMS charge and discharge permission flags. It also reads back the active EMS communication parameters. Write registers let you configure EMS timeout, address, and baud rate, start or stop the cluster, and enable or disable individual racks. Connecting via the ModbusCloud Gateway gives installers a live view of cluster health and BMS-level control across up to five racks.

Registers (26)

17 read / 9 write

Name	Address	Function	Type	Unit	Access
ems_communication_timeout_a EMS communication timeout setting, write to configure timeout value.	4132	FC16	uint16	ms	W
ems_address_a EMS Modbus slave address setting, write to assign address.	4133	FC16	uint16		W
ems_baudrate_a EMS serial baud rate setting, write to configure communication speed.	4134	FC16	uint16		W
ems_communication_timeout_b EMS communication timeout readback, current configured timeout value.	4132	FC03	uint16	ms	R
ems_address_b EMS Modbus slave address readback, currently active address.	4133	FC03	uint16		R
ems_baudrate_b EMS serial baud rate readback, currently active baud rate.	4134	FC03	uint16		R
cluster_start_stop_a Cluster start or stop command, write to start or stop the cluster.	4291	FC16	uint16		W
rack_1_usage_a Rack 1 enable or disable command, write to set rack usage.	4292	FC16	uint16		W
rack_2_usage_a Rack 2 enable or disable command, write to set rack usage.	4293	FC16	uint16		W
rack_3_usage_a Rack 3 enable or disable command, write to set rack usage.	4294	FC16	uint16		W
rack_4_usage_a Rack 4 enable or disable command, write to set rack usage.	4295	FC16	uint16		W
rack_5_usage_a Rack 5 enable or disable command, write to set rack usage.	4296	FC16	uint16		W
cluster_start_stop_b Cluster start or stop state readback, current run state.	4291	FC03	uint16		R
rack_1_usage_b Rack 1 usage state readback, indicates if rack is enabled.	4292	FC03	uint16		R
rack_2_usage_b Rack 2 usage state readback, indicates if rack is enabled.	4293	FC03	uint16		R
rack_3_usage_b Rack 3 usage state readback, indicates if rack is enabled.	4294	FC03	uint16		R
rack_4_usage_b Rack 4 usage state readback, indicates if rack is enabled.	4295	FC03	uint16		R
rack_5_usage_b Rack 5 usage state readback, indicates if rack is enabled.	4296	FC03	uint16		R
charge_indication Charge or discharge direction indicator for the cluster.	4164	FC03	uint16		R
current Cluster DC current, amperes, instantaneous measurement.	4165	FC03	uint16	A	R
original_soc Cluster state of charge reported by the BMS, 0 to 100 percent.	4167	FC03	uint16	%	R
system_running_state Overall system operating state code from the BMS.	4168	FC03	uint16		R
voltage Cluster DC bus voltage, volts, instantaneous measurement.	4169	FC03	uint16	V	R
system_insulation System insulation resistance status reported by the BMS.	4170	FC03	uint16		R
bp_charge_bms BMS charge permission flag, indicates whether charging is allowed.	4174	FC03	uint16		R
bp_discharge_bms BMS discharge permission flag, indicates whether discharging is allowed.	4175	FC03	uint16		R