durval avatar image
durval asked

Phoenix Smart inverter grounded to my RV chassis, should the negative of the (dedicated) battery feeding the inverter also be connected to the chassis?

As per the title above. I searched through the excellent Victron Wiring Unlimited guide and here in this forum, but couldn't find an answer.

Just to make it clearer, I say it's a ''dedicated" battery because it's completely separated from the vehicle's pre-existing battery system, and it's connected only to the Victron inverter (with separate 70mm2 cables) and to my PV charge controller.

Thanks in advance for your help.

Phoenix InverterwiringGrounding
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1 Answer
klim8skeptic avatar image
klim8skeptic answered ·

What is the point if your inverter and inverter battery is separate from the RV electrical system?

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durval avatar image durval commented ·
The point in keeping the two separate is to avoid messing with what's working :-) that is, the vehicle's original 12V system is kept untouched and will continue to work as-is, exactly as the day it left its factory.

The PV Charge Controller plus the inverter plus the separate battery bank they are connected to, constitute a separate system dedicated to 220VAC.

Now that (I hope) this is clarified, can we please get back to my original question? ;-)

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wkirby avatar image wkirby ♦♦ durval commented ·
I think klim8skeptic's question was more rhetorical.

It seems that the two of you agree that there is no real reason to connect the inverter battery negative to chassis in favour of keeping the two systems separate.

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durval avatar image durval wkirby ♦♦ commented ·
Can't speak for @klim8skeptic but I myself have not agreed to anything :-) seriously, and trying again to be more clear:

1) on the system I've described above, both the inverter and the PV Charge Controller are grounded, using their specific ground terminals, to the vehicle's chassis. This was done in accordance with their installation manuals and is not in doubt.

2) my only doubt is whether I should *also* connect, to the same chassis grounding point, the negative pole of the battery bank (this of course in addition to the normal 70mm2 battery cables that's already connecting the battery poles to the PV Charge controller and the inverter).

So, can you (or anyone) help me answer #2 above?

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wkirby avatar image wkirby ♦♦ durval commented ·
If you want to keep the systems separate then don't bond the battery negative to the chassis.

If the systems need to share the chassis negative then you should bond the house battery negative to the chassis.
Examples of this may be:
Alternator charging from the vehicle with a common negative B2B charger?
Are there any circuits which are fed from the house battery whose negatives are also referenced to the chassis negative?

You would know the answers to those sort of questions, so that is why previous answers are open ended.

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Related Resources

Phoenix Inverter product page

Phoenix Inverter Smart product page

Victron Wiring Unlimited Book

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