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peternielsen avatar image
peternielsen asked

Disable inverter in a ESS system

Hi,

I have a Multiplus II, Cerbo GX, Victron MPPT and a Fronius inverter. The fronius is on AC IN. The system works fine. When there is sun MPPT charges the battery together with the Multiplus II from the energy produced by Fornius as long as the house load is covered first.

My electricity price is variable and changes every hour, i have made some automation in Nodered to start charging EV when the electricity is at it's lowest BUT i don't want to use the battery for charging the EV since i want to buy from the grid. I want to keep the battery when the energy is expensive.

I have access to Modbus and MQTT so i am looking for suggestion what i should do in case i don't want to discharge from battery. I tried the Switch mode from Modbus 33 to set to Charger only and that works since the MPPT can continue to charge battery while i buy from grid but the question is, is that the correct way to do it ? There are also Hub4/DisableFeedIn but the name doesn't sound correct because i want DisableDischarge. Maybe setting the gridpoint could do this ?

/peter

Modbus TCPMQTT
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3 Answers
baxter avatar image
baxter answered ·

Maybe by setting the discharge current limit DVCC: DCL = 0

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peternielsen avatar image peternielsen commented ·

Yes that might be one option if i was using DVCC but i don't, nevertheless i think there are different options doing the same but i think some are more right than others. @mvader (Victron Energy) or @Daniël Boekel (Victron Energy Staff) you probably have a good idea ?

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Daniël Boekel (Victron Energy Staff) avatar image Daniël Boekel (Victron Energy Staff) ♦♦ peternielsen commented ·

did you try 'disable feedin'? I think that would work..

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peternielsen avatar image peternielsen Daniël Boekel (Victron Energy Staff) ♦♦ commented ·

@Daniël Boekel (Victron Energy Staff) es and i can see very short time the inverter goes into Charger mode but then goes back to Discharge mode. I don't know why. Nobody is controlling it. Maybe ESS does this ?

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Matthias Lange - DE avatar image
Matthias Lange - DE answered ·

Connect the EV charger before the ET340/EM24 (or what ever you have installed as grid meter).
This way the load of the EV charger is not seen by the Cerbo GX.

Why you don't use DVCC? This would be an easy way.

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peternielsen avatar image peternielsen commented ·
Ohh i can't change the installation now, well to be honest i don't know what benefits i get by using it ? What am i missing, i only have the Multiplus II and one Victron MPPT
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peternielsen avatar image peternielsen commented ·
Ok so i enabled DVCC but i can't find what the setting for DVCC DCL is called either in Modbus or MQTT, any ideas ?
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baxter avatar image baxter peternielsen commented ·
Look into the modbus register list.
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shaneyake avatar image
shaneyake answered ·

The easiest way I see to do it is to limit inverter power. It is in the ESS menu. I think the register is 2704 ESS max discharge current. You can just set that to like 10W while you are charging.

Disable feed-in won't work unless you are running in ESS mode 3, as in Mode 1 or 2 the ESS control loop on the gx will overwrite it.

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peternielsen avatar image peternielsen commented ·
The loop you are mentioning is what i was experiencing, it was getting overruled. I will check the max discharge current, that sounds promising.
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