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jamesreeve avatar image
jamesreeve asked

Multiplus II as a home battery for load shifting.

Hi all,

I'm looking for a detailed tutorial or guide to setting up a Multiplus (Installation and configuration) with batteries for a home battery system. I've got a MP 48/5000 and a Cerbo in the UK.

I've a DIY battery (14.5kWh 16s1p) with JBD BMS also ready to go.

Is there a detailed wiring diagram for the MP to mains connection, I know it should be simple (Three wires) but there is a number of AC connections on the MPII, so want to make sure it's right (I'll be using an electrician to do the final termination and test). There is no requirement for UPS or blackout power at this point.

My goal is to soak up spare solar from my existing 4kw system (Solar Edge HDWave), and then use that power during the evening to avoid at least peak rate import. I'm on Octopus Flux but not yet really making the most of this until the inverter and batteries are up and running.

I know I'll need a CT clamp on the mains incomer, I already have a shelly EM1 on the live leg so hoping I can use that to feed the Cerbo (Possibly via HomeAssistant).

Any help, or a tutorial suggestion would be brilliant, thanks Mark

balanced ac-load
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4 Answers
gazza avatar image
gazza answered ·

Pretty much everything you need to know is in this publication, or links provided within. After checking out the possibilities you can sort out a schematic for your purpose to give to your electrician.
https://www.victronenergy.com/media/pg/Energy_Storage_System/en/ess-introduction---features.html

For more specific questions it's good to do a search for your setup. For example there may be something here regarding your meter?
https://community.victronenergy.com/questions/142851/shelly-em-single-phase-with-venus-os.html

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iammotorhomeless avatar image
iammotorhomeless answered ·

@Jamesreeve I know the clamps are cheap... but the ET112 is so much better

just to be clear on what you have, and what you want
are you going to wire the MP II 48/5000 as a passthrough invertor... to run your loads
or are you just going to charge the battery with excess and let it feed back later

I have a MP48/1600 that cascades off my main system.
I just have one power cable, the AC1 conected to it. I use node red and MQTT to charge and discharge it by simply adjusting the grid set point,
and it dumps between 4 and 7 pm, I am also on Octopus Flux

would look something like this

1698606641059.png


1698606641059.png (56.9 KiB)
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iammotorhomeless avatar image iammotorhomeless commented ·

@Jamesreeve

sorry I missed your question...
my main system is a pair of MP II 48/5000 with it's own Cerbo GX

so the cascading system, takes it's lead from the main one.
with mine, the main system sends data to the MQTT broker and the smaller one gets that data.
I use the Battery Power in watts and the SoC of the main battery to tell the small one when to charge or discharge.

1698707324517.pngbut the other option would be to just have your meter and set the grid point based on it.


so my simple solution would be...
you could just use the schedualed charge level in the ESS settings to charge over night
and set the "grid set-point" to a negative amount when ever the Shelly EM1 regesters a usage draw, based on the house usage. Or to charge if you have excess power from solar.
I think the Shelly EM can connect directly to your Wi-Fi network, so you can access it easy enough in node red
"in my flow, I have a fail-safe, that just injects a zero value every six minutes, incase the MQTT or your Shelley loses signal. so the grid point goes back to normal"
having a ET112 hard wire to your Cerbo would reduce that risk, and might be more accurate at holding the grid point.


my 48/1600, has a max watts of 1300w, so less than 6 amps. I just plug it into a 13amp socket.
your 48/5000 is going to be closer to 20 amps. so either hard wire it in to a 32Amp braker
or if you want to be able to fully isolate it. get the electrician to add a 32Amp socket to plug it into.

con-board.jpgthen, as long as you keep the main house load below 4000w, the 48/5000 will cover it. without using any power from the grid.


this is just one solution that I found easiest to set-up... for me
if you need more.. please add @IamMotorHomeless to your question so I see it :)

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1698707324517.png (50.7 KiB)
mrjj avatar image mrjj commented ·
Hi, what is exactly things I need to add to what I got from new boxed Multiplus II GX ? Nodered, octopus, et112 those does not tell anything to me yet. I found it pretty complicated to setup to such a simple use as presented here. What I want is simply, charge daytime with surplus energy (=current meter in external energy meter show minus watts) and discharge when allowed by external relay or time schedule. Discharge amout based on watts used in external energy meter. Shelly Pro 3EM is external energy meter. One for Grid connection = whole total usage and there is second Shelly Pro 3EM just for solar inverter connection.

This Multiplus seems to be tailored for off grid usage in boats and cottages with random ongrid connection, mainly powered by solar and generator.

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nickdb avatar image nickdb ♦♦ mrjj commented ·
If you aren't familiar with the Victron ecosystem, I would encourage you to consult an experienced supplier for guidance. It takes a fair amount of knowledge and experience to configure these systems, they were not intended for end-consumer setup.

There is a lot of free training at professional.victronenergy.com that can help get you up to speed, and the products are quite well documented.

Without having the basics of how the system works, more advanced topics like this can be overwhelming. Dynamic ESS is designed for this use case and integrating into variable cost tarrifs.

Victron has a massive install base of small to large systems, grid-tied or off-grid for exactly these type of use cases. You just need the necessary background and training to configure it. The community, as per its terms, generally does not encourage design topics, but there is a lot of information available via search etc.

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jamesreeve avatar image
jamesreeve answered ·

Hi, your system looks exactly what I'm after, I'll be using NodeRed to determine when to charge and when to discharge. The idea is to never export from the batteries but to minimise import at all times with the exception of winter when there won't be enough solar to cover the daily load; currently about 10-12kwh per day, so will be charging on the cheap rate overnight where the following day's solar forecast is not going to be enough. Key is to avoid import during the 4pm to 7pm time slot..

So presumably you connected AC1 to your house system? What sensor did you use for detecting import/export? I've currently got a Shelly EM1 on the DNO Live next to the meter...?

Can you share some of your settings with me?

I'll be getting the electrician to connect the MPII AC1 to it's own breaker in the house; beyond that, its all up to me.


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gazza avatar image gazza commented ·
Just to be clear. When you say “AC1” you mean AC IN right? The schematic as shown by @IamMotorHomeless is only connected toAC IN. This is sometimes referred to as a parallel system with AC IN, being a bi-directional flow when ESS assistant is installed.
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jamesreeve avatar image jamesreeve gazza commented ·

Hi, I guess yes... lol

AC in presumably is two way, as in it will consume from AC IN to charge batteries, and will export energy when programmed too?


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gazza avatar image gazza jamesreeve commented ·
Yes. In the way the schematic is shown above it is effectively a grid tied inverter supplied from a battery.
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jamesreeve avatar image jamesreeve gazza commented ·
Thanks for the clarity.
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daniel-feist avatar image daniel-feist commented ·
Enable ESS and configure a scheduled overnight charge and that's about all you need config-wise unless you want to force-export between 4-7 pm.

Personally, I moved off of Flux a month ago, as it just doesn't make sense in the winter given other tariffs have better overnight rates.

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jamesreeve avatar image jamesreeve daniel-feist commented ·
What did you move to?
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daniel-feist avatar image daniel-feist jamesreeve commented ·

Octopus Intelligent for import (7.5p 11.30 pm->5.30 am). Octopus Outgoing for export (15p all the time).

If you don't have an EV you can't use intelligent, but it's still worth considering "Go" during the winter given 8p from 12.30-4.30am overnight is a lot better than Flux.

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iammotorhomeless avatar image iammotorhomeless daniel-feist commented ·
I guess it all depends on how much you import.


my system has only been up for 6 months, but I have not even come close to importing anything yet since it was switched on.
and I am still exporting, not every day, but most days we hit over 90% and two or three days a week we export something

would be differant if we had an EV, but it's still on the wish list
and it might be differant next month


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slartybart avatar image
slartybart answered ·

Easiest configuration is to set the Multiplus in ‘single leg’ ie just connect the Ac-in to the consumer unit. It’s bi-directional, as someone has already said. The live goes to a suitably rated MCB, the neutral goes to the neutral bar and the earth goes to the MET. Wiring in the et112 before the inverter mcb measures grid and the multiplus measures its own output and balances the two. In my consumer unit I have a main breaker for the mains. That goes into the et112 through the bottom busbar on the right. Then a second live busbar goes across from the left hand terminal to the incoming live MCB from the inverter and then on to feed the circuits. As far as configuring charging etc……in ESS: schedule charging with 100% SOC to force charge and grid usage. 20% with PV only to use grid and PV to cover loads, for times when the prices don’t make sense to use the battery. And lastly 20% SOC with PV and battery to use the battery and panels to cover the loads during expensive grid times, 4 til 7 usually with Agile Octopus. One trick, if using 25mm tails from the Multiplus, is to put an 8mm lug on the end, cut the lug hole into a fork and use two adjacent slots on the neutral bar. You won’t get a 25mm cable into the small holes of the neutral bar. Best of luck!

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