The gateway connects but power and energy both read zero. Why?

A zero reading during daylight usually means the inverter is not in grid-connected generation mode, the slave address in the portal does not match the address set on the inverter, or the RS485 A and B wires are swapped. Confirm the inverter display shows active generation, check the unit ID, and verify polarity on the RS485 terminals.

Values appear but they seem far too high or too low. What is wrong?

Growatt input registers use a raw uint32 value that must be divided by the documented scaling factor to obtain engineering units. The template registers do not carry explicit unit labels, so confirm the scaling with the Growatt Modbus RTU Protocol II datasheet for your specific model. Misapplied scaling is the most common cause of out-of-range readings.

Communication fails intermittently or I get CRC errors. How do I fix this?

Growatt's RS485 protocol requires a minimum gap of 850 ms between successive commands. If the ModbusCloud Gateway poll interval is set shorter than this, the inverter will miss requests and return errors. Set the poll interval to at least 1 second. Also verify the cable length and termination resistor, as long or unterminated RS485 runs increase error rates.

The energy register value resets unexpectedly after a power cycle. Is that normal?

The cumulative energy register on Growatt inverters is stored in non-volatile memory, so it should survive a power cycle. If it resets, this may indicate a firmware issue on the inverter or a register address mismatch. Confirm you are polling address 91 with function code 4 and cross-check against the Growatt Modbus RTU Protocol II documentation for your firmware version.

Free Modbus template: Growatt Hybrid Inverter (pv)

The Growatt Hybrid Inverter is a residential and light-commercial PV inverter that combines solar generation with battery storage management. This template reads the two core PV data points over Modbus RTU: instantaneous PV input power at register 1 and cumulative PV energy at register 91. Connecting these registers to the ModbusCloud portal gives installers and asset managers a live view of generation output and a running energy total, directly in the dashboard without additional hardware.

Name	Address	Function	Type	Unit	Access
power Instantaneous PV input power reported by the inverter.	1	FC04	uint32	W	R
energy Cumulative total PV energy generated since installation.	91	FC04	uint32	Wh	R