Campervan Electrics – A Simple Guide

Campervan Electrics

Understanding, Using and Charging your Motorhome or Campervan Electrics

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One of the biggest things you have to get right when you buy, maintain or convert a motorhome or campervan is its electrical system.

Your motorhome or campervans leisure system electrics are used to power:

  • Lights
  • Water Pump
  • Spark to light a gas fridge
  • 12v Compressor Fridge (if installed)
  • Charge up mobile devices
  • Power the ‘blown air’ for gas blown heating or diesel heating depending on which you have installed
  • Electric step (if installed)
  • 12v TV 

So, if you’re not plugged into electric hook up (EHU) and your battery is dead then you’ll have no heating, lighting, water, power to mobile devices and even the spark to light a fridge on gas requires electricity.

And we can tell you, from bitter personal experience, that campervanning without the above amenities is not much fun, particularly in the middle of winter!

So, without further ado, here is our simple guide to understanding your campervan electrics!

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    Common Motorhome & Campervan Electrics Terms

    A Watt is the rate of consumption (or generation) of power.

    A Volt is, basically the pressure, like water pressure, but for electricity.

    An Ampere, commonly known as an Amp, is a unit of constant electrical current. You can calculate an amp by dividing the wattage of a device by the voltage. 

    For example, a 10 watt light bulb on a 12 volt system requires 0.83 amps per hour to run (10 divided by 12).

    A Leisure Battery is your power source for everything that runs in the habitation part of your motorhome or caravan, commonly measured in amp hours and delivers supply at 12v.

    Electric Hook Up (EHU) is when your van is plugged into the mains, this will commonly re-charge your battery and allow you to run 240v devices in your van. You can do this on some campsites, some aires and at home. 

    An Inverter essentially converts your leisure battery from a 12v system into a 240v system. This is a very power hungry way of doing things and will run leisure batteries flat in a very short space of time. Not commonly installed on commercially built vehicles and not usually required. More on this later. 

    12 volt vs 240 volt

    motorhome electrics

    Any power hungry devices in your home will require a 240v electricity supply – not available in a campervan without using an inverter. Some examples of these include:

    • Laptop
    • Air Fryer
    • Electric Grill
    • Kettle
    • Microwave
    • Hair Dryer
    • Hair Straighteners
    Typically, any device that plugs into the wall using a 3 pin plug uses a 240v supply. Anything that uses a usb will be able to work off of a 12v supply. 
     

    Your motohome or campervan will, in all likelihood, have usb sockets, which you can use all the time, and 3 pin plug sockets which will be dead unless you are on EHU. 

    A lot of companies now make and market 12v versions of the above, but honestly, don’t waste your money. They’re rubbish, a 12v kettle will take approximately 20 minutes to boil… Just use gas.
     

    The exception to the rule is you can now buy battery powered hair straighteners and, whilst we’ve not used them ourselves, they do have some pretty good reviews – check it out here.

    Campervan Leisure Batteries Explained

    Not all campervan leisure batteries are made equal. But that’s ok depending on your requirements and budget. 

    Typically leisure batteries will provide 60 to 150 amp hours worth of electricity, most vans these days will have a 100ah battery. 

    We will discover how you can calculate your usage later on this article if you’re not sure how much power you will typically use. 

    Lead Acid

    Lead Acid batteries are the cheapest leisure batteries, but also provide very sub optimal performance. 

    Good if you always use EHU with very occasional offgrid use and are on a tight budget. 

    • 50% usable power (a 100ah battery will only provide 50ah of power even when fully charged. Easily damaged if overused.)
    • Give off gas – need to be stored in an appropriate container and location
    • Heavy, 20 to 25 kgs typically
    • 100 – 200 cycles per lifetime
    • £100 – £200

    AGM

    AGM batteries are the ‘middle of the road’ leisure batteries, better than lead acid, not as good as lithium, and price-wise sit in the middle.

    Good if you often use a mixture of EHU and offgrid but aren’t too power hungry in your usage. 

    • 50% usable power
    • Give off gas – need to be stored in an appropriate container and location
    • Heavy, 15 to 20 kgs typically
    • 200 – 400 cycles per lifetime
    • £150 – £300

    Lithium

    Lithium batteries are the undisputed champions of leisure batteries but have the price tag that goes along with that.

    Good if you are mainly offgrid or wild camping in your motorhome, they can be linked in series to provide more power reserves.  

    • Up to 100% usable power
    • Don’t give off gas
    • Light, 10 – 15 kgs typically
    • 3000 – 5000 cycles per lifetime
    • £600 – £1500

    Campervan Leisure Batteries Summary

    It’s very much worth looking at your leisure battery(s) and finding out what type of battery it is, as well as it’s storage capacity (e.g. 100ah). 

    So hopefully you now have an understanding of each type of motorhome leisure battery available and can start to think about how each type might be suited to your needs. Which is where we are conveniently headed next. 

    Using Your Campervans Electric Leisure System

    So, as we went through at the start, anything in the leisure/habitation side of your camper that requires power will run off of your leisure battery or EHU.

    If you only use EHU then you don’t really need to bother calculating your power usage as it will be powered straight from the mains. 

    Which Motorhome sockets can I USe?

    Your motohome or campervan will, in all likelihood, have usb sockets, which you can use all the time, and 3 pin plug sockets which will be dead unless you are on EHU. 

    Calculating Your Power Requirements

    Take a look at the table below:

    Each electrical appliance in your van will have an associated wattage as seen in the example below. We can use this along with the hours used per day to work out how many amps each appliance requires.

    Totaling this up we can see that the example below uses 27 amps per day in the summer, and 50 in the winter.

    Calculating Campervan Electric Usage

    So, on a 100 amp lithium leisure battery you’d need to charge, pretty much daily in the winter, and every three days or so in the summer. 

    However, if using a 100ah lead acid battery, you would need to charge every single day in the winter and every other day in summer.

    You can access a copy of the spreadsheet using the battery icon above to play around with the numbers and calculate your own energy consumption to figure out how large a battery you need and what charging solutions you’ll need (more on that shortly).

    For your interest we have put our power consumption into the spreadsheet below and we use hardly any electricity. We can get by for five or six days in the winter without charging up.

    Our Campervan Electric Usage

    In reality, we can charge roughly 50% of our batteries capacity every single day without even trying – so never need to plug into EHU!

    We’ll explain how in due course… 

    Do you need an Inverter in your campervan?

    For most people – the answer will be no.

    You only need an inverter if you need to power devices that require a 240v power supply whilst on the road and not plugged into EHU.

    So if you’re happy to go without a 240v supply whilst your on the road, or you can save your 240v devices for when you are plugged into EHU, then you won’t need one. 

    If you do require one, you’re going to need space for several batteries (and the inverter itself). We’re talking 200 or even 300 amps worth of batteries installed, and you’re going to need some serious power generation on board.

    Happily, we’ll discuss how you can achieve that next!

    Charging Your Campervan Electrics

    campervan solar panel

    Now that we know all the common terms used to describe campervan electrics, we’ve learnt about the different types of leisure batteries, we have calculated our power usage all that’s left to know is how can we re-charge our campers leisure battery. 

    Solar Power

    In essence, Solar Panels sit on the roof of your van and charge your leisure batteries whenever the sun is out. 

    The best setup is to have your solar panels charge your battery through a smart controller. This will optimise the power that your solar panel can generate, protect your battery as well as provide you with information on the charging status and speed.

    Solar panels aren’t all made equal, some types are far superior to others, and none will generate a huge amount of power on a typical UK winters day (this is beyond the scope of this article). Even a sunny day during the winter your solar will struggle to generate much power due to the sun being so low in the sky. 

    Below is some very rough numbers on how much energy you can expect to accrue via solar panels in the UK. This obviously varies hugely depending on:

    • How clean the solar panels are

    • If you have a smart controller installed

    • The type of solar panel installed

    • The weather

    Solar Panel Watts Amps Generated Per Day [Summer] Amps Generated Per Day [Winter]
    100 45 7.5
    200 90 15
    300 135 22.5

    Battery to Battery Chargers

    Simply these devices take ‘spare’ electricity from your alternator when the engine is running and pump it into your leisure battery.

    If you run a power hungry setup or have lots of devices to charge then a good battery to battery charger is a must, particularly in the winter when solar will struggle to generate meaningful electricity. 

    Setup correctly you can easily charge your batteries at a rate of 50 amps per hour! Refer back to the tables above and you’ll see just how effective these devices are at keeping you topped up. Particularly in the winter months. 

    Electric Hook Up

    The simplest form of charging your batteries. Simply take an EHU lead, plug one end into the mains, and the other end into your van. 

    Typically this will provide you with 16 amps of power. So say you are using on average 2 or 3 amps per hour, your battery will charge at approximately 13 or 14 amps per hour. So a 100ah leisure battery could be charged from 0% to 100% in as little as 8 or so hours. 

    You can stay plugged in even when you are fully charged as your van will protect your battery from overcharging (providing it’s been installed correctly) and you will have access to 240v power for the remainder of your stay.


    Warning

    Coiled EHU cables get hot and can melt and cause fires. Always fully unravel your EHU cable prior to use. 


    Electric Hook Up abroad

    Electric Hook Up whilst touring abroad in places like France, Germany, Italy and Spain is by and large the same as in the UK with three key differences

    • The amperage provided could well be lower than you’d expect in the UK. In the UK an EHU point will provide 16 amps of power. Meaning you can draw up to 16 amps at time. Abroad this can be 10 or even as low as 6. So bare this in mind and don’t use too much at once. Take a look at the previous spreadsheet to calculate how many amps you might draw at any one time. 
    • Ensure that you have a long EHU cable. Often times, particularly on aires, stellplatz and sostas you may have to park a fair distance from the EHU point. 
    • Ensure that you have a two pin connector with you as well. In our experience most places in Europe use the same bollard style connection as us but there is on occasion a two pin adapter required. 

    Tips & Tricks For Making The Most Out Of Your Motorhome Electrics

    Lighting

    Make sure all of your lights have low wattage LED bulbs – take a look at the difference it can make below:

    Light Watts Hours Amps Used
    Living Room 10 6 5
    Kitchen 10 2 1.6
    Bathroom 10 1 0.8
    Bedroom 1 10 1 0.8
    Bedroom 2 10 1 0.8
    Total 50 11 9.1
    Light Watts Hours Amps Used
    Living Room 40 6 20
    Kitchen 40 2 6.6
    Bathroom 40 1 3.3
    Bedroom 1 40 1 3.3
    Bedroom 2 40 1 3.3
    Total 200 11 36.6

    As you can see by simply changing over to low wattage LEDs you can save in the region of 25 amp hours per day. That’s a huge saving for very little cost or effort. 

    Also consider some battery powered string fairy lights for use in the evening when full lights aren’t required. 

    Power Banks and Power Stations

    Another great tip is to carry portable power banks with you as brilliant, low cost ways to charge your phones and tablets etc. 

    You can charge these little devices very easily whilst driving or if you are out in  pubs and cafes. 

    We also carry a 500w Jackery Power Station which we have done a full review of here.

    Yes, it was expensive, yes it’s basically a small leisure battery. But, it has a built in inverter allowing you to temporarily use 240v devices without having the cost and hassle of installing a full on inverter in your campervan.

    We use ours to charge our phones, tablet and laptop and it easily manages for a week or more before it needs charging up itself.

    If you think you might need 240v on occasion or don’t have enough juice in your leisure battery to charge phones and don’t want the hassle of having to upgrade your leisure battery and inverter right now it really is a great option. 

    Insulation

    Why are we talking about insulation on a post about campervan electrics?

    Well, one of the big power draws will be your diesel heater or gas blown heating. So some good insulation and silver screens can really bring down the number of hours you might run the heating for in the winter. Bonus savings on gas or diesel. 

    If you want to know more about keeping warm in your campervan or motorhome then check out our dedicated post. 

    Essential Gadgets for Using and Maintaining your electric system

    25m Long EHU Cable

    3 Pin EHU Connector

    Mobile Powerbank

    2 pin european ehu connector

    Jackery Mobile power station

    Emergency Head Torch

    Campervan Electrics - Not all that complicated after all!

    So, hopefully you now have a firm grasp of the basics of motorhome and campervan electrics.

    From the terms thrown around, the leisure battery options, calculating how much power you need to store and how to successfully recharge your leisure batteries in a way that suits you.  

    Go Explore!

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