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Richard Weir avatar image
Richard Weir asked

Multiplus 2 domestic battery system

I’ve installed a Multiplus 2 connected to 6 PylonTech batteries and Venus GX with the primary function of running my heat pump from off-peak electricity. I can’t get any advice on how to power the house system when the battery is fully charged. Do I have to have dedicated circuits in AC-OUT1 or 2?

MultiPlus Quattro Inverter Charger
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9 Answers
Jason - UK avatar image
Jason - UK answered ·

@Richard Weir You can have the house on AC in but you will need a CT sensor or a ET112 meter, and the power assist turned on in VE config, or you can have your house on AC out 1 limited to 50amps inc charging. In you use AC out1, the multiplus will use the CT sensor built in on the AC in. Dont connect the house to AC out 2 as in the event of a grid failure / power cut, AC out 2 automatically disconnects as its for non-critical loads.

Have a look at my photos on the below link, I have a schematic of my system. Note in the photos I hve a CT sensor on the incoming tails.

https://vrm.victronenergy.com/installation/171934/share/db6807bb

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Jason - UK avatar image Jason - UK commented ·

@Richard Weir I forgot to mention, I have a Mitsubishi Ecodan WM85 on the AC out1 of my Multiplus 5kva as well as all electric cooking (induction hob & electric oven). My ASHP don't pull more than 16 amps even when doing the last part of a hot water cycle. I charge on off-peak or solar and I have never gone over 50amps. I have a 32amp EV charger on the AC in side of the Multiplus because that would push the current over 50amps.

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johnone avatar image
johnone answered ·

This very much depends on the capacity of the system and your expected power need. For example, if you had a Multiplus II 48/5000 and you rarely consume more than 4kW at any one time, and never more than 12Kw, you could wire AC-OUT 1 to the consumer unit. Presume, though, that you heat pump will be a big factor here. If you provide more detail then people on here can help - i.e. inverter, batteries, heat pump power need, daily consumption, that kind of thing.

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Richard Weir avatar image
Richard Weir answered ·

Thanks for those details, very helpful. I have a 48/5000/70 amp Multiplus 2 which calculates as about 16kw. So I could put the whole house on the inverter and will consider that. Like you say the main draw is the HP so I think I'll connect that to AC OUT 1 as a first mod.

my next problem is that the battery is now not discharging. its stuck on passthru and i cant seem to mod any of the VE Config parameters to get it back to feeding into the system - help would be appreciated. thanks so far

https://vrm.victronenergy.com/installation/221360/share/098d9b04


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Jason - UK avatar image Jason - UK commented ·

@Richard Weir Check you have the rocker switch underneath the unit on the right hand side set to inverter chager, not charging only.


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michaelvh avatar image michaelvh commented ·
How did you arrive at 16kw?? The MP2 48/5000/70 has a continuous output of 4kw with peak 9kw. The 70A is for the DC side for charging batteries at 48V, not on the AC site at 240V.
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Richard Weir avatar image
Richard Weir answered ·

a94d9235-b002-43d6-bebc-9a4fb1d29a6f.pngc813fb52-7650-4873-a2d4-fdbfe48d65ad.jpeg

Here is my inverter

And the dashboard


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ajmacleod avatar image
ajmacleod answered ·

Which ESS mode are you using, and what is your minimum SOC set to? Also, what Grid Metering do you have?

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Richard Weir avatar image
Richard Weir answered ·

I’m using Optimised with BatteryLife. SOC set to 10%. I’m just using my Octopus smart meter.

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ajmacleod avatar image ajmacleod commented ·
It looks like it's been working correctly since Saturday evening? (using VRM link above) - Discharging down to 10% about midnight, recharging through the night til 4AM then discharging again?
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johnone avatar image
johnone answered ·

Just to note there is no requirement to use a grid meter, as per image below. Have to say, am intrigued by the size of the earth cable in your pic above?

w0h4edau8sk0ji4d.png


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ponzoa avatar image
ponzoa answered ·

If you want loads on the AC IN side of the Multi to consume battery power then you DO need a meter to speak with the system. In a single phase, you can use a ET112. Without that, it considers any power taken from the AC IN side as power fed to the grid so stops that power from exiting the Multi.

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ajmacleod avatar image ajmacleod commented ·
Unless you set a negative grid setpoint of course, but that's a pretty blunt instrument. The reason I asked about metering was that it's possible to have more than one registered but the system configured to use the "wrong" one and hence not self-consuming (guess how I know!)
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Richard Weir avatar image
Richard Weir answered ·

3e7238bc-36e5-4efc-b6b9-4ccdf281682f.jpeg
Here is my system.




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