Sungrow SG15/17/20RT-P2

Three-phase PV string inverter

The SG15RT-P2, SG17RT-P2 and SG20RT-P2 have two MPPTs and a documented Modbus RTU monitoring path. Protocol V1.1.80 lists their exact device codes and FC04 power registers. Use COM2 A1/B1 with one serial master; the Ver16 manual excludes simultaneous use with COM1 WiNet. A2/B2 remains assigned to the export-control meter.

Sungrow SG15/17/20RT-P2 three-phase PV inverter
  • Modbus RTU

Three-phase PV string inverter

Compatibility

Compatible through Modbus RTU

Sungrow protocol V1.1.80 lists the exact SG15RT-P2, SG17RT-P2 and SG20RT-P2 codes and FC04 running-information registers. The Ver16 manual provides COM2 A1/B1 for external RS-485 communication.

SG15RT-P2, SG17RT-P2 and SG20RT-P2 only. Confirm the full nameplate, firmware, regional grid code, fitted WiNet module, logger and meter. COM2 A1/B1 cannot be used simultaneously with the documented COM1 WiNet setup. Older RT models without -P2 and SG15/20/25CX-P2 are different products.

Connect it with

When COM1 WiNet is not in use and the A1/B1 bus has one designated master

  • Modbus
  • Edge
  • Platforms
Three-phase PV string inverter
Interface
Gateway
Edge
Output
SG15/17/20RT-P2SG15/17/20RT-P2 COM2 A1/B1
Isolated serial interfaceApproved RS-485-to-host adapter
ZGW-20 GatewayHosts Edge locally
EpiSensor EdgeModbus client + register map
Customer platformMQTT · API · files
Modbus RTU · RS-485
Isolated serial
Runs locally
Optional onward data
Use COM2 A1/B1 for the monitoring bus. Preserve A2/B2 for the feed-in meter and keep A3/B3 reserved. The manual excludes simultaneous COM1 WiNet and A1/B1 use; retain the existing plant monitoring arrangement or agree a single-master alternative before connecting Edge. The customer-platform output is optional; Edge remains the local system of record.

Models

Download
ModelsInterfaceRoute into Edge
SG15RT-P2, SG17RT-P2 and SG20RT-P2COM2 RS485-1 A1/B1 for external-device or inverter daisy-chain communication; meter A2/B2 is a different pairUse the V1.1.80 FC04 read map on COM2 A1/B1. Identify the existing WiNet/logger arrangement first because COM1 WiNet and this monitoring bus cannot operate simultaneously.
SG3.0-20RT without -P2The shared Ver16 manual covers these older RT models too, but distinguishes their WiNet-S2 accessory from the P2 WiNet-S arrangementDo not infer that connector or firmware assumptions from the non-P2 models apply to an installed P2 unit.

Specifications

The exact-family V2 datasheet names SG15RT-P2, SG17RT-P2 and SG20RT-P2 with 15, 17 and 20 kW rated AC output, two MPPTs, two strings per MPPT and 22 kg enclosure weight. The newer Ver16 manual is the source for regional apparent-power limits and the COM connector roles. A shared housing does not make non-P2 or CX-P2 guides interchangeable.12

Exact models
SG15RT-P2, SG17RT-P2 and SG20RT-P212
Rated AC output
15, 17 and 20 kW respectively12
PV inputs
Two MPPTs; two strings per MPPT; 1100 V maximum PV input2
PV input current
64 A total, 32 A per MPPT; 80 A maximum short-circuit current total2
Regional AC maximum
15/17/20 kVA for AU, BE and DE; 16.5/18.7/22 kVA for other manual configurations1
COM2 monitoring pair
RS485-1 A1/B1 for inverter daisy chain or external device; not simultaneous with COM1 WiNet1
COM2 meter pair
A2/B2 for feed-in power meter; A3/B3 reserved1
RS-485 chain boundary
No more than five inverters at one point of connection; shielded twisted pair, up to 10 m between devices1
Enclosure
370 × 480 × 195 mm, 22 kg, IP652

Interface

Documented measurements and integration boundaries for SG15/17/20RT-P2.

  • COM2 A1/B1 is the documented RS-485 daisy-chain pair. The manual limits a chain at one point of connection to five inverters and specifies shielded twisted pair with no more than 10 m between devices; a logger's own limits still need checking.
  • COM2 A2/B2 is assigned to the feed-in power meter and A3/B3 is reserved. The meter detects current direction and magnitude; Sungrow says its data may not be used for billing. Neither pair is a spare third-party telemetry port.
  • For a first read, identify the model at wire address 4999, then read active power at 5030, two registers, low word first S32 in W. Compare with the inverter display before adding points.
  • Regional AC apparent-power limits differ. The Ver16 manual gives 15/17/20 kVA maximum for AU, BE and DE, versus 16.5/18.7/22 kVA in other listed configurations. Verify the nameplate and grid setting before sizing or comparing output.
  • DRM and emergency-stop terminals are control and safety functions. This guide does not authorize inverter write commands, export-limit changes or demand-response actuation.

Assessment

Sungrow protocol V1.1.80 lists the exact SG15RT-P2, SG17RT-P2 and SG20RT-P2 codes and FC04 running-information registers. The Ver16 manual provides COM2 A1/B1 for external RS-485 communication.

InteroperabilitySupported with conditions
The exact models and read map are documented. COM1 WiNet and COM2 A1/B1 cannot operate simultaneously; use one designated serial master.14
AccuracyLimited
The protocol defines power scaling and invalid values. Inverter output and the separate grid meter measure different electrical boundaries; neither this read example nor the app establishes a revenue-meter accuracy class.124
SecurityNot yet assessed
The manual describes communication wiring but does not establish authentication or encryption for an independent RS-485 client.1
ReliabilityNot yet assessed
Online monitoring is advertised, but no third-party polling availability or historical backfill guarantee is established.12
RuggednessSupported with conditions
The datasheet specifies IP65, C5 anti-corrosion and the ambient range. Suitability still depends on the exact site installation and regional derating.12
ScalabilityLimited
The manual permits at most five daisy-chained inverters at one point of connection and 10 m between devices; an external polling capacity is not documented.1
LifecycleSupported with conditions
Sungrow publishes an exact-family datasheet and a later Ver16 manual. Keep the installed firmware, accessory and grid-code revision with the integration record.123

Setup

Identify SG15/17/20RT-P2 before reading power

These are synthetic request and data examples, not measurements from a commissioned inverter. Include the actual slave address and a CRC-checked response frame at the site.

Identity request
FC04, wire address 4999 (0x1387), quantity 1. Device codes: SG15RT-P2 0x2445, SG17RT-P2 0x2446, SG20RT-P2 0x2447. Compare the nameplate.
Power request
FC04, wire address 5030 (0x13A6), quantity 2. This selects documented registers 5031–5032.
Synthetic power data
0x4E20 followed by 0x0000 combines low word first to 0x00004E20, or 20000 W. This is a synthetic 20 kW example.
Unavailable value
The signed 32-bit sentinel 0x7FFFFFFF indicates unavailable data; do not chart it as output.
Acceptance boundary
Confirm type, function, byte count, unit, word order, CRC and a live reference before adding further points.

Acceptance: A checked read establishes one monitoring path. It does not authorise power commands, protection changes or market dispatch.

  1. Identify the installation

    Read the complete installed nameplate and firmware. Confirm SG15RT-P2, SG17RT-P2 or SG20RT-P2, the country setting, existing meter, COM1 WiNet module and any logger before choosing a telemetry path.

  2. Check the electrical limits

    Trace COM2 wiring: A1/B1 is the inverter communication pair, A2/B2 belongs to the feed-in meter and A3/B3 is reserved. Do not move the meter or use the reserved pair for a monitoring client.

  3. Configure the monitoring path

    If COM1 WiNet is fitted, preserve the manufacturer's exclusion of simultaneous WiNet and A1/B1 daisy-chain communication. Agree any change with the plant owner and Sungrow installer before altering network or serial wiring.

  4. Preserve assigned buses

    Use the published V1.1.80 map as the starting point. Read FC04 at wire address 4999, one register, and match type 0x2445, 0x2446 or 0x2447 to the installed model. Then read active power at 5030, two registers, low word first S32 in W.

  5. Read the first points

    Compare a fresh power read with the inverter display, then add points with the same documented decoder. Failed polls remain missing rather than zero. A separate grid meter measures the connection point, not this inverter’s output alone.

  6. Compare live values

    Keep grid-code, export-limit, power-factor, DRM, emergency-stop, start/stop and firmware operations under the authorized plant controls. A VPP dispatch route needs a separate control and acceptance design.

Sources

  1. SG3.0-20RT and SG5.0-20RT-P2 user manual, Ver16, October 2025 (opens in a new tab) (PDF) Sungrow
  2. SG15/17/20RT-P2 datasheet, V2 (opens in a new tab) (PDF) Sungrow
  3. SG15/17/20RT-P2 official product page (opens in a new tab) Sungrow
  4. Communication Protocol of Residential & Commercial PV Grid-Connected Inverters V1.1.80 (opens in a new tab) (PDF) Sungrow

Further reading

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