The gateway connects but all register values read as zero or null.

Confirm that the unit ID in the ModbusCloud portal matches the slave address configured in the inverter. The Ampere.StoragePro inverter commonly uses unit ID 2, while the Ampere.IQ energy manager uses unit ID 1. A mismatch causes silent zero or empty responses rather than a connection error.

The energy register returns implausible or scrambled 32-bit values.

The energy register is uint32, spanning two consecutive 16-bit Modbus words. If your reading appears byte-swapped or word-swapped, check the word-order setting in the ModbusCloud Gateway configuration. The SAJ H2 protocol uses big-endian byte order, but some firmware builds swap the high and low words. Try toggling the word-order option and re-reading the register to confirm the correct value.

Polling drops out intermittently after adding more monitoring clients.

The Ampere.StoragePro's Modbus TCP server supports only a limited number of simultaneous TCP connections. If the Ampere.IQ box, Home Assistant, and the ModbusCloud Gateway all poll concurrently, the inverter may refuse or drop connections. Reduce polling sources or increase the ModbusCloud Gateway polling interval to avoid saturating the connection limit.

Grid power values look correct at midday but drift oddly overnight.

Assign a static IP address to the inverter. If DHCP reassigns the address after a lease expiry, the Gateway will continue polling the old address and may receive responses from a different device or time out silently. Document the static address and update the portal configuration if you change it.

Free Modbus template: Ampere Ampere.StoragePro (grid)

The Ampere Ampere.StoragePro (grid) is a hybrid solar inverter and battery storage system marketed by Energie Konzepte Deutschland and built on the SAJ H2 Series platform. It combines PV generation, battery charging and discharging, and grid interaction in a single unit for residential and small-commercial installations. This Modbus TCP template reads the grid-side measurements exposed by the inverter: total grid exchange power, per-phase AC currents on phases A, B, and C, and cumulative grid energy. Connecting these registers to the ModbusCloud Gateway gives installers and building owners a live and historical view of grid import and export without proprietary cloud dependencies.

Name	Address	Function	Type	Unit	Access
power Grid exchange power, signed; positive means import from grid.	16557	FC03	int16	W	R
currents_a AC current on phase A at the grid connection point.	16434	FC03	int16	A	R
currents_b AC current on phase B at the grid connection point.	16441	FC03	int16	A	R
currents_c AC current on phase C at the grid connection point.	16448	FC03	int16	A	R
energy Cumulative energy exchanged with the grid, 32-bit unsigned.	16637	FC03	uint32	Wh	R

Ampere Ampere.StoragePro (grid)

Overview

Use cases

Installation

Things to watch for

Registers (5)

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