SolarMax SP Series Inverter (pv)
The SolarMax SP Series is a single-phase string inverter designed for residential photovoltaic installations, covering models from 1000SP to 3000SP. This template connects to the inverter over Modbus TCP and reads two key registers: instantaneous AC output power and cumulative energy yield. Together these two values give you a complete real-time and historical picture of PV generation. With the ModbusCloud Gateway polling the SP Series inverter at regular intervals, installers and building owners can track yield and detect generation losses without any proprietary cloud dependency.
- Protocol
- Modbus TCP
- Connection
- Ethernet, Modbus TCP
- Registers
- 2, read only
- Brand
- SolarMax
- Compatible models
- SE 4/5/6KTL-S1/G2 Inverter · SP Series Inverter
- Last updated
Registers (2)
2 read, 0 write
| Name | Unit | Access | Address (Hidden until you enter your email) | Function (hidden) | Type (hidden) |
|---|---|---|---|---|---|
| power | W | Read | |||
| energy | Wh | Read |
Loading registers…
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Use cases
- Monitor real-time AC output power to verify the inverter is producing at expected levels throughout the day.
- Track cumulative energy yield over time to compare actual versus estimated annual production for a site.
- Alert on a sudden drop in the power register during daylight hours to catch inverter faults or shading events early.
- Report monthly energy totals from the energy register for tenant billing or subsidy documentation.
- Compare power readings across multiple SP Series inverters on the same site to spot underperforming strings.
Installation
Enable Modbus TCP on the SolarMax SP Series inverter through its web interface or the MaxLink App, under the communication or Modbus section, and note the assigned IP address and unit ID.
Connect the inverter to the same local network as the ModbusCloud Gateway using a standard Ethernet connection; confirm the inverter responds on TCP port 502.
In the ModbusCloud portal, add a new gateway, then import the SolarMax SP Series Inverter template and assign the correct unit ID matching the inverter's Modbus slave address.
Spot-check the power register (address 4151) during daylight hours and verify the reading is a plausible watt value; if the figure appears ten times too high, confirm the scale factor of 0.1 is applied by your polling configuration.
Things to watch for
Power values from register 4151 look ten times too high. Why?
The SP Series reports power at register 4151 with a native scale that requires a factor of 0.1 to convert to watts. If your integration applies a scale of 1 instead of 0.1, all power readings will be inflated by a factor of ten. Verify the scaling applied by the ModbusCloud template matches 0.1 for the power register.
The gateway connects but no register values appear in the portal.
Confirm the inverter's Modbus TCP service is active and reachable on port 502. Check that the unit ID in the portal template matches the slave address configured on the inverter exactly. Some SP Series units ship with a non-default unit ID, such as 127, so verify this in the inverter's communication settings or MaxLink App.
Readings disappear overnight or after the inverter powers down at dusk.
The SolarMax SP Series inverter goes into standby when DC input is too low, and its Modbus TCP service may stop responding during this state. This is normal behavior. Configure the ModbusCloud portal to treat connection timeouts outside daylight hours as expected gaps rather than fault alerts.
Energy register 4129 resets unexpectedly after an inverter restart. Is this normal?
The cumulative energy register on some SP Series units may reset to zero after a power cycle if the inverter's internal non-volatile memory has not committed the value. Cross-reference the displayed total on the inverter's LCD or MaxLink App against the portal value after any restart to detect and correct discrepancies in your historical data.
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