Let’s look at the camper wiring steps to undertake before heading out to enjoy a few days outdoors.
A camper is a vehicle converted to allow driving and living in the same unit. The driving part is normal, but living in a car entails activities like cooking and sleeping.
So you need to wire the motor home to power the devices you need for living. Read on to learn more!
Table of Contents
Camper Wiring Steps
Vehicles typically run on 12V batteries, so we’ll focus on building a camper wiring system to run at this voltage.
A camper van at sunset
Although the wiring contains several components, the system’s core is the 12V power source. And we can’t use the car battery that powers the engine. It will drain. So let’s begin by setting up the battery system.
12V Battery System
Selecting the correct battery is challenging if you are new to the terms and chemistries surrounding this hardware. Here’s what you need to know when choosing one.
Select the Battery
The four factors to consider are the battery type, voltage, battery chemistry, and capacity (amp-hours).
- Type: Don’t buy the regular starter battery. Go for the deep cycle type.
- Voltage: Buy a 12V or 12.8V battery. You can try 24V and 48V batteries, but we recommend 12V, especially if it is your first time wiring a camper.
- Battery chemistry: We recommend buying lithium batteries over their AGM counterparts. They might be costlier but are better in many performance aspects.
- Capacity: Pick batteries in the range of 100Ah to 200Ah
A deep-cycle battery
If you are on a budget, a 12V 100Ah deep-cycle battery is a reasonable option.
Wiring Multiple Batteries Together
The good thing with batteries is you can link several of them to form a more powerful power source. So you can start with a budget battery, which offers limited power, then connect new pieces later to expand the pack.
But to keep the voltage constant at 12V, always link the batteries in parallel. This connection only increases the capacity, giving you more electrical current to power your devices.
So if you connect three 100Ah batteries in parallel, the pack’s current capacity will be 300Ah.
A bank of battery cells
Usually, one battery is insufficient. So you’ll have to connect several to run your motor home.
For this battery wiring process, you’ll need the following components.
- Red and black wires (2.0 American Wire Gauge wire rated for over 300A)
- Lugs for the 2.0 cable gauge (5/16 inches)
- Heat shrink tubing
- Heavy-duty wire cutter
- Wire stripper or box cutter
- Crimping tool (preferably hydraulic) for lug crimping
Wiring Steps
- Cut the wires to the required length
- Strip about one inch of the insulation from both ends
- Insert the wire in the heat shrink tubing, followed by the lug
- Crimp the lug, then push the heat shrink tube over the lug-wire joint
- Activate this tubing using a heat gun
- Attach the lug to the appropriate battery terminal and secure it using a nut
Lay Out the Wiring Foundation
Once done with the batteries, connect the terminals to positive and negative bus bars to create the circuit’s base for layering other components. Bus bars are connection points for power collection and distribution.
Bus bars
But you can’t connect bus bars directly to the battery pack. You need these components.
- ANL fuse holder with its 300-amp fuse
- Wireless (Bluetooth) battery monitor
- Battery switch
- Red and black cable (2.0 wire gauge)
Wiring Steps
- Connect the fuse holder to the battery’s positive terminal using a red wire
- Use another red wire to link the battery switch to the fuse holder
- Connect the battery switch to the +ve bus bar
- On the battery’s negative terminal, use a black wire (negative cable) to link the battery to the battery monitor shunt
- Connect this shunt to its display using an RJ12 cable, then link it to the negative bus bar.
Remember to use lugs to terminate the wires. So you’ll also need a crimping tool.
Distribution Panel Wiring
If you are familiar with car wire harnesses, you know the importance of a fuse box in the system. A 12V fuse panel is of equivalent significance in a camper’s wiring system. It contains individual fuses that safeguard all connected components from faults like short circuits and ground faults.
A distribution panel (RV fuse box)
You need these components to install a distribution panel.
- Two 2-gauge wires (black and red)
- Circuit breaker (120A)
- 12V fuse panel
- Blade fuses
- Lugs for termination
Wiring Steps
- Connect the +ve bus bar to the breaker switch using a red wire with lugs crimped on the ends
- Link the breaker switch to the fuse panel using another red wire with lugs attached to the ends
- Connect the negative bus bar to the other end of the fuse panel using a black cable with lugs crimped on the ends
- Install blade fuses into the fuse panel slots
Powering Components
The 12V fuse panel contains separate positive and negative terminals that you can use to power and ground the camping equipment.
You need butt connectors to link the device wires to the fuse panel via external extension wires. Also, get ring connectors for attaching the wires to the fuse panel.
Some devices to consider installing are USB charging ports, LED lights, fans, and a water pump to pressurize the water supply lines.
Grounding
Although you’ve grounded the components using the battery’s negative terminal, you should ground the entire system using the vehicle’s chassis.
In most cases, a four-wire gauge is sufficient for this connection, and you should check the specific vehicle type to determine its designated ground points. These distributed points enable you to ground the system from the nearest area.
And grounding only involves connecting the negative bus bar to a chassis ground point using a green wire.
Battery Charging
Battery power is not infinite, and we recommend having a battery pack that can keep you running for at least three days. After that, you need a recharging system.
Let’s assume you want to go completely off-grid. The best option is to mount solar panels on the roof.
Solar
Unlike batteries, you can connect solar panels in series or parallel, but you must have an MPPT charge controller.
This device checks the solar panel output, then compares it to the battery voltage. It optimizes solar charging by matching the two voltages, which increases the current going into the batteries.
A solar charge controller
When wiring these devices, connect the solar panel in series, then feed the positive and negative terminals to the solar charge controller.
Ground this component via the negative bus bar, then supply its power output to the +ve bus bar.
This solar energy will power your devices or charge the leisure batteries when there is excess sunshine or a low load.
Alternator
If you go camping and the weather misbehaves (continuous rainfall or overcast), you will run out of power if recharging using solar. So it is necessary to have a backup system, such as using the vehicle’s alternator.
A car alternator
This generator charges the starter battery by first converting the AC power to DC.
So you can use a battery-to-battery charger (B2B charger) to draw power from the vehicle battery and push it to the +ve bus bar. This power will recharge the leisure batteries as the alternator recharges the starter battery.
But we recommend using this option when driving. Or you can leave the engine running after parking the vehicle.
Electric Hook Up
If you visit campsites with electric hook-up access, you can use AC power from the grid to recharge the leisure batteries using an AC-to-DC converter. Alternatively, you can install an AC circuit in your camper to run mains AC directly.
A caravan electric hookup point
Getting AC Power
Standard household appliances like TVs and fridges need AC power. So if you have them in your camper, you need to get AC output from the batteries, and an inverter should do the trick.
The device draws electrical current from the positive and negative bus bars, then connects to the ground to create an earth terminal for the wall outlet.
A solar panel installation with an inverter
But its AC output should go into a breaker panel to connect to breaker switches before going to the wall outlets.
And instead of having a separate AC-to-DC converter or AC circuit for the electric hook-up option, we recommend buying an inverter/charger to simplify the circuit.
Wrap Up
Wiring a camper begins with selecting the appropriate battery pack size to run your appliances. The more you have, the more batteries you’ll need.
Also, you must ensure the wire gauge is sufficient to handle the electrical load and charging current. But the rest of the other components are the same.
So get started on setting up your camper for comfortable living outdoors. And let us know if you encounter challenges along the way. We’ll be happy to help.
