Dual Inverters

[reef]

I'm currently running a 4.8kW SE facing array on a H1 5.0-E and am getting a second 4.6kW array installed on the opposite NW roof. The installer has recommended an F3600 inverter for the second array but I'm unsure how this works and have a few questions?

Will the new F3600 inverter be able to charge the 5x HV25 batteries that reside on the H1 5.0-E? Also when it comes to the solar, assuming both arrays hit 3kWh for example mid-afternoon in the summer, can the house essentially use 8kW i.e 3kW + 2kW from battery (5kW) on the H1 plus the 3kW from the F3600 at the same time?

Is it usual to run this way instead of just one larger inverter such as a KH 9.0? I understand we'll probably never top 6kW of PV with the opposing roofs and think the NW array will rarely trouble the 3.68kW limit on the F3600, but will it all play nicely?

Thanks in advance.

[Dave Foster]

You may be stopped by your DNO on the larger inverter, so really a quick call to them to find out if they would grant approval for an inverter of that size being connected to the grid.

The F3600 is as you know a solar only inverter and works well with the Hybrid, you would attach a second CT clamp off the Hybrid to the output of the F3600 so that it knows about the extra generation in the home, and spare it will use to charge the batteries. On your can the house use question, in short yes the house use will be equal to the maximum of both devices (assuming solar and battery allow), but your export may be limited by your DNO.

If you have a G99 for a 5kw inverter and have only been granted 5kw maximum output then you would either have to limit the maximum export on the Hybrid inverter (you can still use it in the house, charging your batteries), or you would need to re-submit for a larger G99 export limit.

[reef]

Thanks that's really helpful.

We are indeed resubmitting the G99 as we'll need more than the current 5kW export regardless.

At present we can discharge from the batteries at up to 5kW with the H1-5.0-E. I was originally drawn to a larger inverter in the first place as we have an 8kW electric shower and often use many things at once (we have air con, two ovens etc). I'm guessing that's the major limitation of one large vs two smaller inverters - we can hit >5kW, but only with solar on the F3600 to make it up as it cant use the battery itself being non-hybrid?

[reef]

Just bumping this as I have had the F3600 installed alongside my H1-5.0-E and I have a question.

I notice on the F3600 there is no wifi dongle. Is this not required when two inverters are used? I was under the impression both would have one and that way I could see both in the cloud. They are connected via a CT clamp so the H1 will be able to see the F3600 but I take it I wont be able to if there's no dongle?

I was under the impression all Fox inverters come with one?

[Dave Foster]

The dongle on the F-series is optional as they are often used in the configuration you have with an H series monitoring it’s total solar generation via CT2.

If you don’t have one you can easily add a wifi dongle (datalogger) to it and add that datalogger to your account and you will then have access to it’s individual plant statistics for each of the pv strings, voltages etc..

[reef]

Thanks for the reply.

How will it work as it stands? Will I see anything on my H1-5.0 on the cloud that will indicate its all working as it should?

It looks like I'll have to get the dongle as I like to see what's going on. I'm a bit annoyed my installer didn't do this as I was under the impression I would have full monitoring.

[Dave Foster]

How will it work as it stands? Will I see anything on my H1-5.0 on the cloud that will indicate its all working as it should?

It looks like I'll have to get the dongle as I like to see what's going on. I'm a bit annoyed my installer didn't do this as I was under the impression I would have full monitoring.

Assuming the F series has been connected to your H1 using the H1's second CT clamp, the Hybrid will be fully aware of any charge coming from this inverter, it will use that generation to charge the batteries and to balance any export.
The cloud app (and also Energy Stats) would show an additional source of generation coming from the second CT clamp and you will be able to look at the generation history.

Having the extra dongle on the F-series would give you access to drill down into more detail on individual solar strings, to look at the voltages, power etc.. and to remotely update firmware should new releases come out - the majority of that information can be seen in real time on the inverter itself, but the dongle would give you the ability to view statistical history.

[reef]

Yes, there's a CT clamp from the F3600 to the H1-5.0-E so I can see the power it is sending over but that's all. Energy Stats and the Fox app show this also, but report it as a third-party inverter due to the lack of Wifi on the F series. Also worth noting the new 'PV yield' on energy stats does not count CT flow as PV yield, even if you select for it to be inverted and merged with the primary inverter PV flow in the options so I might fire the developer off an email and see if this is possible in a future update.

Anyway I've spoken to my installer and they are sending a dongle so hopefully Ill be able to see everything soon. The H1 and F series are working very well together so that's a plus.

[AlanHarwood]

I have a rather similar setup, but with two H1-5.0-Es.
Both have dongles.
The App still shows the output from the second inverter as if it is an unidentified source which cannot show any details, and when it is receiving nothing from is PVs, it disappears from the picture. The other strange thing is that although the net output from the second inverter is clearly show, it doesn't add it into the "Power Now".
The second dongle appears to be working perfectly (I can "ping" it), but I don't know how to get any information from it.
Have you installed your second dongle? If so, do you have the same problem?

[reef]

Yes, mine shows the same. The second inverter vanishes from the screen of the first when there is no PV. In the app it shows it as a 3rd party inverter (or "gen" in v2.0 app). The Fox app/cloud treats each inverter as different entities for me so generation on inverter 2 doesnt show in the totals of inverter 1 (among other issues, see my thread on "Load Power).

When you go onto the main page of the app, does your "site" name have a small down arrow next to it? It could be that like mine, it has been added as a second identically named site. If so, you should have two options here with the same name and each will be one of your inverters. You'll then find the information from inverter 2 in there.

[AlanHarwood]

Yes, the site name does have the little down arrow, but that shows that there is only one site for me, so I can't see the inverter2 information.

[AlanHarwood]

I've just found that if I try to add the serial number of my second dongle, it says that it is not bound to any site, and gives me the option of creating a new site: it does not give me the option to add it to my current site. Presumably if I had said "Yes" to the new site option, I would have been in the same position you're in.

[reef]

Yes, you can add it, but unless it's the same installer account at the same time, it seems it just adds it but as a second identically named site. I tried everything and couldn't get it on the one site, nor could my installer. I guess its just an annoying limitation of the system.

[AlanHarwood]

Can your second site see the first site, and does it appear as just a single item?

[reef]

Can your second site see the first site, and does it appear as just a single item?

No unfortunately not. They act as identically named independent sites.

[AlanHarwood]

I created a second site using the serial number of the second dongle, and as expected all it could see was its PV and Inverter.
I then deleted this new site.
I then found that the original site now had a choice of either inverter, but not both at the same time.
I'm not sure if that counts as progress!

[AlanHarwood]

I should have added that what I did had no effect on either version of the Android app, only the PC program was affected.

[AlanHarwood]

It occurs to me that the reason the second inverter cannot see the rest of the installation is that it has no CTs. Do I need to add 2 CTs, one on the main live and the other on the output of the first inverter, or will that completely confuse things?

[Dave Foster]

It occurs to me that the reason the second inverter cannot see the rest of the installation is that it has no CTs. Do I need to add 2 CTs, one on the main live and the other on the output of the first inverter, or will that completely confuse things?

I'm assuming you have a hybrid and a solar only inverter ? - if that's right you should have 2 CT's on the hybrid and no CT's on the solar only inverter.

The hybrid should have one CT on the main feed from the smart meter and the other on the live feed of your solar inverter.

EDIT: sorry just read your earlier post, you have 2 hybrids in series so it would be more like this.

Having them in series is the only way they will operate without competing, the main inverter would have 2 CT clamps fitted to monitor the smart meter feed and the other hybrid output, the second hybrid would have one CT clamp fitted that only sees its output.

This is an older install but shows the method behind the install, the red wire is CT2

[reef]

I created a second site using the serial number of the second dongle, and as expected all it could see was its PV and Inverter.
I then deleted this new site.
I then found that the original site now had a choice of either inverter, but not both at the same time.
I'm not sure if that counts as progress!

That's pretty much all you can do unfortunately. I have not found a way to get both showing on the same site together, even with a CT clamp between them.

With CT clamps, as Dave mentions above you want the primary inverter to have a CT on the mains and a second CT clamp to the second inverter. This then allows the primary inverter to see what the second is generating and balance loads / charge the batteries etc. In my setup I have a hybrid H1-5.0-E with batteries attached and secondary F3600 solar-only inverter. The H1 has a CT on the mains and then a second connects the F3600 and the H1.

I'm not sure how this would work with your two hybrid inverters and if they would play nice together. I suppose in theory you could have batteries and a CT clamp to the mains on both. I've no idea if it would work correctly though!

[AlanHarwood]

It occurs to me that the reason the second inverter cannot see the rest of the installation is that it has no CTs. Do I need to add 2 CTs, one on the main live and the other on the output of the first inverter, or will that completely confuse things?

I'm assuming you have a hybrid and a solar only inverter ? - if that's right you should have 2 CT's on the hybrid and no CT's on the solar only inverter.

The hybrid should have one CT on the main feed from the smart meter and the other on the live feed of your solar inverter.

EDIT: sorry just read your earlier post, you have 2 hybrids in series so it would be more like this.

Having them in series is the only way they will operate without competing, the main inverter would have 2 CT clamps fitted to monitor the smart meter feed and the other hybrid output, the second hybrid would have one CT clamp fitted that only sees its output.

This is an older install but shows the method behind the install, the red wire is CT2

IMG_1554.jpeg

My setup has the two inverters in parallel. I had assumed that it was set up that way because of the limit of 5KW AC through the inverters, but on looking through the manual I see that it says 5KW or 5kW+5KW (bypass). Would wiring them in series mean that the output of the first one would be "bypassed" through the second, thus avoiding the 5KW limit?
I'm not sure how your third CT works: is the CT clamp on the second inverter connecting to the output of the first inverter, i.e. both inverters are connected to eachothers output?
If I leave my inverters in parallel, but fit the extra CT clamp, then would the problem of competition/confusion only occur once I add a second set of batteries?
As you've probably gathered, I'm new to all this!

[Dave Foster]

My setup has the two inverters in parallel. I had assumed that it was set up that way because of the limit of 5KW AC through the inverters, but on looking through the manual I see that it says 5KW or 5kW+5KW (bypass). Would wiring them in series mean that the output of the first one would be "bypassed" through the second, thus avoiding the 5KW limit?
I'm not sure how your third CT works: is the CT clamp on the second inverter connecting to the output of the first inverter, i.e. both inverters are connected to eachothers output?
If I leave my inverters in parallel, but fit the extra CT clamp, then would the problem of competition/confusion only occur once I add a second set of batteries?
As you've probably gathered, I'm new to all this!

Is there any chance you could post a schematic of how your system is installed - the installer should have left you a basic sketch as part of the G9x process.

[AlanHarwood]

The installers sent me an email enclosing the schematic yesterday. Unfortunately it only showed one of the inverters, and was missing some other parts too. I have asked for a corrected one.

[AlanHarwood]

After sending me three versions of the schematic, none of which actually matched what they had installed, they finally admitted that the two H1-5 hybrid inverters could not work in parallel, and they are swapping them out for an KH10.
This reduces the maximum number of batteries I can attach, but it's probably enough, and if it isn't, KH10s are designed to work in paralllel, so I'll still have a way to expand if necessary.

[Dave Foster]

After sending me three versions of the schematic, none of which actually matched what they had installed, they finally admitted that the two H1-5 hybrid inverters could not work in parallel, and they are swapping them out for an KH10.

Great, I didn't want to comment until I saw your schematic but that was what I suspected, having the new KH10 makes much more sense, smaller, more efficient and very capable