Bms Soltaro Cluster VersionB
The Soltaro Soltaro Cluster VersionB is a lithium iron phosphate (LFP) battery management system designed for multi-rack residential and light-commercial energy storage. It communicates via Modbus RTU over RS485 and requires firmware dated 20191016 or later. This template reads cluster state of charge, DC voltage, current, charge indication, system running state, insulation status, and BMS charge/discharge power limits. It also exposes write registers for cluster start/stop, per-rack enable/disable, insulation alarm thresholds, and EMS address configuration. Use it to keep a complete view of a multi-rack Soltaro cluster from your ModbusCloud portal.
- Protocol
- Modbus RTU
- Connection
- RS485
- Registers
- 29, read and write
- Brand
- Bms
- Last updated
Registers (29)
18 read, 11 write
| Name | Unit | Access | Address (Hidden until you enter your email) | Function (hidden) | Type (hidden) |
|---|---|---|---|---|---|
| reset | Write | ||||
| cluster_start_stop_a | Write | ||||
| rack_1_usage_a | Write | ||||
| rack_2_usage_a | Write | ||||
| rack_3_usage_a | Write | ||||
| rack_4_usage_a | Write | ||||
| rack_5_usage_a | Write | ||||
| cluster_start_stop_b | Read | ||||
| rack_1_usage_b | Read | ||||
| rack_2_usage_b | Read | ||||
| rack_3_usage_b | Read | ||||
| rack_4_usage_b | Read | ||||
| rack_5_usage_b | Read | ||||
| system_insulation_level_1_a | Write | ||||
| system_insulation_level_2_a | Write | ||||
| ems_communication_timeout_a | Write | ||||
| ems_address_a | Write | ||||
| system_insulation_level_1_b | Read | ||||
| system_insulation_level_2_b | Read | ||||
| ems_communication_timeout_b | Read | ||||
| ems_address_b | Read | ||||
| charge_indication | Read | ||||
| current | A | Read | |||
| soc | % | Read | |||
| system_running_state | Read | ||||
| voltage | V | Read | |||
| system_insulation | Read | ||||
| bp_charge_bms | Read | ||||
| bp_discharge_bms | Read |
Loading registers…
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If a device is not in the library yet, we build the template for free as soon as we have the register data.
Use cases
- Monitor cluster state of charge continuously to detect capacity degradation across seasonal cycles.
- Track DC voltage and current together to verify that each charge/discharge event stays within expected operating bounds.
- Alert on unexpected changes to the system running state register to catch fault conditions before they cause downtime.
- Compare BMS charge and discharge power limits over time to verify the battery is not silently throttling available capacity.
- Verify per-rack usage states after maintenance to confirm all enabled racks return to active status as expected.
Installation
Confirm the Soltaro BMS firmware date is 20191016 or later using the BMS Monitor software connected via USB-RS485; update if needed before proceeding.
Connect the ModbusCloud Gateway to the RS485 bus of the master battery unit using a shielded twisted-pair cable on the A/B terminals, with a 120-ohm termination resistor at each bus end.
In the ModbusCloud portal, add a new device, import the Bms Soltaro Cluster VersionB template, and set the Modbus unit ID to match the EMS address configured on the BMS (default is typically 1 for the master).
Spot-check the soc register (address 4167) in the live data view and compare the reading to the value shown on the inverter display to confirm correct communication.
Things to watch for
The gateway connects but soc and voltage always read zero. Why?
Verify the Modbus unit ID in the portal matches the EMS address set on the BMS (register 4131). A mismatch causes the BMS to ignore all requests silently. Also confirm the firmware date is 20191016 or later, as earlier firmware does not expose these registers.
I see Master_Slave_Comm_Fault on the BMS. What causes this?
This fault appears when battery rack addresses are set incorrectly or when the RS485 cable between the master and slave batteries is broken or not fully seated. Check that master address is 0, and slave rack addresses are 1, 2, 3, and so on sequentially. Restart the system after correcting addresses.
Values look correct but then go stale or disappear periodically. What now?
The ems_communication_timeout register (4130) defines how long the BMS waits for a poll before entering a timeout state. If the ModbusCloud Gateway poll interval exceeds this timeout, the BMS may suspend responses. Increase the timeout value via register 4130 or reduce the gateway poll interval.
Is it safe to write to the cluster start/stop or rack usage registers remotely?
Use write registers with caution. Writing to cluster_start_stop_a (4119) or any rack_X_usage_a register can interrupt active charge or discharge cycles and may trip BMS protection limits. Always confirm the system is in a safe idle state before issuing write commands, and consult the Soltaro installation documentation before using the reset register (4100) in production.
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