Caravan Solar Power - How Much Do You Need?

How Much Solar Power Do I Need for My Caravan?

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One of the biggest factors that makes for successful Free Camping is a good quality solar set-up.

When asking yourself, “How much solar do I need for my caravan?” you will need to consider:

  • Which appliances do I want to power?
  • How many people will be using the caravan?
  • How much space have I got on the roof for solar panels?
  • How much payload have I got available for batteries?

Since I’m not that savvy with solar power, I called in the experts at EcoFlow, who were able to answer some questions and provide more understanding around caravan solar power.

Whether you want to set your caravan up for weekend camping trips or travel off-grid full-time, here’s a good beginner’s guide to solar power for caravans.

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What Makes Up a Caravan Solar Power System? 

When designing your ideal solar set-up for your caravan, the first thing you need to do is determine the necessary components. Below, we cover the essential items you’ll need in order to get your solar system up and running. 

Gwydir Riverside Camping, Bingara NSW
Caravanning off-grid at Bingara, NSW

Solar Panels

This is an obvious one. Solar panels are essential in order to capture sunlight and convert it into electricity. 

However, choosing which solar panel is right for you can get a little bit more complicated than that. Let’s get into some things you’ll want to consider when it comes to selecting your ideal solar panel.

Types of Solar Panels

There are three main types of solar panels that you’ll hear about:

  • Thin-film
  • Polycrystalline
  • Monocrystalline 

Thin-film solar panels aren’t as powerful or efficient as the other main types of solar panels you’ll encounter, but their flexibility and other qualities make them useful in some scenarios. 

When it comes to monocrystalline versus polycrystalline solar panels, as their names imply, polycrystalline panels are made from many silicon cells, while monocrystalline panels are made of a single silicon cell.

How does this make a difference in application, though? 

Well, making polycrystalline solar panels are less costly, meaning that they are cheaper than monocrystalline panels. However, monocrystalline panels provide several advantages in exchange for their higher price tag, one of them being higher efficiency ratings.

These higher efficiency ratings mean that your monocrystalline solar panels will generate more electricity than their polycrystalline counterparts, allowing you to better maximise your available space and electricity generation. 

Of course, when you’re in a caravan, space is at a premium, and you want to make the most of every bit you have, meaning that it’s often worthwhile to go for the higher efficiency option.

Thin-film✔️ Flexible
✔️ Lightweight
❌ Less efficient
❌ Shorter lifespan
Polycrystalline✔️ Cheaper❌ Less efficient
❌ Lower heat tolerance
❌ Require more space
Monocrystalline✔️ Highest efficiency
✔️ Higher heat tolerance
✔️ Less panels required
✔️ Longer lifespan
❌ Most expensive

Solar Panel Installation

Are you going for a portable caravan solar power installation or a more permanent one? This is an important question to ask yourself when selecting the solar panels for your needs.

Portable panels are made to be easily set up and are well-suited for on-the-go, but you won’t be collecting as much power from the sun than if you had permanent panels on the roof.

If you don’t use a lot of power and are happy to set up camp and charge up when you stop, then a portable solar panel just might do the trick.

Most caravans these days come with at least a basic solar set-up with one or two panels on the roof, which is the most convenient way to keep the batteries charging.

Rigid solar panels are better suited for permanent installation, with sometimes a flexible solar panel to take advantage of irregular or curved surfaces. 

Power Needs

Another thing you’ll need to consider is how much power you require for your needs.

Solar panels come with a specific rated power, which is a measurement of how much electricity they can generate under ideal conditions. For example, a 400W solar panel can generate up to 400W of electricity but will rarely reach that number as ideal conditions aren’t often found in the real world. 

Still, this is a helpful metric to guide you in choosing the right solar panels for your needs. The higher a solar panel’s rated power, the more electricity it should generate.

Of course, you’ll only have a limited amount of available space on your caravan roof, so that will play a large factor in the type and size panels you’re able to install.

Our caravan had 3 x 150 watt permanent solar panels on the caravan roof (totalling 450 watts).

Battery Storage

Battery Set-up
Solar battery storage

Once you have the solar panels selected, you have a method to generate electricity, but you will need somewhere to store that power.

A solar battery stores your excess generated electricity for use when the sun isn’t actively shining, such as at night. This way, your panels can generate electricity all day, and what you don’t use during the day can keep you comfortable and powered throughout the night.

Our caravan had 3 x 110ah Lead Crystal batteries (totalling 330 amp hours)

Batteries can be really heavy, so it’s important to know your available payload allowance before loading up the caravan with lots of extra weight.

As you’ll see below, lithium batteries are the lightest, which makes them the most popular battery choice for caravan solar power set-ups.

Three types of deep cell batteries for caravan solar power storage:

  • AGM
  • Lead Crystal
  • Lithium
AGM✔️ Perform better in cold conditions
✔️ Cheap
✔️ Reliable
❌ Heavy
Lead Crystal✔️ Higher efficiency than AGM
✔️ Charge faster than AGM
✔️ Similar discharge depth to Lithium
✔️ Cheaper than Lithium
❌ Heavy
Lithium✔️ Highest efficiency
✔️ 50% lighter than AGM & Lead Crystal
✔️ Longer lifespan
✔️ Deeper discharge depth
❌ Most expensive

Other Components

Enerdrive Multi-bank Battery Charger
Multi-bank Battery Charger

An important component you will most likely need is an inverter, which transforms the DC electricity generated by your solar panels into AC electricity that is used by most household appliances. This is what you’ll plug things like the washing machine and laptop charger into.

Another essential item for your caravan solar set-up is a regulator to ensure your battery is charged properly and isn’t damaged from overcharging or over-discharging. 

Additional Caravan Solar Power Components:

  • Battery Charger – automatically chooses the best power source (when switching between powered sites & off-grid)
  • Inverter – for plugging in 240v appliances & devices (e.g. laptop & washing machine)
  • Battery Management System – to keep an eye on your battery levels
  • External Andersen Plug – if you want to plug in an additional portable panel

The additional components you need will depend on your specific setup, which your solar power installer can work out and advise you on.

Extra solar power components in our caravan:

Redarc BCDC 1240D 3-stage Battery Charger
• 60 amp Enerdrive Multi-bank 3 stage Charger (for when plugged into 240 volt only)
• 350 watt Redarc Inverter
• BM-1 Battery Management System with digital gauge
• External Andersen Plug
(components can be found on eBay)
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How Do I Calculate Solar for my Caravan?

Battery Management System (monitor)
Battery Management System

If you want to use solar in your caravan, it’s essential to make sure that your system is up to the job of providing the necessary power.

Here’s how to calculate how much solar you’ll need for your caravan.

Calculating Electricity Consumption

To determine how much electricity you need your panels to produce, you need to first calculate how much electricity you’ll consume.

You can do this by determining what appliances and electronics you hope to power with your system, finding out how many watts each device requires, and calculating how much each device will run. 

If you only have the power requirements in amps or volts, you can calculate watts using this formula: 

  • Volts (V) x Amps (A) = Watts (W)

Once you have listed your appliances, how many hours you use them for daily, and their running watts, you can use this information to determine how much electricity you need your system to produce. 

Your next step is to calculate the consumption of each device by multiplying its running wattage by how many hours you’ll use it per day.

That’ll give you the Wh (watt-hours) the device will consume per day. Then, divide by 1,000 to get the kWh (kilowatt-hours) it’ll consume daily.

You have a coffee maker that takes 1,000 watts to run that you’ll use 15 minutes per day.

Use the following equation:
1,000W (watts) x 0.25H (hours) = 250Wh (watt-hours)

Now, divide that by 1,000, and you get 0.25kWh (kilowatt hour).

→ The coffee maker will consume 0.25kWh of electricity daily. 

You can go through this process with all of your devices and appliances and add all of the amounts together to get your daily electricity use.

Or, if this is all just too confusing (I’m with you there!), then you’re best off talking to a professional caravan solar power installer and working out your requirements with them.

Required Power Output

Your electricity usage isn’t all that you need to think about; you also need to ensure that the solar generator you choose is up for the task.

When calculating how much electricity you need your caravan solar power system to produce, it’s important to note the difference between starting watts and running watts.

Difference between Starting Watts and Running Watts:

  • Starting Watts – how much electricity the device needs to power on
  • Running Watts – how much electricity the device need to run

This is an important difference because some appliances require a higher amount of electricity in order for them to start up.

For example, a washing machine might use 1200W when running but could need 2300W to start up. Make sure to factor in starting wattage when calculating how much AC output you need.

How Much Solar Do I Need to Travel Permanently Off-Grid? 

The amount of solar you need to travel off-grid permanently varies drastically based on how much power you’ll be using.

This could be impacted by the size of your caravan, how often you use your devices, the types of devices you use on a daily basis, and more. 

The method outlined above is a great place to start to determine how much solar you need to permanently travel off-grid in your caravan.

Calculate how much electricity you plan to consume in your caravan, and make sure your solar batteries have the necessary output capacity to manage all of your appliances.

Also, keep in mind the limited space that you have on your caravan roof for solar panels, plus space in your tunnel boot, under the bed or under the dinette seating to store multiple batteries.

Make the most of your available space by opting for high-quality panels and batteries with good efficiency ratings, so that you don’t need as many of them.

We lived permanently off-grid in a caravan as a family of four, charging laptops, tablets, phones and cameras every day. In addition, I ran the washing machine most days through the 350 watt inverter.

We did need to be mindful and conserve power during overcast and shady times, but we never ran out of power.

Our Solar Set-up:
• 3 x 150 watt Solar Panels
• 3 x 110ah Lead Crystal Batteries
• 3-stage Battery Charger
• Multi-bank 3 stage Charger
• 350 watt Inverter
• Battery Management System
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How Much Solar Do I Need for My Caravan?

Andrew Drynan Park, Running Creek QLD
Portable panels are optional

Here are some common questions when considering how much solar you might need for your caravan.

What Size Solar Panels Do I Need?

As mentioned earlier, solar panels have a rated power that indicates the maximum amount of electricity they can produce (in ideal conditions, which you’ll rarely encounter in reality).

The higher the rated power, the more electricity your panels will produce. You’ll need to consider the size of your caravan when choosing the right solar panel size for you.

The higher the rated power, the better, as this helps to maximise your electricity generation in relation to how much space you have available for solar panels.

150W & 200W solar panels are common for caravan solar power in Australia.

How Many Solar Panels Do I Need?

The number of solar panels you need depends on several factors, including: 

  • The size of your caravan
  • The size of your solar panels
  • The rated power of your solar panels
  • Your electricity consumption
  • Peak sun hours

Peak sun hours refer to how much sunlight you’ll receive in your location, and it’s an essential factor in determining how much electricity your solar panels will produce.

Typically, a solar panel suitable for a caravan will capture in the range of 100W – 400W of solar power in peak sunlight. By opting for solar panels with a greater rated power, you can make the most of the available space on your roof.

2 – 4 solar panels are common for caravan solar power in Australia.

Do I Need a Portable Panel as well as Roof Panels?

If you’ve got a good permanent solar set-up, then there’s no reason to carry a portable panel as well.

However, some people choose to do so just so that they have the ability to chase the sun with an extra panel if your roof panels end up being in the shade for hours on end.

Another benefit for carrying a portable panel is being able to plug it into the car to keep the auxiliary battery topped up for the car fridge/ freezer (if you have one).

You don’t need a portable panel unless you want to use it to top up the car fridge battery or add a bit of extra charge into the van when cloudy/ shady.

How Much Battery Storage Do I Need? 

The amount of battery storage that you need depends heavily on your average electricity consumption and what appliances you want to be able to power.

Someone who’s charging laptops and camera batteries a lot will need more battery storage than someone who’s just using the LED lights and charging a phone.

How Much Solar to Run a 12v Fridge?

Let’s say your fridge uses 100W to run, and you run it 24/7.

That means it would use 2.4kWh in a 24-hour period.

Based on the rated power of your solar panels and how many hours of peak sunlight you get per day, you could calculate how many solar panels you would need to keep your refrigerator running around the clock. 

How Much Solar to Run a Caravan Air Conditioner? 

Let’s say your air conditioner has an average running wattage of 600W, and you run it for 12 hours a day.

In that case, you’d need to generate 7.2kWh daily to run your air conditioner.

How many solar panels and battery storage this would take depends on the amount of sunlight you’re able to receive each day and the rated power of your solar panels.

EcoFlow Solar Generator
Solar Generator →
Most caravan solar set-ups won’t be able to generate enough power to run the air conditioner. You will need to be plugged into 240 volt power such as at a caravan park, or use a generator.

What Size Inverter Do I Need for Using Appliances?

Once you’ve determined your wattage, it’s a good idea to add an extra 20% to make sure you have additional capacity over the cut-off point.

So, let’s say you need 2,000 running watts – you don’t want to forget those pesky surge watts.

If you need 3600 surge watts to get your appliances turned on and operating, add an extra 20% by multiplying that number by 1.2.

That would give you 4,320 watts. In this case, you’ll want at least a 5,000-watt inverter. 

My 350 watt inverter was powerful enough to run the 3kg Sphere RV washing machine.

What Size Inverter Do I Need for Charging Devices? 

You’ll want to use the same formula outlined above for determining what inverter you’ll need for charging devices. If you’re using devices that have a lower watt requirement, that will result in you not needing an inverter with as big of a watt requirement. 

Phones will generally charge off a standard caravan solar set-up (1 battery and 1 solar panel).

To charge a laptop, you’ll need an inverter to plug the 240 volt cable into, plus extra battery storage for the larger draw.

What Happens When You Want to Hook Up to 240-Volt Power? 

If you want to hook up your caravan to 240V power, make sure your balance of system is rated for 240V. If your solar power system supports 240V AC or DC charging, it’s no problem to plug it in.

Our Enerdrive Multi-bank 3 Stage Charger automatically selected the correct power source for us.

How Long Will My Solar Last on Overcast and Rainy Days? 

How long your solar will last when there isn’t sunshine for your solar panels to convert into electricity depends on factors like how large your battery capacity is, how charged up your batteries were, how much electricity you’re using, and more.

However, the good news is that your solar panels still generate electricity in rainy or cloudy conditions! 

Always keep an eye on your battery management system on rainy days to watch your battery capacity. You may need to be more conservative with your power consumption until they’re able to get a good charge again.

Can I Install Solar Myself, or Should I Hire a Professional? 

It’s possible to install your solar setup yourself if you have a good understanding of solar electricity.

However, to ensure proper installation and have peace of mind that you won’t be stuck in the middle of the outback with no power, it’s always best to hire a professional. 

There is a lot to know in the world of solar, and it can quickly become technical. Hopefully this guide has given you a helpful framework to start delving into the world of caravan solar power and learning more about how it works. 

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2 thoughts on “How Much Solar Power Do I Need for My Caravan?”

  1. Another advantage of having a portable solar panel / blanket …
    we recently managed to discharge our lithium batteries to the stage they put themselves to sleep. [an automatic response once discharge has reach a set low voltage.]
    When I plugged in a battery charger, intending to recharge said sleeping lithiums, the batteries effectively told the charger “there are no batteries here !” so the charger didn’t get a signal to begin charging. In a somewhat anxious state of mind [our van has an electric powered lift & lower capability thus rendered inoperable], I plugged a solar blanket into the anderson plug on the drawbar. The blanket has no controller so as soon as it started collecting sunshine it pushed it out to the isolated batteries that basically awoke and allowed us to finish packing up and closing the pop-top.

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