Xpm-78 -All the amenities/No generator

[Whodgins]

Hi Wayne,


If I'm following you correctly, I don't think the Multiplus devices operate the way you want them to. Or maybe I don't understand them either...


But my understanding is that they are always either inverting OR charging, but never both. They can be set up to only charge, but in that case they will not invert.


I think you want them to invert at 60hz on the output side, while simultaneously accepting 50hz on the input side and using that to charge. But I believe they can only do one of those things at a time.

Thanks so much for getting back so fast Peter and with your typically insightful questions and comments. I've parked myself in front of the computer here today and am doing my best to not get called away to the shop floor too much so I can get a bit more caught up. Much as I am loving the whole build process, it is a real treat to be able to do get away from it a bit and get caught up with you and others here.

Re the inverter/charger situation, my understanding is the same as yours, they can only be in one mode at a time, not doing both charging and inverting. That is workable in our case because the only time we would be using the charger side of the MultiPlus units is when we are on shore power which in our case is very infrequent. And when we are on shore power, we are most often leaving the boat somewhere for awhile to go get some Gramma and Grampa time and see some shore side friends and family so we don't need the inverter function when not aboard the boat.

In our setup and use case, when we are aboard we are charging the batteries either by solar/MPPT at anchor or by the alternators when underway and neither of these affect the MultiPlus units. Therefore we mostly only use the MultiPlus as inverters and as per another question earlier, we might be better off separating charging from inverting but there are so many shared parts within each of these individual chargers and inverters, and given how infrequently we will use the charger function, that going with combination inverter/chargers was the better choice for us. Also less units, less external complexity and perhaps less maintenance over time.

Make sense?

 

[Whodgins]

Pretty much correct.
When supplied with AC; the Multiplus will switch through the supply AC to the output side, and also use the AC to run the charger; charging the batteries.
The Multiplus can also 'boost' the output by using the inverter to assist, giving higher peak-load handling when on limited-current shore power, but generally, on a Multiplus, if there's AC present at the input, that AC is passed through to the output.
The neutral-earth bond is also opened at the Multiplus; relying on the supply source's neutral-earth bond.
When operating purely as an inverter (no AC input present); the neutral-earth is bonded at the Multiplus output.

Thanks. As per my note just now to Peter, your description of how the AC works going in/out of the MultiPlus units and how the division between charging and inverting works, matches my understanding.

As you noted, the MultiPlus also does a good job, IMHO, of handing the super important grounding side of things with the AC which was an important factor in my choices too.

Because we so rarely have any shore power input, I've designed our system accordingly and so we don't do any AC pass through with the MultiPlus and really only use them as inverters most of the time as there usually is no AC input and no AC pass through in our case.

 

[Whodgins]

Been following that amazing build...

Thanks for joining us! Hope it continues to be good entertainment and perhaps a bit of learning.

-Wayne

 

[sunchaser]

Wayne
There will be some fairly high thermal loads from the inverters during anchoring. Has Victron provided sufficient details as to ventilation requirements and reduced inverter output at higher temperatures?

 

[Fletcher500]

Wayne, that looks like an amazing vessel you are building. I look forward to following along here, and on your Blog.

 

[twistedtree]

OK, so here’s how I think it will work of various flavors of shore power. Is this right?

On 50hz shore power the 230V inverter set will pass through shore power and charge batteries. And the 120V set will reject shore power and remain in invert mode.

Then on 60hz power the 120V set will pass through shore power and charge batteries, while the 230V set will reject shore power and just invert.

 

[Whodgins]

Wayne
There will be some fairly high thermal loads from the inverters during anchoring. Has Victron provided sufficient details as to ventilation requirements and reduced inverter output at higher temperatures?

Good point and we do have both passive and active ventilation for the whole basement area but I don't currently have any data from Victron on any estimates that they might have on ventilation requirements. I'm aware from the units on my previous boat that they do produce a fair bit of heat but I was able to passively vent those and didn't seem to loose too much performance wise. However I am aware of the surprising amount of drop off from these units as the temps go up so definately work working on.

Fortunately it is relatively easy for us to add more venting to these units if need be so we'll go with what we have designed so far and then monitor them in the real world and see if adding more ventilation and cooling would be needed or advantageous.

Thanks,
Wayne

 

[Whodgins]

Wayne, that looks like an amazing vessel you are building. I look forward to following along here, and on your Blog.

Thanks Fletcher, we are super pleased with the way it is all turning out and can't wait to be back to living onboard and at sea.

Glad to have you along for the ride and appreciate your time and input along the way.

- Wayne

 

[Whodgins]

OK, so here’s how I think it will work of various flavors of shore power. Is this right?

On 50hz shore power the 230V inverter set will pass through shore power and charge batteries. And the 120V set will reject shore power and remain in invert mode.

Then on 60hz power the 120V set will pass through shore power and charge batteries, while the 230V set will reject shore power and just invert.

Correct. I think this setup gives us the flexibility to cover number of different scenarios in terms of what the shore power available is and what we need onboard the boat. Our two scenarios when we’re pluged into shore power are A. we are living onboard and have the usual AC/DC requirements or B. We are leaving the boat and basically just want to use this as a backup in the event that all the solar stops working. When we are not living aboard the boat's power needs are very minimal so no shore power connection is really needed at all. We could leave as many solar panels "on" as we thought the solar conditions there needed to just keep the batteries topped up which in turn can power whatever minimal systems we wanted to keep going or available while we are away and any AC is all inverted as usual.

However, it would be smart to allow for a backup option if there were to be a complete shut down of all the solar charging, and in this case we then having a shore power connection available would work be smart and it would be set up as you outlined such that we cover both having the boat’s batteries stay topped up and any AC requirements onboard are handled.

Where we have 230V shore power I suspect we will most likely just turn the 120V Multi’s off completely as we do not currently expect to have any 120V requirements that would be needed when we are not aboard.

With 220V shore power there is also a third configuration option should we ever want it and that is to use the Isolation Transformer to convert the 230V input to 120V output and feed this to the 120V Multi which would pass through the 120V and charge the batteries. The 220V Multi would have no AC input and would be used to invert only and provide for any onboard 220V requirements. Not sure this would ever be needed but it is an option I think?

Appreciate you going through this all with me, thanks.
-Wayne

 

[FF]

"We have gone to great lengths to over insulate all the living spaces and so that should increase our efficiency dramatically when it comes to AirCon"

In our tropical cruising , with a far smaller boat , we use deck sun shades with deep side panels to keep the daily hull heat load down.

WE use a late PM seawater cooling wash down , and by venting the uninsulated bilge up, the boat would quickly become sea water temperature.

Also in colder limes we would circulate the 6-71 coolant into the cabin with a box heater. Enough to knock the chill off in fall evenings .

OF course in real cold the Dickinson oil furnace would be on for 5-6 months .

Battery or eutetic reefer energy storage was a simple choice for us. With eutetic the house batts can be small ,so small charge times , and small replacement costs were key.

Boat size does matter with systems choices.