I’m planning to add extra deep cycle battery to my RV.

It will be charged by the alternator safely by an isolator. I’ll use national parks’s power outlets to charge it.

My main concern is the grounding points.

As the alternator that’s charging the main battery is grounded to the engine.

My auxiliary battery is grounded to the chassis. Same applies to the isolator & the load.

Should I connect the chassis ground point by ground cable to the engine bay grounding point to make it safer? The load will be 50 amps.

Or this setup I attached will be sufficient? Please tell me if what am doing is correct or not. enter image description here

  • I’m thinking of adding a switch prior to the load too to avoid any current drainage when the rv is sitting idle.
    – Wild Star
    Jun 1, 2019 at 22:34
  • I wouldn't think you'd need to, as long as you have a good, clean grounding point on the chassis, it should be fine. Just a thought, though. Jun 1, 2019 at 23:02

1 Answer 1


For your two questions:

  1. Grounding to the chassis is fine - remove paint so it is clean and tight,

  2. Putting a switch (battery isolators are available - perfect for this, ie sufficient current capacity) is a good idea.

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