Support for 3 x inverters

I am researching a potential system with 3 inverters, and wanted to check what experiences anyone has had with this or similar systems.

1/ Existing 3kWp solar PV with inverter + FIT.
2/ New 3kWp solar PV with GE hybrid inverter, no battery as loft mounted and a/c wiring already present.
3/ New 3kW a/c coupled GE inverter with battery as on ground floor in garage near the main CU.

A few questions come to light to me, but I am sure there are others.

a/ I presume the new solar needs a GE hybrid inverter in order to have the required DC input capability, but will it operate correctly with no battery connected?
b/ Would 5 x EM115 meters be required?
1-FIT a/c, 2-AC-a/c, 3-AC-Grid wired to the a/c coupled inverter
4-Hybrid a/c, 5-Hybrid-Grid wired to the hybrid inverter.
c/ Would all the instantaneous power and historical energy values be visible through 1 user interface, or would each system have to be interrogated separately?

Any tips would be appreciated.

You do not have to have the GE Hybrid inverter for your second PV, any brand inverter will work fine. I am about to add a Solis for my new array. So might be a bit cheaper there.

The AC3 can be fed from both PV's and your installer will add all the required meters. I currently run dual PV and an AC3.

One delay you will have is the G99 application as your total possible output to the grid will be 9Kw

THALL .
Thanks, I did understand that another brand of inverter could be used, it is just I was trying to avoid having to logon to 3 different systems to have visibility of the status of each, for things like PV string voltage and current for assessing the effects of shading at certain times of day.

So do you have live power values and trend charts of energy for each of the PV, the AC3 and the grid all visible simultaneously? Or is the PV totalled together?

Is the DNO application for anything over 3.68 kW/16A, or are there other higher limits?

Simon_C I believe @hoggy has a 5kW limit looking at his online metrics and others may have higher values too. I suspect the 3.68kW/16A is the minimum that the DNO is obliged to allow, the same as any supplier with more than (I think 150,000 customers) has to offer a SEG tariff to anybody asking. On the assumption that you will be limited to 3.68kW and that your new plant can be configured to limit total output to that value, it could be low risk to commit to the design and get the order in. If, when the G99 comes back, your limit is higher, happy days. I waited for the G99, was limited to 3.68kW anyway but delayed the contract by about four weeks.

Tim is correct in that I'm on G99 with an export limit of 5kW on a Hybrid 5. (In hindsight I should have asked for more but never mind)
Mine is a bit Frankenstein now though with battery only discharge rate up at 5kW - albeit it still skirts under the G99 Limit I was given.

G98 is =<3.68kW Total export capacity from the entire house (not per inverter). DNO can't reject it & notify after install is fine. This may limit you with clipping of power at times though depending on your array size.

Things get a bit more blurry above that and I'm probably not the best to comment as i'm not an installer but I think it now goes:
G99 FastTrack - Allows an inverter of >3.68kW to be installed so long as it has export limitation (G100) of =<3.68kW. Essentially you get 5kW AC into your house when needed but can only pump the same as a G98 inverter back to the grid when exporting.
Full G99 is if you want >3.68kW Export- Needs approval BEFORE install (lest you get rejected this makes things difficult if you've already bought it) usually incurs a fee (think mine was £250) as someone has to check your street cabling on a database and come up with a maximum allowable export figure. You may simply get knocked down to 3.68kW export anyway (which seems to be quite common now just to get the sea of applications off that depts desk)

I think the maximum installed export capacity for domestic all told is around 17kW but i doubt anyone would get anywhere near that approved.

Note 1: GE Inverters have a lot of headroom on the Hybrids on the DC side so you can (should your array be big enough) max out the inverters AC capacity while also filling the batteries at full rate. i.e my Hybrid 5kw Gen 1 can actually top out at 7.6kW (5kW to AC & 2.6kW to the battery) at the same time. This doesn't work in reverse though so DC to AC is 5kW no matter what.
Note 2: If you don't plan to export much (i.e have a hot water diverter & an EV to dump excess into) then it basically comes down to whether you will regularly need to use more than 3.68kW of AC or not. But i'd personally want the bigger inverter for future proofing.
Note 3: I've just realised who I'm replying to and think you've a whole thread on this planned install already so you probably already know all this :-)

Thanks all for the replies.
What is still not clear to me is the visibility of power and energy values provided on the cloud portal, say with 1 x AC3 inverter with it's own EM115 grid and a/c output meters, plus 2 x EM115 to monitor the a/c output of 2 x solar PV systems.
Do you get live and historical data on all of these meters, individually or summated, or just live data with no historical on some for example?
1/ Grid - Live + Historical - Yes - Seen on demo portal.
2/ AC3 - AC input/output - Live + Historical - Yes - Seen on demo portal.
3/ Solar PV 1 - Unknown.
4 Solar PV 2 - Unknown.

My experience with a MyEnergi Zappi, is that you can add a wired CT to monitor the a/c output of a GivEnergy hybrid inverter (configured as Gen & Battery), and you can see the live power value, but there is no data logging provided as it is deemed not to be a MyEnergi device and it would add to their data-centre bandwidth and storage overhead.

I just use the AC3 for all of my data. I do not collect data from my other 2 inverters. It is not 100% accurate but its close enough.

For a zappi you will need 2 harvi's as well and 4 ct clamps. 1 for mains, 1 for each PV and 1 for the battery if hanging off the AC3. Then yes you can set one clamp as gen to avoid draining the battery. I have this very setup.

THALL @Simon_C if you haven’t started your installation yet, you could consider connecting all your inverters to one new “solar”consumer unit and then connect the isolator on that to a large enough MCB (45/63A) with a suitably sized cable on your existing consumer unit. That way you could reduce the number of CTs you need and simplify the logic about where the generation is coming from.

@Tim . As a minimum I would want to know the total solar output, which presumably would need 1 x EM115 and 1 x CT with the 2 live cables from the solar inverters passing through it.
Then 1 more EM115 would be needed to monitor the grid import/export at the main consumer unit in order to correctly control the AC3.

I guess what I am trying to understand, is what live values and what historical power and energy values will be visible via the cloud portal when 3 x EM115 are used with ID1=Grid, ID2=PV1 and ID3=PV2 as per the AC coupled plant diagram published by GivEnergy (but with only 1x AC3 inverter).

https://kb.givenergy.cloud/article.php?id=59

I would hope for the following for the historical power:-
1-Grid import/export.
2-PV1 generation - actual bell shaped curve for each day, and ideally a comparison with the forecast from SolCast.
3-PV2 generation - actual bell shaped curve for each day, and ideally a comparison with the forecast from SolCast.
4-AC3 charge/discharge
5-House consumption - Calculated as a result from all the measured values.

Also hoped for but not expected:-
6-Total PV generation - actual bell shaped curve for each day.

Can anyone indicate which of these they get, and what physical meters they have to achieve it?

Simon_C

I have 3 solar inverters.
All 3 are wired back to a single RCBO in the consumer unit.
So 1 CT on this feed shows total PV across all 3 arrays.
Each array is measured from it's own Solax App should I need individual panel string performance.

Then 1 ID1 eM115 on Import meter tail. Well actually also in the consumer unit live input.