This is the layout for the auxiliary (house) battery management panel I'm making for my boat. One for my motorhome will be similar. (Differences noted below.)
The panel itself is a 1/8" thick sheet of black UV-resistant nylon plastic.
The large circle on the top left is an ON-OFF battery switch, for disconnecting the battery when the boat isn't being used.
The large circle on the top right is the battery condition indicator (BCI) I mention in a previous post.
The smaller circle between the two larger circles is an OFF-(ON) momentary (spring-loaded) toggle switch, for activating the BCI when checking the battery's charge level.
The rounded-corner square in the bottom middle is a BatteryMINDer EZC-01 SAE connector for battery chargers/maintainers, permanently wired to the deep cycle battery.
The two small circles on either side of the charger connector are push-to-reset circuit breakers. The one on the left is a 15 amp for the battery charger (EZC-01 connector) circuit. The one on the right is for the mini-automatic charging relay (Blue Sea Systems m-ACR, p/n 7601).
The rectangles around the circuit breakers are panel adapters that make it easier to mount the circuit breakers securely.
The rest of the circles are #6-32 and #10-32 black oxide machine screws and washers, for mounting the panel and components.
Dashed lines indicate things behind the panel.
The eight machine screws around the outside bolt the panel to a corrosion-inhibited powder-coated angle iron mounting bracket. I have a strong tendency to consider maintenance when I design things. The machine screws and mounting bracket provide easier access to the wiring behind the panel. (Also, there's a one amp ATO fuse behind the panel on the BCI circuit.)
The two of the four machine screws around the BCI (on the right) don't serve any purpose other than to maintain a consistent appearance. The two on the left of the BCI are primarily for appearance but also attach short piece of aluminum angle to the back of the panel. (The aluminum angle keeps the toggle switch from rotating in its mounting hole.)
Notes:
I'm a bit of a fanatic on fuses and circuit breakers (collectively called circuit protection devices or CPDs) on permanently-installed and, especially, concealed wiring. I've been involved in three vehicle fires and one house fire, all caused by faulty wiring. So, I'm inclined to believe if a few is good, a lot is better ... within reason.
This panel will be mounted in an open skiff fishing boat so weather- and water-resistance is critical. The EZC-01 charger connector has a permanently attached cap for when the connector isn't being used. Likewise, there are boots, attached to mounting nuts, available for the toggle switch and pushbutton circuit breakers. (The exposed portion of the battery switch and BCI are rated IP67.)
Assuming a similar panel is mounted inside a motorhome coach, a different momentary switch and other type of circuit breakers would be equally suitable. Likewise, some other material, such as 1/8" thick plywood, would be suitable for the panel itself.
The size, equipment, and planned operation of the boat doesn't justify a permanently installed battery charger. The EZC=01 connector provides a clean, easy way of connecting a battery charger, without opening the battery compartment, when shore power is available. (This also eliminates unused, unnecessary weight when the boat is underway.)
On the other hand, permanently installed battery chargers are preferable in a motorhome. So, I'd eliminate the EZC-01 connector on a motorhome version. (In this case, I'd keep the battery charger circuit breaker ... just to be on the safe side.)
