Is my starter battery negative also a ground point?

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Neo Nos asked Jan 29, '24

Is my starter battery negative also a ground point?

Sorry not sure this is the best place for this question but I'm aetting up my all victron house battery system and I noticed all tutorials always look gor the so hard to reach at times manufactur provided ground and share a common ground with the vehicle...

Wouldn't it just be easier to use the starter batterys negative terminal as my ground? As it is already connected to the vehicle Chasis. (I presume so in my Ford Transit Van)

And if ssois there any technical difference? Is it a problem for ground to travel through the car syste?

Any help would be appreciated.

Grounding campervan starter battery

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Answer 1 · 2024-02-02T07:35:21Z

Paul B answered · Feb 02 at 07:35 AM

On a vehicle yes you can use the negative as the ground. As it's attached to the cars body.

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celts88 commented · Feb 04 at 02:05 PM

Sorry if dumb question but how can a caravan be grounded when the vehicle is disconnected from the vehicle?

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regman54 celts88 commented · Feb 04 at 03:36 PM

@Celts88 The current needs a loop. In a vehicle it's a chassis ground, not an earth ground. Similar to putting an AA battery in a flashlight the current needs to flow back to the battery through the case to make the lightbulb glow.

I'm sure there are others here much more educated than I to provide a more complete answer but that's the basics.

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kevgermany ♦♦ celts88 commented · Feb 04 at 05:26 PM

If you have shore power, then ground is through that connection. If not, neutral and ground are connected. With Victron inverter chargers, this is automatic. Ideally with a caravan, you drive a metal pole into the ground and connect the chassis to that. Few people bother.

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regman54 celts88 commented · Feb 04 at 07:07 PM

Kev's comment about shore power reminded me that some RVs may have an EMS (Electrical Management System) installed and if a ground rod is used it will likely interfere with the EMS's operation if not turned off. If it's not turned off you'll definitely hear it complain.

If you are not familiar with EMS devices they are usually an aftermarket device installed to protect the RV from possible faulty AC campground pedestals (or other wall outlets with faults) so something to be aware of. I know they don't play nicely with AC inverter generators with floating grounds and ground rods. I won't get into the details here but you can do a search online for more information about their use and if it applies to you or not.

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