Growatt WIT with GridZeno.

Growatt WIT on the compatibility list, updated 31 October 2026.

• Live overview of solar, consumption and gridAll subscriptions
  Works
• Battery state of chargeAll subscriptions · requires a battery · The battery's capacity is also read directly from the inverter.
  Works
• Stop selling at negative pricesSmart and Pro · Measured: export fell from 2.76 kW to 0 in 16 seconds. Depends on how the meter is set up in the inverter, so we check it together with you.
  Works
• Charge from the grid when power is cheapSmart and Pro · requires a battery · Measured: 5.2 kW from the grid on our own system.
  Works
• Discharge the battery when power is expensivePro · requires a battery · Measured: 4.7 kW on our own system.
  Works

Works: tested and measured on real hardware.

The dongle switches the inverter's operating mode according to the plan and always sets it back afterwards. Everything below is measured on our own system, a WIT 15K-HU with a 16 kWh battery.

Charge from the grid

Battery First with the plan's target as the stop state of charge. When the target is reached, the battery stands idle for the rest of the block. Measured: 5.2 kW from the grid into the battery.

Hold the battery

The IDLE mode: the battery neither charges nor discharges while the house uses solar and grid. Then the energy is there when power becomes expensive.

Sell from the battery

A time-limited command in Growatt's VPP protocol. The dongle renews it while the sale lasts, and removes it afterwards. Measured: 4.7 kW.

Stop selling at negative prices

The inverter's export limit is set quarter by quarter by the selling price. Measured: the sale fell from 2.76 kW to 0 in 16 seconds.

Battery limits

Your lowest and highest charge levels are written to the inverter's own limits, so they apply even when the dongle is switched off, as long as the control is on Automatic. On Manual, the inverter gets its own limits back.

The rest of the time

The inverter's own mode, usually Load First. The dongle saves it before it switches the first time, and sets it back after each block and after a restart.

For the installer: the registers

What the dongle writes over Modbus, if you want to follow along or troubleshoot. Don't change the registers yourself while the control is set to Automatic.

Operating mode

1044, mirrored in 895: 0 is Load First, 1 Battery First and 4 IDLE. 949 turns on charging from the grid.

Stop state of charge

999 (AC Stop Charging SOC).

Ceiling for charging from the grid

905, as a percentage of the inverter's rated power.

Sales

30100 and 30407 turn on the control, 30408 is the duration in minutes, and 30409 is the power as a percentage of the rated power.

State of charge limits

951 is the highest and 952 the lowest.

Export limit

122 is the meter's mode and 123 the limit in 0.1 %. With the inverter's internal meter (mode 4), only 123 is written.

The type code 5603 in holding 30000 and a rated power in 30016 of at most 15 kW. If holding 988 reads 1, it's a WIS, which the dongle never controls as a WIT.

What the dongle allows for

• While the VPP command stands (30100 = 1), register 122 doesn't show the installer's meter mode, and it can lag behind a change. So the dongle reads the export limit's starting point only a minute after its latest write to 30100, and only when two readings 30 seconds apart agree.
• With the inverter's internal meter (mode 4), the plan's sale is the export limit itself. In a meter or CT mode (1-3), the installer's limit is a ceiling that GridZeno only lowers.
• The battery's capacity is read straight from the inverter.

How it differs from its neighbours

• Growatt WIT 17-25K-HU and 4-25K-XHU: The same control and the same port, RS485-IN with pins 7 and 8. A WIT above 15 kW is its own model in GridZeno, WIT above 15 kW, and has its control switched on separately.
• Growatt WIT 50-100K: The large three-phase WIT has its own type code and is connected with wires in a 16-pin connector, not with an RJ45 plug.

From the dongle's firmware and our notes on each inverter, not from the datasheet.

Network cable with RJ45 plug. Approx. 20 minutes. Needs an electrician: the inverter has to be opened.

Port

RS485-IN (CN2)

Pin

A at pin 8 (RS485_3A), B at pin 7 (RS485_3B), GND at pin 2 (GND.S)

Where

In the COM1 communication area together with the other RJ45 ports. The cables are fed in through the cable gland (the PG head). RS485-OUT (CN3) has the same pins and can be used if RS485-IN is taken.

See the full installation guide for Growatt WIT

GridZeno Dongle for Growatt WIT

This one works.

Growatt WIT is the inverter GridZeno has been tested on. Check that your model is under WIT 4-15K-HU, and that a battery is fitted if you want the battery controlled by the electricity price. If it still doesn't suit you, you have 100 days' free return.