Solar Panels for Caravan

So, you’re finally ready to take the plunge and live the off-grid lifestyle.

You dream of days spent traversing Australia in your caravan, experiencing all it has to offer without being tethered to any one place. You want to be able to pack up and go at the drop of a hat.

Well, to make this journey worthwhile, you need to install solar panels on your caravan. They’re your best bet when it comes to electric power.

But you have questions:

  • How do you determine how much power you need in the first place?
  • How do you ensure a smooth installation?
  • What tools and equipment do you need to get this done?

We’ve broken the process down into three simple steps to ensure smooth installation.

Step 1 - Determine How Much Energy Your Caravan Will Need

Before you buy, you must understand the components of a caravan’s solar power system and determine your caravan’s energy requirements.

There are four primary components of a solar power system:

  1. Solar panels: These come in three main types for caravans: glass solar panels, portable solar panels, and folding solar panels.

    The output voltage and wattage will be indicated on the panel’s specifications. You can also connect multiple solar panels to increase the output wattage while keeping the voltage at the same level.

  2. Battery: 12 V deep cycle batteries are the most popular option for caravans as they deliver enough power to keep basic electrical appliances and devices running. We always recommend using Lithium Deep Cycle batteries instead of AGM batteries as it eliminates several issues and they are now actual far cheaper when you look at total cost of ownership. 

    Using High quality solar panels, ideally with a 200W or more power rating will allow you to fully charge a 100-Ah battery in 5–8 hours under ideal weather conditions.

    In rare situations where you find yourself without enough sunlight to charge your caravan’s batteries, you can use a DC-to-DC battery charger to charge them with your car’s alternator.

  3. Inverter: This converts 12 V DC power to the 240 V AC power required to run many electrical appliances in Australia, such as air conditioners, toasters, and microwaves.

    To lower the risk of damaging your appliances, only consider high-quality, pure sine wave power inverters for your caravan.

  4. Solar regulator: This regulates the voltage coming from the solar panels so that the batteries receive just the right amount required to charge them.

The maximum amount of current a regulator can take will be indicated in the specifications. For maximum efficiency you need be using an MPPT solar controller but you can also consider if you can get by with a PWM solar controller which are far cheaper. You can read more about MPPT Vs PWM here but we recommend not skimping on this or you wont be getting maximum charging efficency from your solar panels with a PWM solar controller. 

couple cooking in a caravan

Batteries are rated in amp-hours (Ah) and in theory, a 100-Ah-rated battery can deliver 1 amp of current for 100 hours at 100% efficiency, 4 amps for 25 hours, 5 amps for 20 hours, and so on. However this is not the case for SLA/AGM/Gel that all suffer from the Peukart effect (Peukert's law). Lithium does not suffer the Peukart effect as such due to its low internal resistacne howevert this starts to get pretty complex and requires a another whole article to cover it properly.

Of course, even with Lithium efficiency is never exactly 100% as some energy will be lost through heat and other means. The voltage of an AGM caravan battery also starts to dip as it’s used, and the lower the voltage, the lower the current it generates.

By the time the battery hits 30% capacity, it no longer has enough voltage to power most appliances. If you continue to use your battery beyond this point, you’ll reduce the number of charge cycles you can get out of it. 

Therefore, for the longest possible battery life using SAL/AGM or Gel, most manufacturers recommend staying above 50% of your battery’s capacity. 

So, if your set-up is rated at 240 amps, you’ll only be able to use 120 amps for practical reasons. This is an important consideration when outfitting your caravan with solar power.

Lithium LiFEPO4 is the exception to this which is why they are so popular and the battery we strongly recommend tro everyone.  

To work out your required battery capacity:

  1. Find out or calculate how much current each appliance you plan to use in your caravan draws. This will often be indicated in amps on the packaging, manual, or body of the appliance.

    But even if all you have is a wattage rating (W), divide that by the battery voltage to get the current. For instance, say you plan to use a 1.2-watt LED on a 12 V power source. The current will be 1.2 W / 12 V = 0.1 amps.

    Do this for all your appliances.

  2. Estimate how long you plan to use each appliance each day. For instance, you might use your bedside lights for only 3hours while your small fridge runs nonstop for 24 hours.
  3. For each appliance, multiply the current by the number of hours to get the total current per day. So, if your bedside lights draw 0.03 amps and you have two of them that you use 3 hours each day, the total current per day is 0.18 amps.
  4. Add up the totals obtained so far for all your appliances, if you have used anything other than Lithium batteries you will need to multiply by 2 (to account for the fact that you have to keep the battery above 50%), and that’s how much battery capacity you need to get you through one day.
  5. Finally, multiply the required daily capacity by how many days you want to be able to use your caravan's battery without recharging it. So, say you get a required daily capacity of 26 amps and you want to be able to go 10 days without a charge, you’ll need a battery bank with a total capacity of 260 amps.

This is an oversimplified, back-of-the-envelope calculation but it should give you a rough idea of what your needs are.

two people in a parked caravan

The table below gives a general idea of the energy usage of some common appliances. Don’t just take these figures to heart. Check your appliances to find out what their actual energy usage is.

Appliance Energy Usage
LED lights Less than 0.5 amps/hour
Small refrigerator 1–3 amps/hour
Large refrigerator 3–5 amps/hour
HVAC 60 amps/hour
Microwaves, hair dryers, and kettles 20–50 amps/hour

upgrade your caravan with solar panels

Step 2 - Gather Your Tools and Equipment

The next step is to gather the tools and equipment you’ll need for the installation.

For utmost ease during the installation process, purchase a DIY installation kit, which comes with almost all the necessary parts. A kit like this typically includes:

  • Two solar panels
  • Mounting brackets or adhesive
  • Cables
  • Charge controller
  • Fuses
  • Connectors

Most solar kits don’t come with an inverter or battery, so you’ll need to buy those separately.

However, if you have specific brands in mind, you can purchase every component separately.

As for tools, you’ll need:

  • Screwdrivers
  • Wire strippers
  • A Drill (with two bits)
  • Electric tape
  • Snips
  • A caulking gun

Step 3 - Install Your Solar Panels and Connect Everything

Now it’s time to install and connect everything.

Warning: Before proceeding, you must understand that you’re dealing with electricity. And, as is expected of anything involving electricity, this can quickly become dangerous if you don’t know what you’re doing. In that case, it’s much better to seek the help of a professional than risk injury.

Now that that’s out of the way, observe the following steps for installation. Note that the process is mostly the same whether you have a 12 V or a 24 V system.

  1. Clean the roof of your caravan. Use soap and water to get rid of any oils or persistent dirt. Doing this will allow the adhesive to bond to the roof correctly.
  2. Laying the panels down on a flat surface, apply adhesive to them generously.
  3. Place the panels where you want them on the roof. Be mindful of their orientation. You want them placed squarely rather than askew. Check their position and remove any excess adhesive with a paper towel; then check that the seal all around the panel is consistent.
  4. When the panels bond firmly to the roof, drill a hole in the roof for the wiring. It’s easy to damage the ceiling boards during this process, so get someone to hold a piece of wood to the ceiling on the inside while you drill from the outside. Do this slowly and steadily to reduce the risk of damage.
  5. Pass the wire through the hole and seal gaps with the caulking gun.
  6. Now, install the solar regulator inside the caravan. Connect the regulator to the battery first, then connect the solar panel second. Do this in the wrong order and you risk damaging the regulator.
  7. Finally, test the system. Double-check all your connections first, then turn it on to see if it works properly.

In the video below, you get a detailed breakdown of the installation process:

Upgrade Your Caravan With Solar Panels

And there you have it! Three simple steps for installing solar panels on your caravan hitch-free.

Anyone can install solar panels for a caravan if they have the right tools. But having a professional do this kind of work is always a good idea.

Off Grid Direct gives customers access to renowned solar energy brands such as Victron Energy and Enerdrive. Contact us today at for all your solar needs.

“The kit came in perfect condition, with plenty of wire and was easy to hook up. Would definitely buy it again.”
— Warren Mcgee

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