question

PeterM avatar image
PeterM asked

Multipus AC output feeding another Multiplus AC input

I would like to add another large battery capacity ( perhaps Lithium or Lead Carbon ) to an existing Home UPS ( Multiplus 5 kVA 340 AH ) setup. I was considering getting another Multiplus which would manage the new battery and Solar PV inverter and its output would then be AC feed IN to my existing Multiplus effectively replacing the previous Utility grid . Would this work ? Would the downstream ( old ) Multiplus not complain about source impedance perhaps ? What is the maximum source impedance that it will tolerate?

MultiPlus Quattro Inverter Charger
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3 Answers
Guy Stewart (Victron Community Manager) avatar image
Guy Stewart (Victron Community Manager) answered ·

This is not Victron advice, but my own experience.

I have done this and it worked very well.

I actually made a schematic.

1:1 rule applies too.

Again, This is not a Victron approved diagram, just a system design that I have used that worked. It was a lithium battery and solar upgrade to power Air Conditioners to an old, but not yet failed lead acid battery.


screen-shot-2019-03-31-at-80712-pm.jpg (254.6 KiB)
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PeterM avatar image PeterM commented ·

Very much similar idea I had , just will have AC Solar inverter on the one and perhaps DC MPPT on the other

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Anders avatar image Anders commented ·

Very nice Guy - thank you !
I want to do something similar, but the energy supplying part is a Electric Vehicle, and the inverter can not be as large as the main inverter (5000W).

The car can deliver 3000W 12V, I consider stay below 2000W. Would any of the smaller Victron inverters be able to do this?
vehicle-to-battery-long-distance-1.jpg

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vehicle-to-battery-long-distance-1.jpg (18.5 KiB)
Anders avatar image Anders Anders commented ·
Just an update - I am running this setup now - works fine
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tedownes avatar image tedownes commented ·
Is there any issue with running this system setup with no grid attached to the first multi so it is in inverter mode always. I'm wondering what happens if the second multi is assisting the first multi due to large load and then the load is switched off. The two units are both pushing out power and neither are expecting to need to absorb any excess when the load turns off, could one multi break the other? Is an assistant needed somewhere to help with this?
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amacris avatar image amacris commented ·
I am thinking about doing exactly this. My only concern is that I might exhaust the new 48 Volt lithium batteries in order to charge the old lead acid ones since multiplus is an inverter/charger
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amacris avatar image amacris commented ·
I am thinking about doing exactly this. My concern is that I might exhaust the new 48 Volt lithium batteries in order to charge the old lead acid ones since multiplus is an inverter/charger
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amacris avatar image amacris commented ·

I am thinking about doing exactly this. My concern is that I might exhaust the new 48 Volt lithium batteries in order to charge the old lead acid ones since multiplus is an inverter/charger

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Craig Myatt avatar image
Craig Myatt answered ·

Some of the issues is that question have been addressed here: https://community.victronenergy.com/questions/10571/combining-a-non-victron-inverter-with-a-victron-mu.html. As to impedance...not sure.

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amacris avatar image
amacris answered ·

I am thinking about doing exactly this. My concern is that I might exhaust the new 48 Volt lithium batteries in order to charge the old lead acid ones since multiplus is an inverter/charger

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