cw8 avatar image

Help needed vetting initial design ideas for van electrical system

Newbie here, designing a van system.

I would like help vetting the big picture design. Once the big picture is solid, I will move onto current, distances, wire size, fuses, etc. I would really appreciate your comments, criticism, and suggestions on this big picture design.

The idea is to initially start with something without a lot of solar or a large battery bank. But design/build it so that solar and batteries can be doubled. Inverter, wires, and fuses, for example, would all be sized for this later use. A few years down the road, I will know a lot more about my system and my needs.

Random factoids:
  • This is a passenger van, which will only be 'half converted', so I would like to keep the system smaller, particularly initially.
  • My 2020 Transit has a LOT of alternator power available (details in diagram).
  • Would prefer to keep my roof rack for things other than solar, for now anyway.
  • Do not want built-in propane. Will take propane/butane camp cookstove for longer trips.
  • Initially, will only use inverter cooktop/microwave occasionally - quick stop when pulling over on a road trip over, horrid weather, hot water/soup/heat up leftovers/etc. Am willing to not use when house batteries low, or when I know I will be off-grid for longer. In a few years, I will know more about whether this restriction is one I want to keep.
  • Traditionally, I don't tend to stay in one place for long, and with all that alternator power available, it is not obvious that I need a huge bank. Having said that, with all the kids we have now, this may change. Time will tell.
  • For the next few years, this van will only be for weekend camping trips, and road trips. A few years down the road, when kids older, it will be used more off-grid.
  • Would add an audible alarm, hooked up to inverter/charger, to warn when too much draw. I'm not the only one using this van, and others may not remember "the rules". Initial phase would probably have one and only one easily accessible AC outlet from (battery side of) inverter, to preclude running more than one heavy hitter at the same time.
  • All Victron, except for solar panels, and possibly batteries. I've been super impressed with the help and knowledge available in this community, and I like the fact that they play well together and have great monitoring. I'm willing to pay up front for something safe and reliable that I will not have to replace/fix later.
To keep this uncluttered, a lot of my thinking is 'encoded' in the diagram below. For example, at first I thought that with 2x 175w panels, I should be fine with an MPPT 100/30, which is supposed to be able to handle 400w. But once I started looking into online discussions about solar panels and cold morning startups, I came to understand that, as usual, it is not as simple as it seemed at first. Even with just 2x 175w panels, I might need the 100/50. I haven't bottomed out on that yet.

I would very much appreciate

  1. A review of the possible "final" system - is it well balanced? Is there anything that stands out as unwise, unnecessary, or missing?
  2. Opinions on this "initial" system approach... is this silly / crazy / wise / doable, but...? Any time caveats here? For example, you can go one or two years before buying second battery, but no longer, to avoid mixing battery ages.

Thanks much!!


MPPT ControllersPhoenix Invertersystem designsolar sizing
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2 Answers
Matthias Lange - DE avatar image
Matthias Lange - DE answered ·

Sorry but this community is not the right place to ask for system designs. You should ask a local installer for help.

Victron provides some system schematics that you can use for reverence.

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Oops, sorry. Should I delete?

I just reread the guidelines. Honestly, it is not clear to me that my question does in fact violate those guidelines. Not trying to be contradictory, just trying to understand...

"Long, multifaceted issues involving system design, multiple run on questions with very specific installation and nuanced details are not really well suited for the structure of the community."

I did not see myself as asking a detailed design question. My primary purpose is to sanity check my "initial"/"later" approach. My "later" is very similar to what drlbradley linked. But the whole idea of starting "lighter" is something I would prefer to get general multi-person advice on, not just from my local dealer (who I am working with).

Admittedly, I did _also_ ask for general commentary, which I now retract.

Given this explanation, if you still think this entire post is not appropriate, then I will delete it.


drlbradley avatar image
drlbradley answered ·

This one seems like a good fit, I'm building something similar.

Do more research on your alternator and the perils of using alternators to charge Lithium. I went for the safe option of an Orion TR Smart to control the current.

1 comment
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Thanks for that awesome diagram link! For the record, my diagram includes that 3KA (2400w) inverter you mention, and 2-3x 30A Orions.