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Two separate solar charger/inverter systems will be installed on a camper, each with a separate ground connected at two separate points on the chassis. Is this logical? The likelihood of them discharging at exactly the same time seems unlikely, and even if they did, there is probably enough material to handle it. I just want to hear perspectives on if this is reasonable.

I fear my question is kind of basic compared to many of these posts, but I am having trouble finding an answer that makes sense. Also, I promise to hire a certified professional to double check my plans but just want to make sure there isn't a glaring hole in my logic while thinking about the set up.

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  • \$\begingroup\$ Hi. To me, it is not quite clear how you want to connect the modules to your chassis, to each other, to your appliances etc. Could you make a quick and dirty block diagram? \$\endgroup\$
    – tobalt
    Commented Nov 16, 2022 at 18:19
  • \$\begingroup\$ They wouldn't be connected to each other at all, and would connect at the chassis in two different spots. I am following the plans at explorist.life/… for my camper but will have two of these systems (there is a nice diagram on the page). Hopefully this helps but let me know \$\endgroup\$
    – Elise Vinson
    Commented Nov 16, 2022 at 19:10
  • \$\begingroup\$ From the standpoint of fire and shock hazard, the presence of these two ground connections on a single vehicle chassis is not a big concern. I'd be more concerned with how you distribute the 120V output of the inverters. I've submitted an edit to your question to clarify the nature of the "ground" wires and that this is a vehicle solar inverter/charger system. \$\endgroup\$
    – Theodore
    Commented Nov 16, 2022 at 20:06
  • \$\begingroup\$ IF the two systems can have their batteries charged by the same alternator (as implied by looking at the link - may not apply here) then they are NOT fully seperate systems. If the chassis is used for alternator to 2 x [solar system including battery] then you should ensure that chassis resistance between the two is minimised. If good reliable contact is made to the chassis with adequate earth wires then it should be OK. A suller picture/description of the overall system would help. The question is potentially basic but also has potential for complexities. More detail will help. \$\endgroup\$
    – Russell McMahon ♦
    Commented Jan 1, 2023 at 11:13

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Assuming you are concerned about the grounding, then, as long as the electrical resistance is low between the two separate grounding points on the chassis, you should be fine.

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  • \$\begingroup\$ How does the resistance between the points matter? The two systems are meant to be independent. \$\endgroup\$
    – Theodore
    Commented Nov 16, 2022 at 20:11
  • \$\begingroup\$ Current maybe drawn from between these two points. If resistance wasn’t a consideration, then they wouldn’t need to be joined to begin with. Nevertheless, voltage sources need to be fused based on the current capacity of the wire (ampacity) and extra attention to the routing and physical protection of the wires as vibration on mobile installations can cause problems. \$\endgroup\$
    – Kartman
    Commented Nov 16, 2022 at 22:02
  • \$\begingroup\$ @Kartman The resistance of the chassis matters where it's used for return currents, but that would be the case with even a single source. The diagram shows DC loads all landing at a terminal block with both positive and negative terminals, not returning currents through the chassis. \$\endgroup\$
    – Theodore
    Commented Nov 16, 2022 at 22:35
  • \$\begingroup\$ How about fault currents? \$\endgroup\$
    – Kartman
    Commented Nov 16, 2022 at 22:39
  • \$\begingroup\$ Seconding Kartman's comment. In the case of a fault, you'd want the fault current to flow through the chassis. A significant resistance on the chassis could cause the fault current to build enough voltage on parts of the chassis to electrocute someone (God forbid). It could be an exaggerated concern but it's better to crunch the numbers to be safe. \$\endgroup\$
    – MAI85
    Commented Nov 17, 2022 at 21:16

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