I built my three panel BATTERY MONITOR from a PVC 3-GANG Swicth electrical box and specialty wide switch panel. This is mounted vertical on my cabinet panel I can open the front door and see from the outside when checking things.
The small digital readouts were glued to the back of the specialty switch panel
Routed all of my battery wiring back to the battery switch area using PVC FLEX Conduit and weathertight boxes for terminal connections etc... Each DC line is fused to protect against DC shorts.
Finished three meter panel
Mounted in cabinet with good view. Also installed ON-OFF switch behind the panel as the LED READOUTS turned out to be pretty bright.
Wiring schematic for my BATTERY MONITOR PANEL
Meters from SURE ELECTRONICS ebay/China
PVC items from LOWES
Roy Ken