Growatt WIT series modbus documentation.

[Raageri]

@wills106 I go reply from Growatt for my query for new WIT type inverters and i wanted to share it. There is Zip file for documents here []https://growatt-support.com/media/files/be3387f3db485f11ae5243fc71dd7c423d4f2937b7f07b9bf88044b03562db3f/?name=Growatt%20Modbus%20protocols_2024_09.zip

It came also with some information:

Thanks for your email. The Modbus protocol documentations is available for download at the URL below. The file names are numbered to suggest the order in which to read them. It is strongly advised to utilise the VPP Communication Protocol, as it will receive regular updates in the future. If you have any further questions regarding to Modbus, I can help connect you with colleagues who have the required expertise.

[scruysberghs]

Ah, interesting. These might be the key to functionall battery control.

I have tried creating home assistant automation with the controls currently available (time mode with the Load First, Battery First and Grid First options and the power percentage sliders but it just makes no sense currently.
Anyone here with a functioning Growatt modbus battery control script with the current integration?

[scruysberghs]

Where do you get that info? If those parameters are meant for controlling the battery/inverter from an EMS, isn't that is exactly what I am trying to do here?

I have got that information from the installer. When I asked about those registers they replied back that they could not give any information about it. Below is from the VPP document. "No part of this document may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, be it electronic, mechanical, photographic, magnetic or otherwise, without the prior written permission of Shenzhen Growatt New Energy Co., Ltd."

Don't think we are illegally reproducing anything as they publish the document on their website https://growatt-support.com/media/files/be3387f3db485f11ae5243fc71dd7c423d4f2937b7f07b9bf88044b03562db3f/?name=Growatt%20Modbus%20protocols_2024_09.zip

The info has been "around" for a while WouterTuinstra/Homeassistant-Growatt-Local-Modbus#43

[scruysberghs]

With the VPP registers I can do this. Altough 2 weird things :

• "do nothing" now sends 0% power but still discharges the battery ~ @300w
• unlinear link between power percentage and actual power, but that is the same thing I noticed using the number.growatt_modbus_growatt_ems_charging_rate entity

Mine also use 300W without "using" the battery, so that is the selfconsumption. If they sleep they will not use anything I guess.

Still strange, I have never seen this on any other hybrid inverter (Sungrow, Huawei, AlphaEss, SMA, ...). Could it be a setting somewhere? Can you set to to "sleep" and wake it up again without having to restart the inverter/battery?

[flopp999]

Where do you get that info? If those parameters are meant for controlling the battery/inverter from an EMS, isn't that is exactly what I am trying to do here?

I have got that information from the installer. When I asked about those registers they replied back that they could not give any information about it. Below is from the VPP document. "No part of this document may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, be it electronic, mechanical, photographic, magnetic or otherwise, without the prior written permission of Shenzhen Growatt New Energy Co., Ltd."

Don't think we are illegally reproducing anything as they publish the document on their website https://growatt-support.com/media/files/be3387f3db485f11ae5243fc71dd7c423d4f2937b7f07b9bf88044b03562db3f/?name=Growatt%20Modbus%20protocols_2024_09.zip

The info has been "around" for a while WouterTuinstra/Homeassistant-Growatt-Local-Modbus#43

OK, if it is that easy to download, if you have the link without login nobody should not care if you share it.

But I still think those registers are for remote control, but since we can use them, go ahead and do that :)

[scruysberghs]

how often do you change charging rate?

every second, every minute, hour?

I run the script every 30 seconds. But the values do not change that often (and that is why I use the inverters own meter in "follow grid" mode, this allows power follow consumtion near realtime)
I guess using the entities the modbus write only happens when state of the entity changes

[Raageri]

With the VPP registers I can do this. Altough 2 weird things :

• "do nothing" now sends 0% power but still discharges the battery ~ @300w
• unlinear link between power percentage and actual power, but that is the same thing I noticed using the number.growatt_modbus_growatt_ems_charging_rate entity

Mine also use 300W without "using" the battery, so that is the selfconsumption. If they sleep they will not use anything I guess.

Still strange, I have never seen this on any other hybrid inverter (Sungrow, Huawei, AlphaEss, SMA, ...). Could it be a setting somewhere? Can you set to to "sleep" and wake it up again without having to restart the inverter/battery?

Myt Wit goes some kind of "sleep mode" when there isnt any sun. At least cooling goes of.

[flopp999]

#1691 Here someone also mentioned VPP to control the VR instead of using Timers, because of EEPROM.
So, I am thinking about changing or adding VPP Timers to SolaX Integration. What do you think about that?
Is the correct order to activate VPP 30100=1 then set Timers 30412(start), 30413(end),30414(charge discharge)?
Or use 30100=1,30408(minutes),30409(charge discharge)

30408 seems to be a timer countdown while 30412 seems to be Timers that will be stored somewhere, so countdown seems to be more safe to proctect EEPROM

[flopp999]

I’ve done some testing, and here’s what I’ve found:
You set the settings using 30407, 30408, and 30409, then set 30100 = 1.
After that, the settings you entered in 30408 and 30409 will take effect for as many minutes as the value in 30408 — if 30407 is set to 1. Otherwise, it seems to run in LOAD mode.

When in VPP mode and 30407 = 1, if you change 30408, it will follow the value set in 30409 for as many minutes as specified in 30408 — even if you set the same value as before.

It’s not easy to describe this in text, but I hope you understand what I mean.

[brad5505]

This sounds very interesting. I added your VPP Status code for my GEN3 SPH inverter and it seems to work. Would be interested if you could publish your code for 30407, 30408, and 30409
so I could try to control my battery without using eprom codes. Cheers Brad

[brad5505]

Hi,
thanks to infomation from the contributors of discussion, below is the code I have added to my plugin_growatt.py. This is for a GEN3 inverter. As VPP codes maybe more universal, it may work with other Growatt inverters. This is my first attempt at adding code, so may not be completely correct (suggested changes appreciated).

I have also added battery SOH as I thought this would be a useful parameter to monitor over time.

I am controlling battery charge/ discharge on and off via automation to set time, power, remote enable, then VPP enable in this order.
If people have time, could I have any feedback/testing on this and should it be added to plugin_growatt.py.
Cheers Brad

GrowattModbusSelectEntityDescription(
    name = "VPP Status",
    key = "vpp_status",
    register = 30100,
    option_dict = {
            0: "Disabled",
            1: "Enabled", },
    allowedtypes = GEN3,
    entity_category = EntityCategory.DIAGNOSTIC,
    entity_registry_enabled_default = True,
    icon = "mdi:dip-switch",
),
GrowattModbusSelectEntityDescription(
    name = "VPP Remote Control",
    key = "vpp_remote_control",
    register = 30407,
    option_dict = {
            0: "Disabled",
            1: "Enabled", },
    allowedtypes = GEN3,
    entity_category = EntityCategory.DIAGNOSTIC,
    entity_registry_enabled_default = True,
    icon = "mdi:dip-switch",
),
GrowattModbusNumberEntityDescription(
    name = "VPP Time",
    key = "vpp_time",
    register = 30408,
    fmt = "i",
    native_min_value = 0,
    native_max_value = 1440,
    native_step = 5,
    native_unit_of_measurement = UnitOfTime.MINUTES,
    allowedtypes = GEN3,
    entity_category = EntityCategory.DIAGNOSTIC,
    entity_registry_enabled_default = True,
    icon = "mdi:battery-clock",
),
GrowattModbusNumberEntityDescription(
    name = "VPP Power",
    key = "vpp_power",
    register = 30409,
    fmt = "i",
    native_min_value = -100,
    native_max_value = 100,
    native_step = 5,
    native_unit_of_measurement = PERCENTAGE,
    allowedtypes = GEN3,
    entity_category = EntityCategory.DIAGNOSTIC,
    entity_registry_enabled_default = True,
    icon = "mdi:battery-sync",
),
GrowattModbusSensorEntityDescription(
    key = "vpp_status",
    register = 30100,
    scale = { 0: "Disabled",
              1: "Enabled", },
    allowedtypes = GEN3,
    internal = True,
),
GrowattModbusSensorEntityDescription(
    key = "vpp_remote_control",
    register = 30407,
    scale = { 0: "Disabled",
              1: "Enabled", },
    allowedtypes = GEN3,
    internal = True,
),
GrowattModbusSensorEntityDescription(
    key = "vpp_time",
    register = 30408,
    allowedtypes = GEN3,
    scale = 1,
    internal = True,
),
GrowattModbusSensorEntityDescription(
    key = "vpp_power",
    register = 30409,
    unit = REGISTER_S16,
    allowedtypes = GEN3,
    scale = 1,
    internal = True,
),
GrowattModbusSensorEntityDescription(
    name = "Battery SOH",
    key = "battery_soh",
    native_unit_of_measurement = PERCENTAGE,
    device_class = SensorDeviceClass.BATTERY,
    register = 31218,
    register_type = REG_INPUT,
    allowedtypes = GEN3,
    entity_category = EntityCategory.DIAGNOSTIC,
    entity_registry_enabled_default = True,
    icon = "mdi:information",
),

[scruysberghs]

@brad5505 can you share you full growatt plugin file so I can test this?
30407-30409 are indeed the registers I now use with a modbus write in homeassistant (see my script a few posts above) and with 30100 you can indeed (dis/en)able the VPP stuff altogether (if it's off, inverter falls back to max self consumption)

[brad5505]

plugin_growatt (4).py

This is my latest file with the VPP registers
Cheers Brad

[flopp999]

I am working on a new way to detect model. It will use 3 first characters from serial number.
Can you please reply back with your model and 3 first characters in serial number, if you know if it is 1 or 3 phase please add that as X1/X3. If you also know GEN, please add that as well.

Anyone that know how to know what GEN it is, can please reply with that information.
Thanks

MID 15 KTL3-XH : KLN : X3 : GEN4

[flopp999]

don't do it. Someone else tried and got big problems

#1656

[scruysberghs]

do the modbus registers vary so much between models that all this device specific mapping is needed?
In the pdf linked in first post here there is this overview but I seem like the registers I need (battery soc, battery power, solar power, grid power and the vpp controls are the same across all devices):

I must say I have switched from using the esphome modbusbridge method in combination with the solax integration (and home assistant modbus vpp writes) to just adding all the needed registers in the esphome config itself. To me this feels al lot more stable than having to rely on the rtu/tcp conversion on the esp (rtu and tcp timeouts combined seem to be hard to get right)
Also esphome modbus config for numbers and inputs is easier to setup then modbus stuff in home assistant directly.

Gives you this on you esphome device directly :

[flopp999]

do the modbus registers vary so much between models that all this device specific mapping is needed?

Not very much but since the integration works like this I will continue to do it like that, but in a different way.

What you need is not what others need :)

If you detect model you can control what to be shown for the user. Most of the users do not have knowledge how to add/remove/show/hide entities so if the integration is setup as good as possible, you can just add SolaX and all entities will be added for your model.

[scruysberghs]

@flopp999 or anyone here. Have you ever discovered how to make the battery "do nothing". If you use the VPP registers to send 0% (or even -1% or +1%) the battery keeps charging or discharging a couple of 100w . If you turn off remote power control the system goes back to follow load mode and the battery discharges the amount your house is using, even when prices are low.
I'm trying to do this using only the RAM (not eeprom) registers in the document (marked "NOT STORAGE" in the register table) but haven't been able to find the right combination.

[brad5505]

I don’t reduce charging to zero, but on good solar days, I use VPP settings to reduce battery charging to 20% for 4 hours after 9 am to:

1. Reduce the amount of time during the day the battery sits at 100%.
2. Leave headroom in the battery during the solar peak of the day,  so I don’t get "inverter clipping".

[P76E]

Is it needed to set 30100 to 1 or does it accept use of only 30407 + 30474 for example?

[brad5505]

I use all 4 registers. The settings are turned on and off via automation to set time (time period for the battery to charge/ discharge), power(rate of charge/discharge as a percentage - negative value = grid first, positive value = battery first) remote enable, then VPP status to enable in this order.

Below is an example of the action part of the automation to start a grid first sequence:
sequence:

• action: number.set_value
  metadata: {}
  data:
  value: "114"
  target:
  entity_id: number.growatt_inverter_vpp_time
• action: number.set_value
  metadata: {}
  data:
  value: "-80"
  target:
  entity_id: number.growatt_inverter_vpp_power
• action: select.select_option
  data:
  option: Enabled
  target:
  entity_id: select.growatt_inverter_vpp_remote_control
• delay:
  hours: 0
  minutes: 0
  seconds: 1
  milliseconds: 0
• action: select.select_option
  data:
  option: Enabled
  target:
  entity_id: select.growatt_inverter_vpp_status

The battery charge/discharge stops (goes back to load first) after the time period enterd or you can use a second automation to set timers and power to zero, and VPP remote and VPP status to disabled.