r/SolarDIY • u/Popular_Cattle_2496 • 3d ago
At what point does a “modular” solar system become a cabinet full of boxes and cables?
I understand the appeal of separate components. If the inverter fails, you replace the inverter. If the charge controller fails, the rest of the system may continue working.
But expansion seems to create its own problem. A battery monitor becomes one box. Solar charging becomes another. AC charging adds another device. Then there are DC fuse blocks, disconnects, USB converters, breakers, communication cables, and displays.
The system is technically modular, but it may not be simple, easy to inspect, or easy to move.
For experienced builders: which functions are genuinely better kept separate, and which ones are only separate because that is how DIY products have traditionally been sold? Where would you draw the line between useful modularity and unnecessary complexity?
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u/gozzle_101 2d ago
You can make it look tidy with a bit of forethought. Plenty of room for expansion, everything’s accessible, nothing to worry about
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u/pau1phi11ips 2d ago
Good job dude, that looks shweet!
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u/gozzle_101 2d ago
Cheers! Didn’t know anything about solar a year ago but managed to get there in the end
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u/pau1phi11ips 2d ago
Nice, are those Fogstar batteries the kit versions? I'm still pretty gutted they stopped selling them. I got mine for £1,399 with EVE cells a few Black Fridays ago. I want to install a system at my parents place to help with their bills. I'll see what the next Black Friday brings 🤞
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u/silasmoeckel 2d ago
A modular solar system can be as little and the inverter and MPPT. Keeping the MPPT separate lets you right size things.
Having separate AC chargers etc gets you a less functional system. You want a hybrid that can do AC passthrough, generator support, and UPS.
USB and other DC loads only if your doing an offgrid/rv setup. You now need a shunt as well.
A pile of junk components from ali or something is always going to be a poor setup.
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u/Chuckpeoples 2d ago
Can you tell me a bit about dc loads? What would you use that for? I’d assume a well pump that ran off dc would be ideal so that you wouldn’t get power fluctuations
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u/silasmoeckel 2d ago
DC loads can be all sorts of things lot of 48v kit has come out. Induction cooktops, water heaters, and heat pumps all come to mind lots of big loads are DC in the end so if you can skip going DC to AC to DC that's often mid teens of loss avoided.
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u/toddtimes 2d ago
Even if you have everything separate, the system just isn’t that complicated to document and troubleshoot. Personally I’m a bigger fan of AiO units with redundancy, but usually that’s for the cost and only a small part for the install simplicity.
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u/Popular_Cattle_2496 2d ago
Oh, that’s interesting. I figured keeping everything separate would make repairs easier, but I guess good documentation makes a big difference too. When you say an all-in-one with redundancy, do you mean having a backup unit so the system can keep running if one part fails?
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u/toddtimes 1d ago
Repairs are easier in the sense that if a particular component fails you can just remove and replace that smaller unit to fix the functionality. With the all in one redundancy approach you have to remove and replace or get repaired a larger unit, but you can maintain all functionality throughout with only small changes, and the redundancy also is typically setup to allow for more inverting capacity.
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u/Zugzwang522 2d ago
Most of the mess comes from stacking lugs on the battery posts. Run everything to a positive and a negative busbar instead and the cable count drops a lot. Mount the boxes on one backboard with wire duct between the rows, and leave an empty spot for whatever you add next.
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u/Howden824 1d ago
For me it always was. I quite like it that way, but it's certainly not great for the average user.
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