Bought one of those ubiquitous voltmeter and USB combos from bangood.com. Thought I would modify the vent on the fridge cabinet to install. But the old grill on the rear face of the cabinet had peeling paint and I didn’t like how the install looked. So I made a new grill from some 3/32″ thick aluminum plate. I milled slots, 3/8″ wide, on 1/2″ centres, 7 slots in total. And I milled a hole for the voltmeter/outlet combo.
The grill turned out a bit “gappy”, a bit too open perhaps. But as you don’t really look at it face on too often it’s good enough. The outlet and meter are wired to my auxiliary fuse panel under the driver’s seat. I thought about a switch to turn the thing off when not needed but I didn’t have a switch that would suit. I might add one later, but right now my big assed house battery will take any parasitic drain.
I’ll replace the mounting screws with the ones that will accept a plastic cap when I can find some.