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Multiplus AC Maxiumum output

I've read a lot on the documentation related the power assistant feature, but this is not clear: what is the limit of the ac/output?

Assuming that we want to use a Multiplus 3000, what happens if I want to connect on the input side an 8Kw generator and an AC load of 10Kw? What is the limit of the output?

MultiPlus Quattro Inverter Charger
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Paul B avatar image
Paul B answered ·

the units also have a limit of pass through amps being 16 amp or 50 for the multiplus 3000

so to pass 8Kw you would need the 50 amp pass through version,

then if the Generator was outputting 8Kw then the inverter would pass that through and then add up to another 3KVA to around a total output of 11kva could be achieved. or until the battery is exshausted that is.

you would need to set the power assist in the multi plus to say 45 amps or the max limit that the gen would do and the inverter can then supply the extra up to its own limits .

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Thanks a lot Paul.

raphael avatar image
raphael answered ·

One more question on this topic:
I want to use three MultiPlus II 48/3000/35-32 in a 3-Phase configuration with ESS for a house system with 10.4kWp Solar and 15kWh LiFePo4 battery.
The maximum AC transfer current (AC input current) is 32A for each phase.
When the grid is connected, is it possible to use power assist to get a output Current of 45A for each phase?

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In short: Yes.

Long: You will need to connect your entire house to the MultiPlus AC-out. PowerAssist doesn't work on AC-in (eg. it can't feed-in PowerAssist through it's AC-in)

Also, 3x3kW = 9 kW. At 48V that's almost 200 amps. You should check if your batteries can handle such a discharge rate.

Issue is.. What if you rely on PowerAssist, but your batteries are empty on a cloudy day? Then PowerAssist can't assist, and either your main breaker will blow or the inverter will shutdown/disconnect and you'll be in the dark. IMHO PowerAssist is a great feature for eg. a boat or a camper, but not so much for a regular home with permanent grid connection.

Last but not least.. I'm not sure where you are located, but fuse boxes in my country (Netherlands) are usually rated for a maximum of 40A. Both in terms of heat, but also, for example, GFCI's for household installations are limited to 40A. Connections in the fuse box are usually done with 6mm2 wires, which is also a bit small for 45A.

So if you want to do 45A you should check if your fusebox is up for the task. In my country the average fusebox wouldn't be rated for such high amps. But, a regular 3-phase grid connection here is 3x25A. So you having 3x32A is already a lot for us Dutchies, so maybe your fuse boxes are bigger too. I don't know.

Thanks for your Help!

Yes, the house will be connected to the AC out of the Multis. I'm located in Germany.

I got 300Ah LiFePo4 in a 16S configuration. So everything up to 300A should be fine.

Also, I don't need that much power on a regular basis...but in case we want to have a electric car charged in future, and cook at the same time, it should still work...I'm still waiting for the upcoming victron wallbox...maybe it'll be able to reduce the charge current of those phases, that are in a overload event.

I'd rather use 3kVA Multis instead of 5kVA, because of the price and the lower standby consumption...our average power consumption is only 11kWh/day.

We have a 63A Beaker at the input of the house...and we have three distribution panels, each with a 40A rated RCDs.

Right now, the 3kVA Multis would be enough...I'm just planing into the future...also we could increase our self consumption with the 5kVA Multis while cooking...our oven uses 3.5kW single phase case of a grid failure, we'd be in a overload situation already with the 3kVA Multis...But a higher standby consumption of 184kWh/a (7W*3*8760h) is quite something...especially in the winter months.

Yeah so those 40A RCDs should be replaced with 63A versions.

About the 3kVA vs. 5kVA.. I have a 5kVA, but it maxes out at about 3700 - 3800W on AC. My guess is that your 3 kVA will end somewhere in the ~2500W region.

I'm using a loadbalancing car charger. IMHO that is a better solution than charging car batteries from ESS batteries. If you'd use that you could maybe go with just 1 or 2 MPs instead of 3? And you wont have to connect your entire house to the MP's output, which makes the system more resilient. It would make the MP just an appliance, instead of a crucial device