I built up a three digital meter panel for my off-road POPUP battery banks. My bank includes two groups of 12VDC batteries and with the selector switches I am I using I can select either one of the battery banks providing DC power to my trailer. I am using a PD9260C 60AMP smart mode converter/charger unit to maintain these two 12VDC battery banks.
My panel includes a 12VDC digital meter for each bank and a single DC current meter that will show how much current is being drawn from the selected batteries or how much current the selected batteries is using being re-charged.
I mounted my digital meters in one of these three gang speciality switch WALL PLATE from Lowes. The larger switch openings just fit these three meters perfectly and they are glued in place using RTV sealant. I mounted this 3-gang switch into a regular three gang size PVC electrical wall box. All of the cables going to my battery switches are inside flexible PVC conduit.
The digital LED meters are DC VOLTMETERs models ME-SP038 7-30VDC and DC HALL EFFECT CURRENTMETER model ME-SP230 +/-75AMPS. These meters are available from SURE ELECTRONICS ebay/china...
I also installed a toggle switch feeding each digital meter as the brightness of the LED Meters is very bright - makes a super bright night lite in the dark. I did elect to use a SPST switch however instead of a spring loaded switch as I do like to keep the meters powered up when I am working on things.
I also mounted my meter panel near the outside entrance door so I could switch my batteries and make checks on the outside where the batteries are installed and then just lean into the trailer to observe the meter reading.
Camping off the power grid requires pretty close monitoring of the DC voltmeters as you try not to let the batteries get discharged below 12.0VDC before re-charging them otherwise it may do harm to your batteries. The DC CURENT meter is also an excellent meter to have as well. You can watch the DC current drain in real time and really get to know what draws alot of current and when it is happening. The reverse of this is when you are re-charging your batteries from the on-board smart-mode converter/charger unit you can watch the actual DC CURRENT along with the DC VOLTAGES as your converter/charger unit is going thru it smart mode charging sequences... Seeing the proper levels of DC current when charging the batteries is telling you the converter is working properly.
My meter panel does alot of good work for my situation. the only thing I don't have with the one I made up is with the more popular Trimetric model TM-2025-RV unit alot of RV'ers use has a settable audible alarm to alert you when the battery voltage is approaching 50% state of charge on the battery banks.