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fraserpyf asked

Multiplus with ESS exporting grid side AC PV whilst also discharging battery to load?

I have a brand new Multiplus 48/5000/70 set up in ESS mode.

All AC loads are connected on the AC1 output.

I have an existing 4kWp AC coupled solar array with an SMA inverter (SB3800 made in 2010) which is configured to connect on the grid side as it appears that it cannot be frequency shifted, to enable connection on the Multiplus AC out.

I am unable to connect the SMA directly to the CGX as it is too old. I appreciate that replacing the SMA with a new Fronius will probably sort this but I hope that there is a workaround that doesn't involve more expense

Therefore an et112 is used to read solar input which feeds into the CGX.

The CGX will often show the PV inverter generating power which appears to be being fed to the grid. This would be ok apart from the fact that any AC loads are being met by the battery!

I appear to be losing twice over ie discharging my battery AND exporting solar to grid!

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ESS
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Rob Duthie avatar image Rob Duthie commented ·
You can use a ET112 on the PV inverter output to measure the power flow correct?, have you also have a ET112 on mains input to the grid will be required so to read all the power flows correctly, This is what i have done with some systems to make it work correctly. And configure the ET112 as grid and PV meters.

Also the ESS setting for the battery is set to (MODE without battery life).?

Regards

Rob D

NZ


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Rod Krempaszky avatar image
Rod Krempaszky answered ·

Hi Frazer,

I agree with Rob D 100%. Many Victron systems with using any flavour GT inverter on grid side, the Victron uses this energy when grid available if programmed correctly. You have an SMA, that is compatible to place on grid or load side of Victron. You have on grid side. ET112 set to PV inverter for the SMA in this position, you do not need a Fronius. Working systems seen under ESS always gets the banana CT or mostly the ET112 for accuracy and set to grid meter. Your supplier (importer) of Victron should be supplying the support service you request with this set up and programming information.

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fraserpyf avatar image fraserpyf commented ·
Hi Rod,

Thanks for your input, I bought the new Multiplus as an upgrade to a 48/3000/35 that wasn't able to charge our 14.4kWh Pylontech battery in the 4 hour charging window available at cheap rate. I had installed and commissioned that one on my own and like to be able to do as much as I can whenever possible!

I also try to be as green as possible and so don't want to ditch a perfectly good inverter, if I can help it!

I will go for the second et112 and see if that sorts it.

As an aside, I have another 12 325W panels that I am going to install via Mppts to give a bit of solar input in case of a power cut...Im hoping that adding these don't cause any further issues...

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fraserpyf answered ·

Hi Rob, the simple answer is no!

I understood that if all loads were passing through the Multiplus, it isn’t necessary to install a second et112, as it will be able to measure any current flowing through it?

I am considering using the second outlet for essential loads in the future, but it is currently unused.

As you surmised, the existing meter is on the AC PV and appears to give reasonable readings compared to the ones showing on the SMA display.

The battery mode is “without battery life”.

Cheers

Fraser

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Rob Duthie avatar image Rob Duthie commented ·
What are the ESS settings? what are your assistants settings? and grid settings?
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fraserpyf avatar image fraserpyf Rob Duthie commented ·

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Here are a few screenshots. I’ll have to fire up the laptop and connect the mk3 to the MP to get some shots of the ESS settings.

There are no other assistants used.

cheers Fraser

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Rob Duthie avatar image Rob Duthie Rob Duthie commented ·
Hi

Need to set the battery moniter to Pylontech not the Multiplus as the charge controller.


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Rod Krempaszky avatar image
Rod Krempaszky answered ·

Hi Fraser,

As long as you get your work certified by an electrician who would inspect this with an inspection, you should avoid a fine and retain home insurance. High risk category installation.

The SMA being historic on the original installation will be fine, Use it until you loose it. Install the ET112 and set to PV inverter, also get the RS485 to USB cable ASS030571018 for communication to the ET112 from the GX device.

Agree with adding DC MPPT to the system. Once you get this up and running (high risk again, requires electrical worker for install of PV) You will see a much better picture of how the Victron breathes on AC coupled and DC MPPT PV. Blue Solar would do, slightly less cost as the BT function is not required with the Smart Solar version. Install with VE.Direct cable, then you can upgrade the MPPT firmware under VRM and then program the MPPT to Lithium parameters using Victron Connect from your lap top.



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fraserpyf avatar image fraserpyf commented ·
Thanks Rod,

Useful remarks. I have had all of my work signed off by a sparky. He’s happy to do this but isn’t interested in the complexities of getting it all running!

I’ve ordered the et112 and the rs485 to usb cable, so will get them put in asap.
I’ve already got the 3 100/20 mppt and the requisite VE direct cables (They are going to be In 2S2P for each mppt)

I will report back when the et112 is installed to let you all know how it works out.
Thanks again

Fraser

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fraserpyf avatar image fraserpyf fraserpyf commented ·

Hello all,

I have installed the second ET112 on the incoming grid.

I have updated the firmware in the Multiplus to 494.

The readings now being given for the Grid now appear to be accurate.

The readings for the Solar PV also appear to be accurate and the layout of the grid side of the CCGX and the VRM represent reality.

The system appears to be functioning as expected of an ESS system…


However the AC loads now also appear to be attached to the AC side of the inverter and is showing apparently random low figures for the loads being used.

If I connect a large load the battery icon shows the battery discharging at an appropriate rate (taking account of any solar input) BUT it does not show as a load.


Any ideas how I can resurrect the AC loads values AND get it represented as coming from the output side of the Multiplus?


Thanks for all your help so far.


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fraserpyf avatar image
fraserpyf answered ·

Hello all (again!)

Just spotted a new box to tick on the VRM to show AC loads!

Ticked the box and all is working perfectly!

Thanks again for all your help.

cheers

Fraser

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