New inverter installation, connection to boat's AC panel, shore power connection

[Nor]

Originally Posted by Madehn

I have a high amperage rotary switch that allows me to select inverter 1 inverter2 shore or generator for AC power. True I cannot combine two sources but I really don’t want or need to. It is simple and means I don’t have a single point of failure for my AC power. ( I can turn both chargers on for 280 amps of charging if I want to. Simple and robust.

That's also an interesting way of doing it. The main reason I'd like to connect shore power to the inverter is so that we can still use solar when in a marina, to save on the electricity bill and not waste the solar. But a simple setup would also be good.

[hjohnson]

Originally Posted by sailingharry

You must make absolutely certain that the white wire on the shore power run never connects to the white wire bus in the boat distribution system. If you do, you will trip the new Marina power systems when you plug in. What happens is the inverter when running connects the neutral and ground together. When you plug into shore power that connection trips the leakage breakers.

That’s not a problem with the Victron units as they have a ground bonding relay. When it closes the relay to connect the shore power, it opens the bonding relay that connects neutral to protective earth.

What happens when you connect shore power is that the victron will sit there for a bit and analyze the incoming shore power. It will then synchronize the output both in terms of phase and voltage, before throwing the relays to make the connection. It’s really well done.

[hjohnson]

So when we did the electrical upgrade on my boat, we took the opportunity to modernize our AC system on the boat.

Immediately after the shore power inlet, we installed a galvanic isolator on the Protective Earth. This has dramatically slowed how quickly we go through zincs on our shaft, which is a big win. We also installed a 30A ELCI breaker adjacent to the shore power inlet. it’s in a small DIN rail enclosure just inside our lazarette, along with indicator lights for reverse polarity and power on. We operate that breaker before disconnecting the power, and after attaching power.

From there, it runs directly to our multiplus. The output of our multiplus then goes into another 30A breaker. This is because with the power boost functionality, you could theoretically get 50A out from the inverter/charger, but we didn’t want to size the wiring for that.

From that breaker, The finally goes to our small 3 circuit distribution panel. One circuit for the hot water tank, one for the starboard outlets, and the third for the port outlets.

Our PE is connected to our DC negative, which is in turn connected to the ocean via our engine/shaft/prop. When away from the dock, the multiplus bonds the neutral to PE automatically.

All in all, it works reliably, and I consider it to be quite safe. We now basically never shut off the inverter, and our AC power just magically keeps working. We just tend to breaker off the hot water tank, unless we have a relatively full battery, and know we’ll be back at a dock in short order. It’s really really nice to be able to do dishes normally.

But yeah, for a 27’ boat, it’s pure indulgence, and I absolutely love it.

[s/v Jedi]

Check out the two attached reference diagrams I made for 230V/50Hz installations. You are somewhere in between the two.

So in the basic one there’s the isolation transformer. The Victron 3.6kW supports the full load of a 16A shore power connection and it is the very best spent money for the safety of the boat, the crew and people (swimming) around the boat.

Just make sure it is connected exactly like shown, i.e. the ground wire from shore is NOT connected to the boat ground. Use a multimeter to verify that there is no connection between the ground wire from shore and the ground busbar on the boat.

The diagram shows two outputs, where one is always on when the inverter is enabled and the other only when shore power is available (like for a water heater, air conditioner etc.) You can simply leave the second output out.

The second, advanced diagram adds many things: a genset which you have. Yes, use the switch unless your genset has a cord that physically attaches to the shore power inlet, like done for a Honda portable.

It also introduces the use of busses. The input bus and up to three output busses. It shows a bypass breaker to a separate output bus which allows operation without even an inverter/charger installed.

It shows multiple inverter/chargers in parallel or autonomous use which is great for redundancy, high power levels and also frequency conversion when visiting 60Hz land. You can use just one, or install four etc.

Note the bus selector switch in the distribution panel. Of course you can hardwire a jumper to one of the output busses but I have seen damage resulting from a quick mistake with a jumper, which is impossible with the switch.

[Traumerei]

You’re getting some good advice from others.

On my installation. The shore power goes first to galvanic isolator. Then to the Victron inverter/charger.

The mother board in the Victron know the source of power for the boat in terms of charging.

On my boat all ac runs through the inverter if the inverter is on. Some installations require a selector switch where you choose between shore power and inverter.

There is an excellent source of help and advice on Facebook in the Victron forum.

Best of luck with your install. Be sure to follow up with what you do.

[Andrew Lippman]

There are lots of ins and outs to 110VAC wiring, especially with respect to isolation and grounding. You really have to be an electrician, making it up as you go is not a path to success and meeting code. For example, in general a power source connects neutral to PE. Thus the isolation transformer connects the two on the secondary, since it is a power source.

An inverter is also a power source, so now where is the connection? Inverter/chargers have settings to manage this correctly, but you need to know what you are doing to be safe.

[ccanupii]

First, are you using a multiplus or quattro? Quattro uses an automatic transfer switch. Make sure you read the manual carefully especially on supply wire size. These things require dual cabke connections. Best case is to use a power distributor and fuse properly. Your shore power runs to the inverter. The white wire IS NOT THE EARTH in USA. Look at the victron site to get some ideas of the system requirements. Draw your system up and consult with a reputable marine electric engineer well versed in Victron. They will usually answer your questions and offer advise for free if you buy from them. These things can get complex and expensive but it has to be done right because if not, it could be disastrous. Again, if you are unsure or not comfortable, seek professional assistance.

[sailingharry]

Originally Posted by hjohnson

That’s not a problem with the Victron units as they have a ground bonding relay. When it closes the relay to connect the shore power, it opens the bonding relay that connects neutral to protective earth.

What happens when you connect shore power is that the victron will sit there for a bit and analyze the incoming shore power. It will then synchronize the output both in terms of phase and voltage, before throwing the relays to make the connection. It’s really well done.

My problem was almost 2 years ago, so I forget the details. However, when I first installed my inverter (and modified the 110V routing scheme so shore power went "through" the inverter -- as built, the 110V panel was on an A/B switch, either shore power with a feed to the inverter as a charger, or inverter power), it would trip shore power 100% of the time, instantly. I then realized the white on shore power side was on the same bus as the white on the ship side of the inverter. I split it (so shore and ship white were no longer connected) and it solved the problem.


I will defer to your understanding of what happens inside. I don't really care what the problem actually was, as it works now!

[Rigdaddy]

Originally Posted by Nor

That's also an interesting way of doing it. The main reason I'd like to connect shore power to the inverter is so that we can still use solar when in a marina, to save on the electricity bill and not waste the solar. But a simple setup would also be good.

I also have a rotary switch separating my AC sources and have no problem using solar while at a marina.

[Nor]

Originally Posted by ccanupii

First, are you using a multiplus or quattro? Quattro uses an automatic transfer switch. Make sure you read the manual carefully especially on supply wire size. These things require dual cabke connections. Best case is to use a power distributor and fuse properly. Your shore power runs to the inverter. The white wire IS NOT THE EARTH in USA. Look at the victron site to get some ideas of the system requirements. Draw your system up and consult with a reputable marine electric engineer well versed in Victron. They will usually answer your questions and offer advise for free if you buy from them. These things can get complex and expensive but it has to be done right because if not, it could be disastrous. Again, if you are unsure or not comfortable, seek professional assistance.

I'll use a multi rs, it's a inverter charger (with solar input). I'll add a switch to swrich between shore and generator. I'll ground the inverter to the boat, will do more research on this, it's not clear to me where I should connect the invert chassis.
I'm not in the US, I'm on 230v.

[Nor]

I've made a drawing. This is 230V.

The 32A going to the galley and 32A going to the AC panel can not be maxed out at the same time, the inverter can't deliver that much, but <32A can be used by the galley and the AC panels (aircons etc) not at the same time, limited by the inverters max output (peak is up to 9000W for 3 sec).

There is a separate existing 12 DC circuit that gets charged from the charger connected to the AC panel, so this circuit is only for the inverter and the AC.

I plan to use Victron bluetooth app for monitoring. I can upgrade with a Cerbo GX etc later if I feel the need.
I don't plan to use the AC out 2 (only active when AC input is connected)

The batteries has internal BMS.

[mstr_cmdr]

Originally Posted by Nor

I've made a drawing. This is 230V.

The 32A going to the galley and 32A going to the AC panel can not be maxed out at the same time, the inverter can't deliver that much, but <32A can be used by the galley and the AC panels (aircons etc) not at the same time, limited by the inverters max output (peak is up to 9000W for 3 sec).

There is a separate existing 12 DC circuit that gets charged from the charger connected to the AC panel, so this circuit is only for the inverter and the AC.

I plan to use Victron bluetooth app for monitoring. I can upgrade with a Cerbo GX etc later if I feel the need.
I don't plan to use the AC out 2 (only active when AC input is connected)

The batteries has internal BMS.

Your schematic shows that the battery output cables to the inverter/charger are only 35mm^. I think you will find that is seriously under-sized. I would recommend, at a minimum, double 70mm^ cables. I have attached the Victron schematic for reference, which recommends a minimum of 70mm^ cables from bus to inverter/charger input.

[Nor]

Originally Posted by mstr_cmdr

Your schematic shows that the battery output cables to the inverter/charger are only 35mm^. I think you will find that is seriously under-sized. I would recommend, at a minimum, double 70mm^ cables. I have attached the Victron schematic for reference, which recommends a minimum of 70mm^ cables from bus to inverter/charger input.

This is a 48V battery bank, and in the Multi RS manual they write 35mm2 for up to 2M cables.

Minimum cross section (mm2) per + and - connection terminal
0 - 2 m 35 mm 2
2 -5 m 70 mm 2

edit: they write: "When used in closed conduits cable size should double."
What does this mean?

[sailingharry]

Originally Posted by Nor

I'll connect the inverter to the AC panel input where the generator is currently connected. The generator will also connect only directly to the inverter.
I will (obviously) not run the generator when the shore power is connected. Still do I need a switch between the generator and the shore power, so that the generator doesn't see any power on it's output (when it's not running)?

I just re-read your original post, and saw this part. You had responses about the inadvisability of it, etc. But I don't think the question was directly answered.


I'm pretty sure that an AC generator is nothing but a coil spinning in a magnetic field. If you connect shore power to the output of the generator, you will have nearly a dead short (just some resistance, and because it is A/C, some inductance -- but basically just a few ohms). If you connect shore power to the output of the generator, at best you will trip the breaker, at worst fry your generator. Forget any safety issues, or best practices, or ABYC compliance, or anything like that. It just won't work!

[s/v Jedi]

Originally Posted by sailingharry

I just re-read your original post, and saw this part. You had responses about the inadvisability of it, etc. But I don't think the question was directly answered.


I'm pretty sure that an AC generator is nothing but a coil spinning in a magnetic field. If you connect shore power to the output of the generator, you will have nearly a dead short (just some resistance, and because it is A/C, some inductance -- but basically just a few ohms). If you connect shore power to the output of the generator, at best you will trip the breaker, at worst fry your generator. Forget any safety issues, or best practices, or ABYC compliance, or anything like that. It just won't work!

This is one of the dangers I warned about and why I like to see the rotary selector switch. I once had shore power feed back into my genset and it killed the residual field, so it wouldn’t work anymore until I re-flashed the field. Not funny!