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farmer-giles asked

SmartSolar MPPT chassis grounding confusion for camping trailer

I'm building a small camping trailer with built in kitchen and roof tent. I'm starting with just PV to begin with, I may add mains hook-up and an inverter later. I don't intend to add split charging. The plan is to use a Victron 140W PV panel to charge a 110Ah leisure battery through a SmartSolar MPPT 100/20 controller ( I may add another panel later). I've added a picture of the first stage. My question is about grounding on the output of the controller. I get the PV side, no issue. On the load side of controller, does the negative also go to chassis ground?

camping-trailer-wiring.jpg

Thanks

Andy

Grounding
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farmer-giles avatar image farmer-giles commented ·

I noticed I made a couple of errors on the diagram, most embarrassingly I had the load polarity the wrong way round. I also had the wrong fuse size on the battery side of the controller, I've amended both these errors.

I have read the manual again, plus the wiring unlimited section 7.7 on system grounding. Unfortunately the examples assume the DC component is just to feed the battery and an inverter for an AC load, there is no example with a DC user load. I intend to use the charger for 12v DC appliances only in stage 1. here's and updated diagram with the relevant manual and wiring unlimited sections.

camping-trailer-wiring.jpg


So I am still none the wiser on the DC load side in terms of whether to ground the negative rail or not. The manual examples also assume the use is in a static building, it would be useful to have a section for vehicle use in terms of grounding.

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farmer-giles answered ·

Looks like I'm answering my own question :) I've found this resource on grounding, there are 4 PDFs that cover all use cases.

AC & Household

Stationary systems

Solar Panels

Mobile systems (the one I wanted advice on)

Best explanation I have found given Victron's documentation doesn't cover everything clearly, at least in my opinion.

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nonemauro answered ·

Thanks for sharing the resource. I am also perplexed on if I can connect my Victron 100/50 the to same negative bus bar as the main ground which is connected to the vehicle chassis.

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kevgermany avatar image kevgermany ♦♦ commented ·

Output side yes. But do it at the battery.

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