question

Edgar Graadt van Roggen avatar image

Prioritize battery vs. grid use during certain hours of the day

My customer wants to have a grid-tie solar system which functions primarily as an off-grid system and only accesses the grid if there is not enough solar or battery capacity. He has chosen an electricity tarif scheme in which the electricity price is high during peak hours (18:00 - 23:00) and low in the other off-peak hours. He wants his system to function off-grid during. the peak hours and avoid and electricity purchases during those hours. Outside of the peak-hours, he wants the system to revert to grid-tie and be able to use the grid to recharge the batteries (in case solar is not enough). Is it possible to program the Multiplus to be grid-tied during certain hours of the day and be off-grid (functioning as a UPS) during other hours of the day?

offgrid
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2 Answers
Edgar Graadt van Roggen avatar image
Edgar Graadt van Roggen answered ·

Thank you Justin! Very helpful. I will look at the instruction set. Thank you!

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Justin Cook - Bay Marine Supply USA avatar image
Justin Cook - Bay Marine Supply USA answered ·

@evanroggen, something very similar is possible, if you're willing to allow grid-tie to be determined by SOC rather than specific time; I don't know that any Victron products have reliable clocks in them, so using a time determination might be tricky. But for SOC determination, you just wire the relay-out on the back of a BMV to the AUX input of your Multi and then use a total of 3 Assistants in the Multi; in short terms, you tell the Multi to ignore AC input unless the battery bank falls below a set SOC.

See complete instructions here: https://www.victronenergy.com/live/dc_coupling:using_bmv_soc_in_a_vebus_assistant_setup


Alternatively, I suppose you could always just wire a clock to an AC relay that connects/disconnects the AC In on your Multi...

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