Hello from South London

[marcus]

Our system has been evolving over the last few years

• 2018 - 8x 300W Jenkos
• 2021 - 2x HV2600 v1 batteries and the H1-5.0-E Inverter (6kW) was swapped in

Then last year, after coming across this forum, started thinking about the possibilities of increasing capacity. Bought 2x HV2600 v2 batteries and installed myself, closely followed by BMS V2 and using this fix leaving me with a spare BMS V1...

After a few wrong turns (Core? Supervised?) I got HA working on old laptop running Ubuntu using docker and the Modbus integration (using a 304). Over the Christmas break I got my first automation running, though I've since seen much better ones, just let me know as quite happy to delete that post if it's misleading or noise!

Then earlier this month we went ahead with my "big" upgrade following the build of my garden workshop with a flat roof, adding 12x 430W Canadians. I had specifically asked for a FOXESS string inverter (having read that two hybrids would fight each other) and it was the night before installing it, F5000 brand new in it's a box, looking at the lack of 485A/B connections in the manual and reading "got an answer that the F5000 has no capability to export data" I realised I should have researched this a lot more! Long story short, I told the installers this the next morning, he found a spare H1-3.7-E, we swapped that with the 6kW from the loft, disabled the BMS and installed in the workshop.

The MODBUS integration in HA was brilliant, I just removed the configuration from the integration and re-added the 2 USR-TCP232-304 devices by IP, I had to change the Slave ID on one, and give them "friendly" names but it just asked "Add another" and worked!

Maybe a couple questions around the two inverter set up:

I've got both inverters wired to the same CT sensor at the house consumer unit. I wasn't sure if required for the workshop with BMS disabled but did it anyway.
Might that explain the oscillating values we see for the Load value, I'm assuming that the total load from the grid = house load + workshop load

And on the energy dashboard, I think it looks OK but then I've only got a small sample of data to go on so far, I've added both the workshop and house "Utility Meters" for grid consumption and feed in. I might be doubling up values there as they look fairly similar to each other, but will double check against the usage seen from Octopus in a week or so and let you know.

Great forum, it's been super useful, and agree HA can be addictive! Cheers

[Dave Foster]

Hello,

That's certainly quite the system you have there.

I'm intrigued that you have 2 H series installed and your load graph, does that mean each is powering its own consumer unit so effectively one is in series with the other ?

Depending on how it's actually wired would dictate where the CT clamps go and how many, I would have expected each inverter to have 1 CT clamp, but the bigger inverter to have a second CT clamp fitted so it can monitor the output of the other inverter - that way it would know that any excess solar generated was export and not a negative load which I think is what it is showing - but i'd really need to see a schematic of how it's installed to confirm.

[marcus]

Hi Dave,

does that mean each is powering its own consumer unit so effectively one is in series with the other?

Don't think so. The Workshop (with "big inverter") -> feeds into a consumer unit in the workshop. The supply to/from that consumer unit goes into a 40A MCB breaker on the house consumer unit.
The CT clamp is sitting on "my side" of the meter box, but after the connection from the first PV install.

From what I can tell this is how I'd describe it

interesting you mention a second CT, on Modbus there's "Grid CT" which is giving identical values for both inverters, and "CT2 Meter" neither have anything showing/wired..

Re. the Energy dashboard config, I cross checked the energy import/export values from Octopus and it's looks correct to include the sensors for both inverters. e.g looking at Octopus Export for Sunday (when the sun came out ) it was 4.4kWh and on my Energy dash I see it was -2.1 kWh Feed In Workshop and -2.2 kWh Feed In House, similar for the meters for sensor.house_grid_consumption_energy_total & sensor.workshop_grid_consumption_energy_total - so I'm not double counting but the consumption and feed in seems to be getting split evenly between the two.

[Dave Foster]

Looking at that schematic wiring I think you will get strange load numbers as any generation from the H3.7 (house) will look like negative house load.

The Grid CT sensor you are seeing is exactly what the inverter is seeing and it uses that to work out the house load, but if there is another generation source it will get it wrong (usually in a negative way), you need to let it measure the generation from the H3.7 via it's CT2 input.

Assuming that schematic is correct, i've modified it to show the CT positions to get round the strange load values you are seeing -

The big H5 inverter with the batteries will act as a true Hybrid covering the house load, charging the batteries and exporting as normal, whereas the H3.7 will be acting simply as a solar only inverter (similar to how your thinking started out).

Because the H5 CT clamp will be measuring at the smart meter it will see all of it's generation and the generation of the H3.7 and if when it has CT2 attached it can do the internal maths to show the correct house load - it will still use all available generation to charge it's batteries etc..

[marcus]

Thank you for the explanation. You are absolutely right, when I see generation increase from the workshop the house load goes down, and can even become negative..

One thing I didn't mention, the batteries are still in the loft connected to the H3.7, I was was going to leave them there unless there's a good reason to move them to the workshop?

Assuming I'm leaving there, and understanding the way the CT needs connecting, could I sanity check this:

• the solar only inverter has no CT connections. In fact would I disable the setting under Settings -> Feature -> Meter/CT which is mentioned on the wiring guide?
• the hybrid inverter with batteries needs both the CT Grid and the CT2 to the other generation source, which will be connecting (pins 5&6 on H1) to another CT clamp

so in my case (with more details, and again assuming correct):

If I've got this right it should be quite a simple change, I've already got CAT5 running between the workshop, the consumer unit and up to the loft, so should just be a matter of adding a CT Clamp at the workshop end, re-purposing some twisted pairs and joining that connection for the CT2 return. Ofc chances of getting the +/- right first time may vary

This is extremely helpful, and should improve operation as as you say it will calculate the charge based on the correct house load and generation. Thanks again!

[Dave Foster]

Ok I assumed the H5 with all the panels had the batteries on it, probably the one main reason I would have your batteries on this inverter is that it can charge and discharge at 5kWh whereas if attached to your H3.7 the maximum charge/discharge is 3.7kWh (16A) so basically anything more than a kettle would draw from the grid when there is limited solar generation.

But staying with the H3.7 as battery inverter, the ‘solar only’ inverter would need a CT attached as it won’t startup without it, so you would add the extra CT link shown here -

On the inverter with batteries and second CT clamp you will have to go into settings and enable CT2, your pinouts are correct but go careful in that connector it’s easy to break the existing wires (and sometimes the pins).

[marcus]

Thanks for the heads up on the inverter rating against charging/discharging the battery, I had it in my head that was the power rating for the PV, but now I've moved the batteries back with the H1-5.0 I see the benefit of handling surges such as kettles etc over the H1-3.7

Load now looks as it should, only showing on the H1-5.0, and not including battery charging. The other side effect being I take back what I said about adding BOTH workshop and house consumption/feed-in Utility Meters to the Energy Dashboard. From what I can see it's no longer being split and all recorded against the H1-5.0 Utility Meter (Entity ID select.grid_consumption_workshop).

All the info & help on the CT/CT2 and clamps set up very much appreciated!