Luca Barbierato avatar image

Van Solar Electric Scheme with PV, Alternator and External 230V Plug

Dear all,

here my idea for the electrification of the Van. First of all, do you see some error in the design? If yes, please correct me if I did something wrong. I have still some doubt:

  • A 24V 300Wp PV will manage to charge a Victron GEL 12/220Ah battery completely considering a normal spring/summer/autumn/winter day?
  • Are the cables area correct considering the cables lengths?
  • Do I need to put in the schema other fuses along the cables?
  • Where do you suggest to use a manual circuit breaker?
  • Is the interconnection of the MultiPlus correct? It is ok a 125A fuse?
  • Which kind of AC Circuit Breaker do I need to consider for such MultiPlus?

MPPT ControllersMultiPlus Quattro Inverter Chargerwiringcampervan
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2 Answers
spirou avatar image
spirou answered ·

I would put a fuse/switch between the panel and regulator to simplify maintenance.

Whether the panel will produce enough in winter largely depends on where you are. Somewhat possible south of 45° latitude, unlikely above 50°.

Another improvement would be a dc-dc converter (not necessarily victron) rather than a battery combiner between both batteries. This way the BS gets the appropriate charge voltage and profile (especially if you have a smart alternator), as well as avoiding a likely issue that comes from its 12.8V disconnect limit. I don't know about victron gel batteries but they're often full closer to 13V, while your BM is probably at 12.6V.

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I would prefer a switch between the panel and the regulator. I don't think it is necessary to put a fuse. A switch surely will help to disconnect the panel in case of maintenance.

Could you please suggest a DC-DC converter? Because I think I will need it because my van is a Fiat Ducato Panorama 2014 and it is an Euro5b.

This cost less. But now I have another question..if my alternator can reach 100A which model I need with my 220Ah battery?

I have a schaudt wa121525, there's also a 45A model. The thing is, your batteries will never accept 100A charge even if the alternator could supply it. In practice it's not even close. I have 180Ah and I'll see 25A for maybe a minute then it starts going down quite fast. This is with about 3m of 10/16mm2 wire in between. On the previous van I had a cyrix with about 6m of 6mm2 wire between batteries (120Ah gel) and I can't remember more than 15A ever passing through. Lithium is a different matter, that will suck up everything the alternator can provide.

JohnC avatar image
JohnC answered ·

Hi Luca. There's a couple of things that stand out. A missing battery isolator. And 16mm2 cables won't fit into a 100/20 (the max of 6mm2 would be adequate over that 0.25m). But there's more..

You've done a good job mapping it all out, but it might actually be easier to start with the full monty and cut out the pieces you don't need. See here, and follow the links for schematics, etc.

Then of course, the diy'ers best friend:

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As for battery isolator, do you mean a switch between battery V+ and SmartSolar Battery V+?

So you recommend to put cables of 6mm2 for the connections:

  • BM V+ to Cytrix-CT 87
  • Cytrix-CT 30 to BS V+
  • BM V- to BS V-
  • BS V+/V- to SmartSolar Battery V+/V-
  • SmartSolar Load V+/V- to DC Load V+/V- (from here a bar with all utilities protected by a switch and a fuse)
  • Multiplus Ground to BS V-

Moreover, you recommend reducing size of cables to 16mm2 from the battery V+/V- to the Multiplus V+/V-? Also in this case you recommend a switch, I imagine.

Thanks for the documentation. I will read the document on DIY. Sincerely the full monty seems to me too complicated. Probably he needs all this complex installation because of the LiFePo4 battery. In my case, I think it is better to simplify it, like in the scheme.

I was speaking generally. The two things I mentioned, the batt isolator was to isolate from *everything*, and the 6mm2 wire for one specific wire run. Just as examples..

I'm afraid we here can't design your system down to the finest detail. That's why I posted links so you could learn to diy it properly.

If you set up your system as Victron would do it, then when all down on paper it too may seem 'complicated', but you need to decide yourself what kit you need and how far you want to 'uncomplicate' it.

And no, I surely didn't mention cable sizes into a Multiplus. The recommended sizes will be in the relevant Victron manual, and you need to look that up yourself.

Sorry if this sounds harsh, but most of this minor stuff you'll need to determine yourself, to suit the particular installation.

Dear Jhon,

I will take a look at the document and I will let you know if my questions about ground are answered or not. Sincerely, when I teach my students I never refuse to give them an explanation if they are curious and picky enough to bring me an interesting problem. If you are considering that this is a question and answer community if you don't want to answer my questions please feel free to don't answer. If not, take care of my design specification and try to solve my doubts. As far as I know, this is how every community works (such as StackOverflow, GitHub and more on).

With extremely kind regards,


Hi Luca. My apologies for offending in any way. What you must understand though is this isn't a general design forum, and I think that's stated clearly in the Guidelines.

But I totally agree with you about 'interesting problems' being brought to you by your students. That's what we do here, but not whole subjects..

Many of us are volunteers and try to help out with the simpler stuff to ease the load on the Victron Staffers, who are best left to answer the more technical issues.

Your question I saw as just covering just too much territory at once. Questions on individual things are no issue, and we'll always try to help with those.

There's an old saying, "Give a man a fish and you feed him for a day. Teach a man to fish, and you feed him for a lifetime."

Tis why I initially offered up links for you to learn yourself how to diy it. Up to you how much you want to learn, but that's what I recommend.

Again, my apologies for any offence you've taken.

Please, John. Probably other people will take into account that this is an interesting problem after I will share my acquired knowledge through this community. Both your and spirou responses helped me to achieve a more reliable and secure system (let's say my main challenge!). I understand your super-user position, but there's a world of people that never get in touch with this design that needs help and assistance as me. It's a year that I read everywhere about electrification of a van. And the whole internet is full of shit. Fortunately, I'm an expert in electronic and telecommunication and I have the basic knowledge to deal with such problems. What I was asking you is a confirmation of what you suggest to me. Nothing more, nothing less. I think we can close the discussion since we have a different opinion about how to use such communities.

All good Luca. Our opinions don't really differ, but maybe you should have stated you had some experience..

Your 'final' design looks ok, but I'd maybe increase the fuse sizes a little on the batt & load side of the mppt to give a little leeway. Fuses are to protect the wires, but I haven't bothered checking them all for size.

We'd love to hear how your system performs, but you've nothing owing to repay in contributions. I just happen to be addicted to helping offgridders, tis my hobby. Silly hobby, just like a drug addiction, hey..

And all users of the Blue are my blood-brothers. You too..