Reading data from Huawei inverter SUN 2000 (3KTL-10KTL) via modbus TCP and RTU

[DrScr3w (Alex)]

@somy

Would like to ask if I have both SUN2000 and LUNA2000, do I need 2 ModBus connections to read both from the inverter and battery, or is it enough just connect to SUN2000?
As I understand SUN2000 comes with the WiFi dongle however I plan to install it outdoor, is there any possibility to connect it via Ethernet for ModBus?
Many thanks!

A connection to the inverter (dongle) is sufficient to read out all devices on the ModBus, such as the battery and SmartMeter.

[chris4789 (Christian)]

@somy

any possibility to connect it via Ethernet for ModBus?

The dongle has also a RJ45 jack, so no problem.

[somy (mai)]

Thank you both!

[somy (mai)]

Hello again, my provider said I also need Huawei DTSU666-H 100A smart power meter for battery. Anybody know what it is and is it possible to integrate to OH?
Can the smart power meter provide real time data about current production and consumption?

[chris4789 (Christian)]

Yes the DTSU is neccessary, otherwise you could load battery from grid which makes absolutely no sense.
It is of course connected with the inverter which controls then loading of battery.
It is connected by a simple modbus wire pair, not by ethernet.

[somy (mai)]

Hi Christian,

Thank you for your reply! Sorry I have some follow up questions:
Does it provide realtime data on consumption and production?
If I connect Modbus TCP to sun2000 do I get the realtime data or does it require a separate connection to the smart meter?
I don’t quite understand that the battery can be charged by grid without the smart meter, can you elaborate on that?
My end goal is to automate in OH to decide when to charge/discharge battery, and when to sell to grid vs charging battery. I’m not sure if it’s possible to implement with Modbus? I read some post here that writing to the register doesn’t work, can we only read from Huawei?
Many thanks in advance!

[chris4789 (Christian)]

Hi Mai,
Do not sorry, I was in the same situation last year and happy to get some more information here and there, although I have no battery but a EV which behaves quite the same.

@somy

If I connect Modbus TCP to sun2000 do I get the realtime data or does it require a separate connection to the smart meter?

Battery and DTSU are connected with the inverter, so you get consumption and production values via modbus, but modbus is no real time protocol so there are some fluctuations.

@somy

I don’t quite understand that the battery can be charged by grid without the smart meter, can you elaborate on that?

The inverter does not know the consumption of your house, so it can either load all into the battery or to the grid, or maybe a defined percentage but never the exact PV excess.
The DTSU measures the balance of the three phases and reports to the inverter by modbus.

@somy

My end goal is to automate in OH to decide when to charge/discharge battery, and when to sell to grid vs charging battery.

I have an hourly based tariff which is for me much too hard to automate in combination with PV excess.

I have also no knowledge about writing values by modbus so cannot help here unfortunately.

[somy (mai)]

Thank you for the help, very much appreciated!
I might also skip the battery for now - my calculation with previous years el price shows it will take 8-9 years to get back investment on battery which doesn’t look like a good investment.