Camper control panel and switching system: add, replace or combine

The control panel is the nerve centre of your motorhome. This is where you switch the lights and the water pump and read the battery voltage and tank levels. In most vehicles, though, it isn't the only one: heater, boiler, solar charge controller, battery computer, air conditioning and fridge each come with their own control unit. This article explains how a camper control panel and switching system are put together, which types there are and how you add to an existing panel, replace it or bring all the controls together in one place.

How a motorhome switching system is built

Almost every motorhome has two parts that work together:

• Power distribution unit (in Germany called EBL) or distribution box: It usually sits under a seat or in the wardrobe. This is where the leisure battery, starter battery and shore power come together, and where you find the charger, the isolation relay and the fuses for the individual circuits.
• Control panel: the visible part on the wall, often above the entrance door. It operates the main switch, lights and pump and shows voltage and levels. Some people call it an info system, control centre or operating panel.

The panel and the power distribution unit are connected by a data cable and usually come from the same manufacturer. That's why you can rarely just swap a panel for one from another manufacturer.

Which types of RV control panel are there?

Type	Typical for	What it can do	Limits
Simple panel with LEDs	Older vehicles, caravans	Main switch, pump, lights, tank level in a few steps	No exact values, no history
Digital panel with display	Newer motorhomes	Voltage, current, levels, often with a menu	Usually only shows devices from the same manufacturer
Factory-fitted touch info system	Premium semi-integrated and fully integrated motorhomes	Many devices on one screen, some with an app	Tied to the vehicle model, hard to expand
Retrofit central unit	Existing vehicles, self-builds	Devices from different brands in one place, automations	Only devices whose interface has been integrated

Why so many control units?

Every device manufacturer supplies its own control unit. A well-equipped panel van quickly ends up with five to seven of them: power distribution panel, heater, boiler, battery computer, solar charge controller, fridge, air conditioning. Each one works differently, each has its own symbols and menus. The result: you look for values in several places, and the devices can't respond to each other. The heater knows nothing about the battery level, the boiler nothing about surplus solar.

The interfaces: CI-Bus, CAN, LIN and more

For a central unit to control a device, it has to speak its language. The most important interfaces in a motorhome:

• CI-Bus: a standard agreed under the umbrella of the manufacturers' association CIVD that lets devices from different manufacturers talk to each other. Technically it is based on LIN. But not every CI-Bus device understands every other one.
• CAN: the robust bus system from cars. Many batteries, chargers and newer heaters offer it.
• Manufacturer-specific interfaces: for example VE.Direct from Victron or the W-Bus on older Webasto heaters. Victron's VE.Can is technically a CAN bus with its own protocol.
• Remote switch input: a simple on/off contact, on an inverter for example.

Camper Jarvis connects a device via CAN if it offers it, otherwise via CI-Bus or the manufacturer's own interface. The modules come with the right cable for your device.

Three ways: add, replace or combine

1. Add: the panel stays, a smart layer is added

The most common and simplest way. The power distribution unit and the panel stay as they are. The central unit takes the values directly from the devices and shows them together. From then on you control everything in one place, and the old panel stays as a fallback. Good for vehicles whose electrics work and just need to be easier to keep track of.

2. Replace: the power distribution is redone

For a self-build or when the electrics are being renewed, you can replace the fuse box, relays and switches with electronic power distribution. With Ampy every load gets its own output with an adjustable fuse, current measurement and a wall push button input. How this is set up is explained in Camper power distribution.

3. Combine: the many device panels move to one place

Heater, air conditioning, fridge and power system are connected through their interface. Instead of using the small original control unit, you set temperature, timer and operating mode on the SmartKnob or in the dashboard.

The diesel heater in the dashboard: target temperature, heating or ventilation and timer in one place.

The heater right on the SmartKnob: turn for the temperature, press to switch off.

• Heating: Heaty. Which heaters are already supported is listed in the heating compatibility list.
• Air conditioning and fridge: Thermy. You will find suitable devices in the air conditioning and fridge compatibility list.
• Battery, solar, charger, inverter: Volty Pro. You will find suitable devices in the power compatibility list.
• Tanks, temperatures, water pressure, leaks: Fluidy Pro.

Important: Some manufacturers require their original control unit to stay installed. With Truma, for example, the control panel always stays in the vehicle, even if you operate the heater from somewhere else. Place the original unit so you can reach it without tools if something goes wrong.

Campervan digital control panel: rotary knob or touchscreen?

Many info systems rely on touchscreens. In a vehicle they have drawbacks: they respond poorly to wet fingers or gloves, in the dark you have to look at them, and a tap in the wrong place switches the wrong device. A rotary knob with noticeable detents can be used without looking. Turn to select, press to confirm. That's why the SmartKnob is a rotary knob with a display, with the dashboard on your phone, tablet or laptop as a second way to control things.

Checklist before you retrofit

• Have you noted all devices with manufacturer, model and year?
• Do you know the interfaces: CI-Bus, CAN, VE.Direct, W-Bus or just a remote switch input?
• Is your electrical system 12V or 24V? Camper Jarvis works with 9 to 36V.
• Where will the central unit go? Ideally where you pass by every day.
• Which wall push buttons should stay? Wired buttons connect to Ampy or Lighty.
• Are there 230V appliances you want to switch? Then you need Switchy and a qualified electrician.
• Does an original control unit have to stay installed?

There's more about the whole system in the guide Camper van smart home.