sieade245 avatar image
sieade245 asked

Clarification of Fronius IG plus power limiting/ zero feed in needed

Hello. I'm thinking of moving my Fronius IG plus PV inverter from AC Input coupled to AC output coupled so it will still work and power my house in a power cut. I'm not 100% sure on if this is possible though as although the IG plus is in the supported inverter list on the Victron Fronius PV inverter guide, it also says that zero feed in is not supported with the IG plus. Does this also mean that power limiting is also not supported on the IG plus as well or just zero feed in...or are they both the same thing? (I don't need zero feed in)

MultiPlus Quattro Inverter ChargerESSFronius
2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

3 Answers
Guy Stewart (Victron Community Manager) avatar image
Guy Stewart (Victron Community Manager) answered ·

Hi Sieade,

There are several levels of 'support' for AC solar inverters on the AC output.

Doesn't Work (rare)


Works with generation data

Works with data and advanced controls like Zero feed in.

Anytime you would be connecting an untested AC inverter on the AC Output I would watch the behaviour EXTREMELY closely to make sure the settings behave as you would expect. That involves full charges, and close observation ready to disconnect manually and reconfigure.

And of course read all the available manuals such as this:

2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

sieade245 avatar image sieade245 commented ·

Hi Guy thanks for the quick response. Here are some snippets from your link which I'm still unsure of:

So my inverter is the bottom one on the list there, it says compatible...does this mean it is compatible with the frequency shifting as further down it says

But I have the IG plus so so far so good...but then on the ESS manual page it says:

and then in 4.3.11 it says

So I'm still a little unsure. I need to buy the datamanager first in order to test it would work as mine doesn't have one fitted but this is quite an expensive gamble if it won't!

Is it possible that one of the victron manual pages was written earlier than the other one and things have changed? The IG plus firmware 5.0.66 is a fairly recent one. Looking at the Fronius changelog, this is the firmware where they seem to have added power reduction

0 Likes 0 ·
1554030348892.png (122.8 KiB)
1554030470380.png (23.4 KiB)
1554030554367.png (23.8 KiB)
1554030647115.png (57.0 KiB)
1554031486424.png (168.3 KiB)
Guy Stewart (Victron Community Manager) avatar image Guy Stewart (Victron Community Manager) ♦♦ sieade245 commented ·

As long as you don't require the Zero-Export feature, as in you are ok for your solar inverter to export to the grid, then you should be fine.

Zero-Feed in is different to power limiting.

When the grid is connected the Multi cannot shift the frequency, so the the inverter can't get the 'normal' signal that it needs to power down when the batteries are full. So the surplus needs to flow out to the grid.

With some Fronius inverters, a data signal can be sent back to the inverter and used to adjust it's power output WITHOUT needing to adjust the frequency. This allows for a grid connected, zero-feed in situation.

Your inverter cannot be controlled via the data signal, it will require the frequency to be adjusted for it to reduce its power output.

You should get production data from the system though with the Fronius data manager card. You could also use one of the other energy meter options as well.

0 Likes 0 ·
sieade245 avatar image sieade245 Guy Stewart (Victron Community Manager) ♦♦ commented ·

Beauty! Thanks Guy just what I needed. Now I just need to find one of the data manager 2.0 card for the IG plus 4,240,034. They're like Unicorns. It definitely won't work with the data manager 1 (not the cheaper com card/ data logger)? As I can find these but no 2.0s

0 Likes 0 ·
sieade245 avatar image sieade245 sieade245 commented ·

I've done a bit more digging. As far as I can tell there are subtle differences between the datamanager 1 and 2:

2 has modbus

2 has wifi

2 has slightly different port configuration

They both seem to use the same firmware/software though.

I've read through the guides and the connection between Victron and Fronius appears to be on the local lan so I'm assuming this is the only port needed which both have and because the software is the same, data reporting on the LAN would be the same. As long as MODbus is not required from the Fronius I think the datamanager 1 would work. Is anybody else using datamanager 1 with any Fronius inverter?

0 Likes 0 ·
Paul B avatar image
Paul B answered ·

another way to do it is to use assistants to disconect ac1 in when the battery gets to say 98% and then reconnect when it drops to 95% SOC or volts can be used and gen autostart and stop etc

Beokel has shown examples of how to do this in a few of his posts.

I use another brand of Grid Tie inverter that shuts down using Frequency shift but to do it mains has to be disconnected

one example which is different from what you need but it gives the idea is

2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

sieade245 avatar image sieade245 commented ·

Paul I think I follow you. Do you mean have the inverter on AC Out 1 and all loads on AC Out 2? So when AC Out 1 is disconnected, the inverter shuts down but all loads are still powered from the batteries via critical load/ AC Out 2? And then when battery depletes, the inverter is switched back in via reconnecting AC Out 1?

0 Likes 0 ·
Paul B avatar image Paul B sieade245 commented ·

No all the loads stay on AC out 1

if you turn ignore ac1 in on then you loose power on ac2 out but ac 1 out still has inverter power.

the assistants are used so that the unit is disconnected from mains so that freq shift can be used if you don't want to export power you would use different selections in the Autostart area maybe SOC but what ever achieves the objective

0 Likes 0 ·
1554068003449.png (19.3 KiB)
boekel avatar image boekel ♦ commented ·

Why would he want to disconnect it? he now has it connected to the grid, so feedback is no issue.

0 Likes 0 ·
sieade245 avatar image sieade245 boekel ♦ commented ·

I would need to disconnect it if I couldn't use power limiting on the Fronius. If there is no load and the batteries are already charged, the solar power would have nowhere to go and something would blow up. By turning off the AC Out, this instantly switches off the PV inverter due to LOM safety detection. This would only happen in a power cut, normally the excess solar PV is fed back

0 Likes 0 ·
boekel avatar image boekel ♦ sieade245 commented ·

When during a power cut the batteries are fully charged, the Victron inverter will use frequency shift to switch off the PV inverter. these are standard settings if you configure the ESS assistant.

0 Likes 0 ·
sieade245 avatar image sieade245 boekel ♦ commented ·

Hi Boekel. That's an important piece of info there. All of the victron documentation I've read suggests that extra equipment is needed in the form of the Fronius datamanager for them to work together which I don't have. Are you saying that I don't need it? Is it only for solar power monitoring? Because they are rare and expensive and I could use a simple AC current clamp to measure solar yield. I thought I would need to purchase the datamanager because there is no inbuilt firmware upgrade port (USB/ SERIAL etc) on the Fronius IG Plus and I have an old firmware not up to 5.0.66 revision. Do you think the Fronius would still cut the power off with frequency shift?

0 Likes 0 ·
boekel avatar image boekel ♦ sieade245 commented ·

If you're not sure than check with your Fronius supplier, I'd be surprised if it doesn't support frequency shift.

The 'zero feed in' function is to regulate the PV inverter while connected to the grid, so no frequency shift is possible then.

You can easily try the function by connecting the inverter to AC-out and and charging to 100% soc without grid connected. it should start frequency shifting as soon as the charger cannot supply all the PV power into the batteries anymore.

Points to make sure:

-respect the 1:1 rule, PV power should be the same or less than Victron inverter

-your batteries have to be able to handle the full charging current also.

If any of the above is not ok, the AC and/or DC voltage will shoot to high and the Victron will shut down.

0 Likes 0 ·
sieade245 avatar image sieade245 boekel ♦ commented ·

That's very helpful thank you for the info. I will give it a try.

I've just found the latest manual for my IG PLUS and it does appear to support GFPR. I can't check right now because the inverter won't work with no solar power but I'll take a look tomorrow in the settings menu. If it does, I think all I need to do is maybe review/ change the frequency settings for reduction/ disconnect to match the Victron settings for ESS assistant. I think maybe the 5.0.66 firmware already has these figures but maybe mine doesn't. It's all a bit guesswork right now I'll take a proper look tomorrow. If it can work without a firmware update, theres no need for me to buy the datamanager, you might have just saved me at least £100!!

0 Likes 0 ·
masi avatar image
masi answered ·

Hi, my Fronius IG-Plus 3.0 is working well in ESS AC coupled system(Fronius on AC Out of Victron). Only the issue is that in case of a big surplus(not sure the %) the Fronius can not reduce the power but it is going standby

2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.