You might consider variations of a shelf design that fits the
components in place more securely.
Put the charger on top though so it is easy to accept a plug in
charge. The meter can also go on top, while the DC converter
to charge your 12 volt system can go on the bottom along
with the main contactor.
The batteries were configured in a 120 volt design, (20
batteries at 6 volts). The DC converter was set to this voltage
and the 12 volt car system made operational.