Can I chain Multiplus and use Power Assist to have more power ?

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mildred asked Dec 27, '21

Can I chain Multiplus and use Power Assist to have more power ?

I find it hard to get information on how the Multiplus works. I own a Multiplus 48V 5000VA 70A and for a long time I thought that the maximum current draw from the battery was 70A while it seems it's in fact close to 105A (5000/48). I also thought that the maximum output power was 4000W(5000VA) but on the enclosure it's written "AC transfer capacity 100A". Can the Multiplus deliver more than 4000W if it has its AC input providing the needed power to compensate?

My goal is to extend the system because I am frequently overloading it but I cannot extend the battery pack because I don't want to mix different batteries together. I'd prefer to create a second battery pack. Something like in the following schema :

The second multiplus having a n AC transfer capacity of 1000A, it is more than enough to transfer the 4000W from the first Multiplus and produce in addition to the second multiplus inverter a total of 8000W.

Will this work?

What can make the second multiplus overload?

cascading inverters

2021-12-27-schema-multiplus.jpeg (194.8 KiB)

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Modifications Space

Node Red Space

Answer 1 · 2021-12-27T19:22:41Z

Alexandra answered · Dec 27, 2021 at 07:22 PM

@mildred

The question of a cascade setup has been asked quite a few times on the forum. It is not really an officially supported setup. There is even a tag for it, and it is discussed alot in threads without the tag.

To be honest I have found that it is easier and safer to split the DB board over the two inverters. The ideal way is a parallel system but with your two separate banks that is not really an option.

Transfer ability is referring to how much can pass through not how much it can produce. 4000W is what it can produce. And they can pass 100A through. But obviously it will overload if grid goes out.

With the current draw from the battery the amps go up as the voltage of the bank drops down so often you will draw more than expected unless the bank is massive. 5000va ÷ 48V is 104Amps so what you are seeing is what I would expect to see when the bank is carrying a full load. Or more if your voltage is sagging lower than that.

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kevgermany ♦♦ commented · Dec 28, 2021 at 05:09 AM

I think the AC in can be parallelled between the two as well. Not as shown in Mildred's diagram.

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