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natteverf avatar image
natteverf asked

Assistant assistance

Hi
I have a Quattro, two mppts, smart shunt and Venus OS Large all set up on a boat which has shore power most of the time, batteries are Super AGMs. My objective: fully charge the batteries using solar only and when they are full, or rather when the mppts are both on float, then start using the inverter until the battery soc gets to 56%, then switch to shorepower again until the batteries have been recharged using solar again. I have tried to achieve this using generator start stop assistant and general flag user assistant to "Use general flag to ignore AC input 2". DVCC is on. I cannot quite achieve this with these assistants, I was thinking that there should be a way using Node Red but the VE bus system control settings are very limited. I am open to suggestions, any help would be appreciated.

MultiPlus Quattro Inverter ChargerMPPT SmartSolarNode-REDAssistants
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2 Answers
matt1309 avatar image
matt1309 answered ·

Hi @NatteVerf

You could look into virtual switch/AC ignore assistant however I think the criteria for activation might be quite limiting for your setup.

The other option i can think of is maybe using Node red to change the multiplus switch position to inverter only? I think this is probably better as you'll have way more flexibility with the on/off criteria in node red ie could eve add disabling the behaviour during certain periods of the year etc.

This thread seems to ask for something similar:

NodeRed - Ignore AC Input 1 - Multiplus II - Victron Community (victronenergy.com)

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JohnC avatar image
JohnC answered ·

Hi @NatteVerf

You don't say what your specific problem actually is, so it's hard to help.

What stands out though is the wide range of battery SOC you're attempting to cover. Like at mppt Float you may be 99% SOC, and have already lost a lot of potential solar charge during Absorb. Why not use the SOC when entering Absorb, maybe 95%?

At the lower end, 56% puts Pb batts into serious V sag territory if they were to be loaded a little. Your choice, but 75% would be the lowest I'd go.

Whether you actually charge when you bring on Shore is another consideration. You might limit that, or set a flat Float V in the Quattro. Or even use the Charge Current Control Assistant, but a little trickier to set up.

Just using SOC should work fine with Assistants. Don't overthink it with theory, which mightn't do what you want anyway. Start with the easy stuff and refine it as you learn what you really need.

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