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chassis grounding clarification


Yesterday, I received a SmartSolar 100/50 charge controller ordered thru Amazon. It's to be installed in my RV. Going over the manual (version 02, Sept. 21st 2017), section 3.2 states 'The charger must not be connected with grounded PV arrays (one ground connection only)'. Does this mean I should not be grounding my solar panel frames to the RV chassis? My plan was to ground the solar panel frames to the RV frame in one location and ground the charge controller housing to the RV frame at another location. According to the statement in the manual, this should not be done. Please clarify the statement for me so I have a better understanding. Thank you for your time.

Kind regards,

Michael Bonnar

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ripper answered ·

They want two wires running from the solar panel to the mppt. As the frame of the panel is isolated from the wafers that are making the electricity you can ground the frames to the chassis as much as you want and bolt the mppt anywhere you want too. You also need two wires running to the battery as the unit is also isolated against the mounting holes.

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That is my understanding, the manual is not specific.

Thanks for your input. Have a wonderful day.

Okay on this note I have an additional question. My four charge controllers chassis are bonded with my inverter chassis and will be bonded to my solar panel frames and then to the chassis of the coach, but my question is this is installed in a motorhome and my battery negative buss bar is also grounded to the chassis. Both positive and negative wires for each array go through DC breakers. Am I missing anything?

You are good as long as neither the positive or negative leads to the INPUT of the MPPTs are not grounded

The mppts are landed on the buss bars which ultimately go to a chassis ground vis the buss bars. Is this right?

Yes you should be connecting the system DC negative bus to chassis ground somewhere (just one place).

The Victron manual states that the MPPT chassis is NOT connected to battery negative, so if you want the chassis grounded, you'll need to do it yourself. But from the wording it sounds like it is not required.

Yes I daisy chained the MPPTS chassis’s’ together and plan on taking the to the same motorhome chassis ground point my inverter chassis are grounded to and ultimately the PV frames. Will this cause an issue with my mppts since the negative buss bar and frames and device chassis all land on the motorhome chassis. Or should I forgo any of the above being chassis grounded to the motorhome

No, since the MPPT chassis are not connected to the battery negative.

They will be via the motorhome chassis connection since the buss bar I also ground to the motorhome chassis. I guess that’s why I’m confused.