Need some simplified grounding instructions for battery bank on a hand truck. 3 100ah agm's, a Renogy 3000w PSW inverter. Batteries are mounted on plastic battery trays with lids. Should inverter be directly attached to metal cart or to pastic board attached to cart. Do I attach a grounding wire from each to the bare metal of cart? I also made the top part of cart detachable so I could put the battery pack in the bed of my truck when using the truck camper and put the inverter inside the camper. So they would be connected via anderson plugs through the sidewall of camper.