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.

[mstormi (Markus Storm)]

@somy

8-9 years to get back investment on battery which doesn’t look like a good investment.

it still IS a positive Return on Investment, isn’t it. Future CO₂ pricing will improve it further, so why not?

[mstormi (Markus Storm)]

@chris4789

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

That’s a tough one to properly automate indeed.
I managed to get the combo to work meanwhile.
You might know I’m selling a commercial HEMS based on openHAB.

We’re looking for Huawei owners to test our implementation including battery charging. Contact me if you’re interested.
You need to be located in Germany and get a discount in return.
.

[somy (mai)]

Well - the battery has 10 years warranty so in worst case it might just break even (in financial terms I’m actually losing money due to FV=PV). In Denmark a 5kwh battery costs 4000eur, if discharge during the most expensive hours I will get back 0,20eur per kWh per day. And I understand it’s not the full 5kwh I can use as the capacity will go down over the years

[mstormi (Markus Storm)]

If warranty already is 10 yrs, lifespan will be much larger.
And Return on Invest is very much non-linear. A single kWh of capacity will do to mitigate spikes.
The savings the first kWh of capacity gets you are a lot higher than those of the fifth or tenth.
Get a smaller battery to boost your RoI.

[somy (mai)]

I don’t think it will last much longer than 10 years. Discharge cycles is rated at 6000, so 2 times a day it will last just about 10 years

[mstormi (Markus Storm)]

That just means capacity and/or speed will decrease below a threshold that’s defined as per warranty rules so savings will become less. But it doesn’t mean it’ll stop working by then.

PV modules also were said to last 20 yrs at most, now it turns out it’s closer to 40.
Batteries in early Teslas also exhibit a longer-than-expected will to survive.

[chrode (pmc)]

I am running a Huawei sun2000 & Luna2000 combo without the dtsu energy meter. Rules for charging / discharging are implemented in openHAB.

Why do I do that?

1. I don’t have any space left to install the dtsu in my switch cabinet + there is 25 meter between the house switch cabinet and the garage switch cabinet where the inverter is installed.
2. I do own another inverter from solar edge with energy meter which is sadly not compatible with the Huawei.

Basically what I do is: take the values from solar edge, calculate if there energy available or needed and send those commands through modbus tcp to Huawei inverter.

Would it be easier to let the Huawei do the math? Yes absolutely, but since I have no space left in the switch cabinet and the modbus values for house consumption and so on are not writable (read only) at Huawei inverter - I took this approach

[chris4789 (Christian)]

Yes, it’s a pity that there is still no real standard protocol.

I stumbled on release notes from a recent firmware update of the sun2000 inverter stating it supports now also sunspec.

I tried the sunspec “three phase inverter” thing without success.
Had someone tried successfully?
The firmware version is V100R001C00SPC165.

[somy (mai)]

Are you able to control Sun2000 and Luna2000 by writing Modbus command to the inverter? I’m considering to have the same combo with the smart meter, but I’d like to control when to charge (vs sell to grid) and discharge myself, is it doable?

[somy (mai)]

Ok if it lasts for that many years I think it’s worthy to consider the battery in my setup.
One thing I learned from the seller that even with battery it can’t run off grid, I was hoping it can provide electricity during emergency cases when there is no power from Grid.
When switching between battery and grid, does it cause any interruption? Like blackout for some seconds? I have some appliances which don’t like power restart…

[mstormi (Markus Storm)]

@somy

When switching between battery and grid, does it cause any interruption?

Very likely so. Can’t tell, maybe anyone of the other readers can. It works with my Sungrow inverter but I don’t own a Huawei and I know uninterrupted power providing is a rare capability among inverters (in fact I don’t know of any other inverter model that can do it, too. Most people with a battery still need to run a UPS.)

[chrode (pmc)]

Yes, doable:

f.e. this modus registers
37001 Charge and Discharge Power
47087 Charge from Grid Function
47100 Forcible Discharge Charge Status