Victron Multiplus ii Installation | Complete Wiring For Off Grid

Solar and Electrical Equipment:
conduit as needed
Hardie backer board

Parts list:
1 1/2" conduit
thread protectors
Tools below ↓↓↓↓↓

Tools Used for Our Solar Install:

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[johnhuntley]

Electrical Inspector here...because power originates in your solar shed, that is your service panel. The one in the barn is a sub panel. Neutral and grounding bars need to be bonded in the solar shed, and that panel needs a grounding conductor and service grounding rod or plate. The sub panel in the barn requires separation of Neutral and ground buss bars. Because they are separate buildings a grounding conductor and rod or plate are required at the barn as well.
Good video and explanation. Cheers

[petersamios]

First off - thanks for the information about your setup. A few comments: I'd put ferules on all of the wires that don't have lugs. For those with lugs, I'd make sure that all of the copper strands are encased in heat shrink. And I'd try to make the insides of those boxes as neat as possible. Remembering that a pinhole in the insulation can cause arcing.

[rockygrindstaff]

You are fantastic at explaining and keeping it simple

[lucasthijssen]

Hello from Italy! 🇮🇹

Great video, very interesting, and thanks for sharing! I'm about to set up the same system as you. I checked the wiring diagram and have some observations regarding safety and functionality, as well as a few questions:
The SPD should be connected by taking the positive and negative directly from the input of the MCB, not from its output. This is a regulation in my country for the following reasons: it protects everything downstream, including the MCB itself. Also, as it is now, if the MCB trips, you would be left unprotected since the SPD is powered from the MCB’s output.
By the way in a solar power system with panels located far from the house, it is advisable to install Surge Protective Devices (SPD) both in the combiner box near the panels and at the house entrance (where the inverters are located). This dual protection is not redundant but serves important safety purposes.
Reasons for installing SPDs in both locations:
- Cable length between panels and inverter: if the distance exceeds 10 meters, it is recommended to install an SPD near the panels and another near the inverter. This is because, with long cables, surges may attenuate along the way, making a single SPD less effective.
- Optimal inverter protection: the inverter is highly sensitive to voltage surges. An SPD at the house entrance protects the inverter from surges originating from the panels, while the SPD in the combiner box protects the solar modules and limits the spread of surges along the cables.

By installing SPDs at both points, you ensure comprehensive system protection, safeguarding critical components and complying with industry standards.
Did you also have the SPD on the AC side? Type 2 AC SPD If you want to protect the inverter and connected devices from induced overvoltages. Or Type 1+2 AC SPD If you are in a high-risk lightning area or have a generator with direct grounding.
In my system I will have a heat pump at a certain distance from the inverters and I will have an additional SPD (Type 2 AC) in order to protect the heat pump from transient overvoltages caused by switching operations or lightning.

I understand that you are using the Nader MCB only as a switch because each device is already protected by a fuse inside the Lynx Distributor, correct?
I also understand that the battery bus bars are there for future system expansion, otherwise there would no need to install them.
By the way the connection you made will have a preferred path on the left battery because it offers less resistance, a better connection would be connecting the negative terminal of the right battery (instead of the left battery as it is now) to the negative bus bar.

Did you ground both Multiplus inverters since they also have a metal frame? I am not sure about the lynx but if it has a metal frame too you should ground it as well.

At 12:55, you mention bonding neutral to ground in the main panel. Could you explain how you do this? I thought the Multiplus, when in off-grid mode, handles this bonding automatically via its internal relay. You should avoid two bonding point, beware!
You did not mention anything about your grounding system which is really important. Actually I see some problems in your set up (one point is the SPD connection). I suppose you have a rod or multiple connected rods in the earth, which should be connected to the ground bar, which must be the only single grounding point (called the main equipotential bonding point) which serves as the single reference point for all grounding connections.

Why is a single main grounding bar better?
- Avoiding ground loops: If multiple independent grounding bars are interconnected (as in your case), potential differences may occur, leading to stray currents, interference, or malfunctioning of RCDs.
- Easier management and maintenance: with a single reference point, it is easier to monitor grounding quality, measure resistance, and troubleshoot any issues.
- Uniform distribution of leakage currents: a single equipotential node ensures that fault currents discharge effectively, preventing overloads in specific sections of the grounding system.
- Efficient fault protection - a single grounding node ensures that, in case of a fault, leakage currents can quickly find a safe path to ground, allowing protection devices (e.g., RCDs) to operate correctly.
My planned grounding setup:
* Main grounding bar (connected to 2 or 3 ground rods, either daisy or loop chained)
* Equipotential bonding with metallic pipes, structures, and other conductive elements
* SPD units connected directly to the main grounding bar
* Neutral-to-ground connection (still in doubt wether to let only the MultiPlus Master handle this bonding or make a fixed connection in the main grounding bar)
Does this setup make sense to you?
Thanks again, and I look forward to your comments! 😊

[mondotv]

Looking good. Couple of questions/observations. Don't understand why you included the additional bus bars between the batteries and the Lynx distributor when the Lynx is basically a fused bus bar? And I believe it's best practice to turn on the AC side of the Multiplus 2 before the DC as that pre-charges the caps for you. Also I think the Victron manual mentions using ferrules on the AC connection side. Good work leaving the looped conductor on the AC side - definitely necessary and often overlooked.

[Liberator]

Hi thank you for for the very informative video I am working on my own solar project and really appreciate your thorough video. I am wondering though, why did you use a bus bar between your batteries and the Lynx distributor, isn’t that your bus bar?

[norbertkajubiee]

7:03 the fuse is not to bridge positive 2 negative... its just between the cabe & positive bus bur

[akhenatn]

8:00 Hi, a question, it is ok that the negative pole in multiplus ii is missing a plate but positive has it??, i'm preparing to install my multiplus and just noticed that...

[RenewableWise]

I believe you should have a wire from the negative of the battery bank to that ground bus bar in your subpanel, this would serve as your DC system bonding jumper. That battery bank is more than 50 Volts, if the positive conductor from the bank touches the case of one of the inverter, you need to have an effective path to clear the fault. This would be from case, to the ground bus bar (through the ac out ground wire), back to the battery.

[roaringpitty]

Happy thanksgiving, I’m completely off grid and would love to know your solution for not using the AC input. I’ve got the 230 48v 10, 000w multiplus ii. Can’t even get it to turn on to connect to computer to turn on “ignore AC input”

[anaxiosesti]

are those 3000kva better choice than one 5000 ? because in maths 2x 48 3000 cost as much as a GX 5000 70/50 !! did you test their surge capability ? if i remember it says 5500 for several seconds.. if yes then they are quite good!!!!

[seanbyrne-smith]

Neutral in Australia is black and positive cables are generally red or with 3 phase red white and blue

[sjwolf]

what size wire and flex conduit size are you using? Is that seal tight? What connector coupling?? It looks great. Thanks

[racingtogreen]

It appears that you are, at least for the moment, sold on Victron. I've just completed an Epever to Victron upgrade on our solar powered shed, but initial performance results, and ease of use increases doesn't appear, so far, worth the additional cost. We're now moving on to a 3.6kw install solely to charge our Ford Lightning, and run the garage mini-split, and we're hyper focused on ROI, and breakeven point with 10kw of lifepo4 batteries. I had considered a split phase with Victron, but at the moment, from a cost conscious standpoint, I think we'll be going with a hybrid inverter from MPP. Idle usage could play into that ultimate choice, as most of the hybrids run over 100 watts idle consumption.

[DanGavern]

Thank you for this video! When connecting ferrules, I followed your advice and sliced the plastic shroudand made sure the wire makes contact with the ferrule metal tip.im still not getting the Victron to function though. Any thoughts? TIA!

[jacquesdutron]

Thx a lot for all your efforts and tips. However one company and one company only made the solar powerful, affordable and so easy to install, a 15 yo can do it. It's none other than Signature solar. I don't know why I'll get any other system than the EG4 18K-PV plus 2 Powerpro WallMount and sleep peacefully knowing I got one of the best in the market. These are also close enough (Solark 15K & Schneider XW pro) with EG4 18K-PV I don't need a charge controller, no combiner box, no disconnect. (I'll get a solar isolator and might get a T-class fuse) that's it folks.

[mnjG]

I love how you explain all your different solar installs. Still trying to decide for whole house 200 amp panel do I want the EG 18k or SolArk. Leaning EG because the new chargeverter levels the playing field for me. As always, GREAT JOB!

[timcastle]

Did you change over from EG4 to victron?

[pierregalin]

What gauge are the DC wires going to the inverter? The instructions for the Multiplus II say to use a 400A fuse, and 2x AWG 1/0 between 0 and 5m or 2x AWG 2/0 between 5 and 10m. I don't understand .... why 2x cables per terminal? I also see some folks using 4/0, which, isn't rated for 400A. Confused, can someone clarify?

[jacquesdutron]

Thx a lot for all your efforts. With hybrid systems like Solark 15K or EG4 18K-PV, no one will be buying charge controllers. They eliminated many devices, components and wiring. Sorry, for victron and the likes.