Tnisesm 12Pcs 3 Pin Screw Terminal Block Connector 5.08mm Pitch Pluggable with 3 Pin Phoenix Plug 300V 15A for 28-12AWG Cable

Instead of 3 Wago connectors, I'd use something like this: Tnisesm 12Pcs 3 Pin Screw Terminal Block Connector 5.08mm Pitch Pluggable with 3 Pin Phoenix Plug 300V 15A for 28-12AWG Cable, Terminals & Kits - Amazon Canada On the vehicle side, connect GND/ACC/BATT. On the device side, connect corresponding GND(2)/ACC(2)/BATT(2). To make it even cleaner, add some ferrules on the device side: Ferrule Crimping - A Must-know Technique for Makers (Tutorial)