question

matthiasu avatar image
matthiasu asked

Battery full, Multi+ESS feed to grid higher than AcPowerSetpoint

Setup: my battery is full, DC voltage is equal to what the BMS says is the maximum. I'm telling my set of MultiPlus 3000 (3-phase setup, controlling phases separately) to send a total of 700W to the grid (external control, writing to /Hub4/L[123]/AcPowerSetpoint. However, the Multis don't listen and output 1300W. Apparently because that's (part of(?)) what the solar array wants to deliver right now.

I don't like that. If and when my energy provider tells me that there's enough energy out there and to Not Feed The Grid, my system *must* listen, otherwise I won't get any money for the energy I do feed to the grid.

Any idea why that happens and how to fix it? (Yes, I'm writing these AcPowerSetpoint values every couple of seconds. This setup works perfectly if the battery happens to not be full.)

Edited to add: solar power is from a couple of Victron DC chargers which are perfectly capable of shutting down when the voltage reaches the maximum set by the BMS.

Multiplus-IIESS
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2 Answers
wkirby avatar image
wkirby answered ·

For AC coupled PV Inverter, you need to instruct the PV Inverter to limit its power output. When the MultiPlus is connected to the grid it cannot frequency shift to limit AC PV Inverter output, it can only do this when AC Input is disconnected.

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matthiasu avatar image matthiasu commented ·
I don't have an AC coupled PV inverter. The solar chargers are a couple of Victron BlueSolar and SmartSolar devices which are perfectly capable of shutting down when the battery is full.
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nickdb avatar image
nickdb answered ·

Moved to modifications.

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