What Inverter Size Do I Need

What size of inverter to do you need to power your adventures?


Let's set the scene...

You’re planning your tiny home conversion, umming and ahing about what campervan inverter size you need. We get it, it can feel overwhelming to understand what’s right for you and the last thing you want is to run out of power.

The good news is, we’re here to help with this handy one stop guide to choose the right size of inverter to keep your bread toasting and microwave turning, all day long. Keep reading.

In this blog, we will look at:

  • Factors that influence your campervan inverter size
  • How to calculate your overall appliances usage
  • Introducing you to our handy Inverter Size Calculator
  • Background information on inverters
  • What is a watt? (Sounds daft but it’s very important to understand)

If you would like to skip the reading, you can go straight to our Inverter Size Calculator.

What Size of Inverter Do I Need?

Inverter size is directly related to which 230V appliances you want to use off grid in your campervan. You can size your inverter right now by following 3 steps:

Step 1 – Create a list of all the 230V appliances you want to use with your campervan electrical system. Next to each appliance, write down the watts (W) rating of that appliance. 

Step 2 – Find out the wattage of the highest rated appliance that you plan to use and add a 20% buffer. Write down this value.

Step 3 – Take a total wattage of all your 230V appliances. Write down this value.

QUICK TIP – The Watts (W) rating of most appliances can be found on a sticker on the appliance, charger/power cable or product website page. See a list of common appliances and their wattage below.

What next?

Once all the steps have been completed, you will have two values.

Value 1: Based upon your highest rated appliance 

Value 2: Based upon the total wattage of all your appliances

These two values will inform you on what inverter size you need for your campervan, giving you two options.

Now, lets run through an example…

Example: What Size of Inverter Do I Need?

To calculate what Inverter size you need for your campervan, follow our example below or alternatively use our Campervan Inverter Size Calculator.

In this example we will be looking to use the following 230V appliances off-grid:

  • Hair straighteners – 150W
  • Laptop charger – 100W
  • Blender – 500W
  • E-bike – 600W
Your Options

Following this example will give you two powers (W) to size your campervan inverter. Which one you pick depends on how you wish to use your appliances:

Inverter size 1 – Size your inverter using the highest rated appliance if you only need to use one 230V appliance at a time. Shown in step 2. 

Inverter size 2 – Size your inverter using the total wattage of your appliances if you want to have unrestricted access to your 230V appliances. Shown in step 3. 

We build our kits using Victron components. The Victron Energy Inverter specifications can be found on their website.

Top Tip

Important note: Victron Energy names their inverters using the power supplied under ideal conditions (VA). In reality, the real power output is slightly less than the name. For example, the 800VA Victron Inverter will provide 650W at 25℃.

Using One Appliance Vs Using All Your 230V Appliances at a Time

What campervan inverter size do I need? | Vunked

Using One Appliance at a Time

We recommend sizing your inverter using the highest rated appliances, plus adding a 20% buffer if you would like to keep costs down and want to get as much time off grid as you can. 


  • Keep costs to a minimum by using a smaller inverter
  • By using less appliances your energy consumption will be lower, giving you longer off grid


  • You will have to keep an eye on what 230V appliances you run – if you try to draw more power than your system can handle you will likely blow a fuse

Using All Your Appliances at Once

We recommend sizing your inverter using the total wattage of all your appliances if you are happy spending a bit more money and want to have unrestricted use of your 230V appliances.


  • Able to use all your 230V appliances at once


  • Your larger Inverter will be more expensive 
  • Your system will draw more power so will require a larger battery or charging capabilities to stay off grid
  • As your system is drawing more power you will need thicker cables to handle this which can increase the cost slightly

Calculator: Campervan Inverter Size

Use our handy calculator to find out what campervan inverter size you need straight away. Choose the 230V appliances you want to use in your campervan and we will take care of the rest. 

The calculator results will contain a link that takes you directly to an Inverter system that suits your style of adventure. Our Inverter systems come with all the wires, consumer units, fuses, lugs and heat-shrink you need to install in your campervan.

Alternatively, you can view our Victron Phoenix Inverters as stand alone items. 

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Learning Zone: Inverters

What is an Inverter?

An inverter is a device that transforms DC voltage into AC voltage. Campervan leisure batteries store energy as a DC voltage, either 12, 24V or sometimes 48V. Your appliances that have a UK 3 pin plug (most of them) require 230V AC voltage to run – we call these 230V appliances. An inverter lets you power larger appliances on your adventure. If you want to take a laptop charger, hair straighteners or even a kettle for a cup of tea on those crisp mornings – you will want an inverter.

Victron Energy Phoenix Inverter description

What is a watt (W)?

The watt (W) is a universal measurement for power – more specifically it is energy per unit of time. For those of you that remember physics at school, 1 watt is the equivalent of one joule of energy per second.

All electrical appliances will have a wattage rating. This is an important factor to consider when planning your van build.  By thinking about what appliances you want to use in your van, we can help you build a campervan electrical system that is suited for your style of adventure. 

Build: Inverter Systems

Worried about wire and fuse sizes? Want your Campervan Electrical System to be designed by an expert? Look no durther. All our Inverter Systems come with all the wires, fuses, consumer units, lugs and heatshrink you need to install in your campervan… 

If you already have all the extras, you can buy a Victron Energy Phoenix Inverter own its own.

Learn More

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