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Paul avatar image
Paul asked

Feeding in surplus of MPPT250/100 without ESS assistant

Hi everyone


I have a system consisting of a MPII 5000/48, 8kWh of (batrium BMS controlled) LiFePO4 batteries, a Smartsolar 250/100 (12 panels in 3p4s config) , 14 panels on Enphase IQ7+ micro inverters, two Carlo Gavazzi's and a Cerbo running fine with ESS assistant active on the MPII 5000/48.

The batteries are quite old and I don't like to constantly charge/discharge them anymore.

I also want a more spread feed-in of 4,4 kW solarpower into the grid instead of a 4kW boost on just one phase.

So I installed a SMA STP5.0 3 phase inverter which will be the main producer of 4,4kWp power coming from the Smartsolar 250/100.

Now I want to disable ESS mode and connect the 5 extra panels to the Smartsolar 250/100 charging batteries directly. Specially during a longer outage.


When these are full, the Smartcharger normally stops and the access power from these panels is lost I presume.


Is there a way to feed in the surplus power into the net, WITHOUT an ESS assistant running?

It would be very nice to have a system in place that feeds in when the batteries are full, and charges the batteries during longer outages without having to switch the 12 panels on the SMA back to the smartcharger 250/100.


I am curious if somebody has already tried this setup.

Multiplus-II
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2 Answers
Paul B avatar image
Paul B answered ·

With out ESS the Grid code/mode is set to None and thus exporting is not allowed . even if you change the grid code to whats required for your country exporting still wont be allowed unless some assistant is installed

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mrhappy avatar image mrhappy commented ·

@Paul B

Is this really the case? I am searching the forum to find out how to feed in excess DC overvoltage from my system in certain circumstances. I do not want to use ESS assistants because I have my own fine-tuned system in node-red. I thought that I could set my grid code and enable address 65 (Feed DC overvoltage into grid) in my Multiplus-II via ModBus.

Can you link any documentation that confirm grid feed-in is impossible without ESS assistant?

Thanks,

MrHappy

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Paul avatar image
Paul answered ·

@Paul B Many thanks for your answer, I was doubting already.

I have already devided all my panels in 4 fields:

fied 1: 5 panels in series on the front of the house
field 2: 2 panels in series on the front of the house
field 3: 5 panels in series on the front of the house
field 4: 5 panels in series on the back of the house

These are conected to the SMA with 12 on MPPT-A and 5 on MPPT-B

I just keep using the Victron as a backup functionality until "shit hits the fan" and then just switch field 1, 3 and 4 in parallel on the input of the 250/100. then I can feed our backup batteries with 5,4kWp of solar power, enough to keep the lights running and use a small electric heater for some days.

It's a pity, Victron has no 3phase inverters.

Using 3 x MPII 3kW inverter/chargers makes things bulky and quite expensive too.

Although the toroïdal transformers are very compact and efficient, the noise they generate is something I didn't thought of too much, so I might end up buying an all-in-one solotion with HF technology and 3 phase.

Hope they will offer this kind of solution in near future.



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