question

anybody able to assist?

i think , looking at it, the CT clamp needs to be on the inside of AC1 out, when in micro grid mode.

but that might be the best place for it (where i've drawn it), when the 'systems' are connected to the grid. which is possible to do with an automatic switch and relay.

but i might be completely wrong, let me know what you think

in case somebody else has this query or similar, i've done exactly as i've described above. i've set out to make my 'fairly standard' solar installation from a national company (which is heavily grid dependent) work with a multiplus ii 8000va. the multiplus offers the ability to (in the event of a grid failure) still run the whole has house (obviously with fewer devices switched on) in a normal usual way of life. whereas the solar installation would just be useless without the grid.

it's worked so far. i did it very cautiously, lots of tests in the build up, slowly slowly catchy monkey. but ultimately as we approached the end of all the wiring and software updates etc, we had to do a switchover from grid to grid-in-series-with-the-multiplus. and it just worked! i then switched on the luxpower (i moved the CT clip as described earlier in the year) and it just worked, as normal, just trying to keep the it's CT clamp reading to 0w..

here's an outline schematic

here's a slightly more detailed schematic of what i've done.

the bit of circuitry in red isn't accurately displayed. it consists of a 125a switchover switch. it's purpose is to switchover (carefully) from the grid being in series with the multiplus ii ( as above ), back to a 'normal' state of the house being connected directly to the grid. - purely for fast recovery if the multiplus ever needs maintenance/fails. we can quickly isolate the multiplus's inputs and outputs, (we accept we have to lose power to the house momentarily), and go back to the grid as per normal.

the orange spots are showing where the CT clamp needs to be moved to and from if the above risk scenario needs to be executed/undone.

and yes, it works. i'm very pleased with Victron. i'm currently trying to interface to it from Home Assistant. i've already been interfaced with the luxpower for a long time, so it can predict when to fill up the batteries based on tomorrow's weather forecasts on the off peak tariff.

i've got 3 x Pylontech us2000c on the original luxpower (could be any grid tied inverter) collecting solar pv all day. and it just treats the multiplus as 'the grid' - it knows not of its existence.

i've got 4 x us2000c and 1 x us3000c battery connected to the multiplus ii, via a lynx distributor, and cerbo gx. it is idle most of the day until the luxpower runs out of energy. it kicks in when needed acting as 'the grid' up to 6400w. when it runs out of battery energy or can't invert enough to satisfy the loads of the house, it uses the actual grid.

i hope this helps somebody extend their standard grid-tied solar pv installation some day.

Thanks for sharing. This is exactly what I'd also like to do and had a few questions:

1. With this setup when there is excess solar being produced by the luxpower, can this excess be feed back to the grid?
2. When the grid is down, and there is excess solar being generated, what does the luxpower do.
3. Would you be so kind and confirm the connection points on the multi i.e. Grid to AC IN, LuxPower + critical loads to AC OUT1?
4. Is there a CT or meter installed for the Multi?

hi,

finally, somebody replies. i thought this article had been blacklisted for being from the dark side of the spectrum.

1. i was wondering the same, before hand.

the multiplus stores any excess coming from the luxpower into its batteries. so you lose some energy in the DC-to-AC and AC-to-DC. but still, for me, its better to have 80% of something, than selling it to the grid, because we do use it all. when the multiplus' batteries are full, and the luxpower batteries are full and still producing solar, then it goes out to the grid via the multiplus. all batteries are full at that point. (actually the mulitplus' batteries at 90% full, cant absorb as fast the energy, so if it's a huge amount then some goes into the batteries and some goes to the grid at this point, but you dont want to charge above 90% anyway too often (ref general lithium battery rules))

2. if grid goes down the luxpower carries on as normal because it 'sees' the Multiplus' micro grid as a standard 50hz grid (UK), it knows not of its existence. But i detect that the grid is down through modbus (on the multiplus), and if the batteries are nearing capacity at any point thereafter then a) turn off the luxpower/standby it. and b) turn on the immersion heater, to get the batteries down. c) send me an alert, so i can monitor it.

never happened yet though. but the risk is there.

3. it's pretty much as the diagram.

Grid to AC-IN.

L1 to critical loads. via my usual consumer units.

Luxpower (is as the "professionals" installed it), connected to the tails cables in the henley blocks. it goes henley blocks, to the (installers) mini consumer unit, to AC isolator, to solar meter (which they have to install for it to be compliant with MCS, (waste of space)). and the henley blocks are on L1, critical loads, which is just my house and garage henley blocks as it was before.

L2 to EV chargers.

4. there's no need for a CT clamp or a meter. if you read everything carefully, you don't need it because it's in series, it detects everything itself, it sort of has to detect it.

A lot of the example projects online, and standard setup guides, keep talking about the meter option or CT option, but i think it's something to do with saving money and trying to buy the cheapest set of kit for your barge or van (without the cerbo gx) and get away with it as a standalone inverter charger.... i think.....

but logic told me the multiplus ii connected in series just wouldn't need it if i bought it with the premium cerbo gx (which is just an expensive raspberry pi 4 by the way victron!), because the cerbo gx can extract that from the multiplus ii and present it to me/home assistant.

So Victron is the better product, for me, i would never buy luxpower again. my only complaint is victron needs to build bigger Solar Charger MPPT, capable of 500Vdc like the MPPT's inside the luxpower hybrid. when they do that, AND the luxpower breaks some day, i'll just replace luxpower with Victron Solar MPPT's. rant over.

on reflection i didn't need to buy the 8000va model, i could have bought the 5000va multiplus ii. and with my luxpower 3kw inverter (ref the rule of Factor 1.0 rule), i strongly suspect it would have been fine. we can actually go off grid up to 6.6kw + 3kw = 9.6kw now if we want to. but we don't really need to turn on so much stuff in parallel ever. so i could have saved some money there, and it would have been lighter to get up on my wall too!!. hopefully a larger multiplus ii will pay off in the long run, if it lasts longer due to its over-size and under-use.

it's the turn of wind turbine project next...

hope this helps

Thanks so much for the detailed response. I'm in the UK as well and have a 5kw Givenergy inverter and 2x8.2kwh battery setup in exactly the same way (grid parallel) as you describe. I'm planning to add Victron Multi + pylontech batteries to this setup in order to increase the peak power usage in the house, which with my current setup is only 2.5kwp in no solar (winter) conditions. So if I understand correctly, the meter tails from the electricity meter were disconnected from the henley blocks and connected to Victron Multiplus ACIN and the AC OUT1 was connected to the henley blocks. This makes sense now, so minimal rewiring, which is excellent!

Regarding point 2, when there is excess solar and batteries are fully charged, do you manually put the luxpower inverter on standby or is this automatically done via Victron shifting it's output frequency, or some other way? Also, how have you setup the alert when grid is down, is this via node-red?

One other request, would you be willing to pass on the details of the electrician/company that added the Victron to your setup. I would love to approach them and get a quote given they have experience of doing exactly the same setup.

point 2

i dont think the luxpower can understand frequency shifting. does givenergy? but i set it automatically to standby, using Home Assistant which talks to the luxpower over the wifi. but i also turn on the immersion heater, and set it to send me an alert. again via home assistant. just to manage that small risk.

i've wired it all myself. i just took my time, and connect brown to brown and blue to blue, and follow it through. and read the helpful guides from Victron multiplus, and apply what it says to your setup and design.

just take the plunge, buy the multiplus ii, get the batteries, buy some tails, get it on the wall, get the batteries plugged in, configure it offline in a testbench environment, run some tails to its AC-IN, run a 2kw heater on the AC-OUT1. test it inverts and charges the batteries. then the next day plug it in to your house. you just have to build it up piece by piece, and switchover.

it's easier than you think.

Thanks for that information. I can't find any information anywhere online if the givenergy hybrid inverter can understand frequency shifting. So I'm guessing it doesn't understand it. I might try the same as you via homeassistant and can control the inverter and the eddi that manages my immersion heater.

One additional question - do we need DNO approval to add an additional inverter (and battery storage) since i would be technically going from 5kWp to 8kWp by adding the Victron multi?

probably..... by law.

by the laws of logic..... no. because you set your victron to never push out more than x Kw . and your solar panels will never push out more than they've been DNO'd for.

so it'll never push out to the grid more than the DNO amount.

depends if you like spending money for illogical reasons.

Thanks @mattw and @Jason - UK. Really appreciate your answers.

I read a few posts that the Multiplus II 48/8000 is not yet G99 certified for use in the UK. I looked at the ENA website and could not find an entry. Does this mean it can be installed but will require an anti-islanding device fitted or can it be installed without one? Or does it mean this inverter can’t be installed at all?

that's all above my pay grade i'm afraid. mine's installed and working. it wont feed the grid in the event of power failure, due to other controls in place. if a = x and b = x then a = b

OK, so I've decided to go for it. I'm planning to go for the Multiplus II 48/8000 given my existing solar PV is a 5kWp GivEnergy system, in order to satisfy the Factor 1.0 rule. I will also be going with 4 Pylontech US5000 batteries. I've been preparing a list of items to purchase and realised that I have a few more questions:

1. When connecting the AC IN of the multi to the grid, is there a need to connect it via 63A RCCB and a 63A MCB or would it be ok to just connect via a 63A MCB? @Jason - UK in your electrical schematic on your VRM site, I see you are using just a 63A MCB, but other posts suggest both an RCCB and MCB.
2. If a 63A RCCB is required, what should its sensitivity be - 30mA or 100mA, in order to provide selectivity?
3. The manual for the multi recommends using 2x 50mm2 DC cables to the batteries with a 300A fuse. I wanted to check how to physically make this connection. Could I connect the 2x 50mm2 cables to the lynx distributor with 2x 150A mega fuses or does this need 2x 150A ANL fuses in their respective holders.
4. For the Multiplus II 48/8000, I wanted to confirm that it is possible to set the country grid code for UK in VEConfigure since it is not listed on the ENA website as I would want to feed excess PV to the grid.

hi, sorry, it doesnt notify me if there's a reply for some reason. unless you mention my username.

1. mine goes from smart meter, to henley blocks, to Victron MultiPlus II AC IN. the multiplus is a big boy, it's designed to play with the grid directly. and it's rated 100amps, so why limit it with 63a. and you dont want it tripping. the multiplus is not an end user device, like a kettle. it's on the same device group list as smart meter, or a consumer unit. you dont protect the consumer unit or the smart meter with another consumer unit full of 63a MCB RCCB, do you?

2. n.a

3. ebay says i bought these:

and some of these

they barely get luke warm at full charging and discharging, so they're good.

4. yes UK is definitely there. read it carefully when doing that, read a few guides. and you can set the multiplus to never export to grid more than x000 watts / or amps. can't remember. i just kept everything well under spec.

i chose US2000C (and by accident i bought a US3000C) mainly because they are lighter to lift and maintain, on occasion. the US5000C is very heavy.

mind you , so is the multiplus 8000va, as mentioned.

Good for you! getting going. soon be there.

@Roshan wrote

<

• When connecting the AC IN of the multi to the grid, is there a need to connect it via 63A RCCB and a 63A MCB or would it be ok to just connect via a 63A MCB? @Jason - UK in your electrical schematic on your VRM site, I see you are using just a 63A MCB, but other posts suggest both an RCCB and MCB.
• If a 63A RCCB is required, what should its sensitivity be - 30mA or 100mA, in order to provide selectivity?

>

In the UK to comply with the IET Code of Practice (which is incorporated in the Building Regs and MCS certification) the Multi needs to be connected via a separate RCD (not shared with any other loads), 80A/100mA is probably the right rating as this will give some discrimination, though somewhere else I have seen that 30mA is preferred. Don't know the reasoning behind that, assuming the load circuits are properly protected by their own 30mA RCD(s).

Thanks for sharing that info @mattw and @sharpener. Really appreciate it, as I get my head around the Victron gear, wiring, etc.

Hi

Im planning to make same as my Luxpower is simply to small for my needs .

1. Can you tell me what about charging batteries from the grid looks like ?

2. Can you show me your Cerbo screen how it works and looks like ?

Thank you