The Camper Van Inverter
At the time there was a lot of discussion, and of course the inevitable calculating, between myself and the Auto-Electrician that I used to carry out the work. Mostly as to which Inverter I was was going to buy, and where it was going to go. These things obviously had to be finalised prior to the work being estimated for then carried out.
My wife was extremely curious as to what we were discussing and asked me to explain exactly what on earth an Inverter was. Coming from an Engineering background, I took it for granted that everyone else would simply know what a Camper Van Inverter was. That proved not to be the case, so here’s the low down on the Camper Van’s Electrical System.
I’m talking about the Electrical Charging System for Petrol or Diesel Vehicles here. I have not yet upgraded my knowledge to “All Electric” Vehicles such as Teslas or the New VW ID Buzz, but I suppose I will have to be pulled into the 21st Century eventually at some time in the near future…
What Is The Difference Between AC and DC Current?
In simple terms, our Car’s systems uses a 12 V DC System, and Domestic Appliances such as Cookers and Fridges use a 230 V AC System. Our Camper Vans have both a Car’s DC Electrical System and some Domestic Appliances, so we will need both.
I was going to go into this AC/DC explanation in depth, but found a video that explains it better than I could, so here it is:
The Normal Vehicle Electrical System Explained (For Comparison)
Our normal vehicles such as Family Cars or Work Vans usually run on 12 Volt Direct Current Systems. The turning of the engine drives a belt connected by a pulley to the Alternator (which is a small Electrical Generator which generally has a Voltage Regulator incorporated in it), which in turn feeds the Electricity that it generates to a Battery (a place to store Electrical Energy). This Battery holds and then supplies the 12 V DC power when demanded to operate everything that is electrically powered in your vehicle, such as Lights, Windscreen Wipers, The Starter Motor and the Radio.
What Is An Inverter?
An Inverter, as used in a Camper Van is simply a device (a box) for changing the 12 V DC Current that we have in our vehicle into 230 V AC Current that we can use in any Domestic Electrical Appliances that we may have in our Camper Vans. Here’s the actual one that I fitted to my Camper Van:
The Camper Van’s Electrical System Explained
Why Do Camper Vans Have Leisure Batteries?
It was found by years of trial and error in the early days of Camper Vans and Motorhomes, that is was beneficial to have 2 completely different Electrical Systems.
The reason for this was that in the days of having just one system, if you too much power on leisure activities such as cooking and boiling kettles, there was no power left to start your vehicle and drive off the next day, as you had used up all the available battery power. Having separate Vehicle Systems and Leisure Systems prevents this from occurring.
As we have now concluded that the Vehicle System and the leisure System are independent of each other, we will now only talk about the Camper Van’s Leisure System.
The leisure system consists of Batteries (to hold the power), An Inverter (to convert that power from 12 V DC to 230 V AC), A Fuse or Circuit Breaker (to prevent any overloads), and a means to recharge the Batteries (actually, several means to charge the batteries).
Leisure Battery Charging can be carried out by either:
- Power from the Vehicle’s Alternator/Generator as the vehicle drives or runs when static
- Power from Solar Panels fitted to the Camper Van
- Power from being connected to a Domestic Electrical Supply by a Cable
- A Combination of all 3 of the above
Here’s a schematic of the Leisure System on a typical Camper Van/Motorhome:
What Type Of Leisure Batteries Are Best For A Camper Van?
The Vehicle System’s Battery is called upon to give a sudden large charge which drives the starter motor in order to start you vehicle. Leisure Batteries, on the other hand give a slow steady charge out over a long period of time and discharge a lot more before needing to be recharged.
Due to the nature of how Leisure Batteries are used as compared to the Vehicle System Battery, Leisure Batteries are of a completely different type, known as Deep Cycle Batteries.
The best type of Deep Cycle Batteries for Camper Vans currently available are Lithium iron phosphate (LiFePO 4) batteries.
LifePO 4 Batteries are self contained units with their own on-board charge manager. Having eliminated the lead content of traditional batteries, they typically weigh half as much as an equivalent lead-acid battery so the weight saving is a major benefit.
LifePO 4 batteries can also be fully discharged and recharged. During the discharge cycle they can also maintain a stable voltage level and they can be rapidly recharged back to full power.
The cost of purchasing new LifePO 4 batteries can be an issue, they typically cost up to five times the price of a good quality lead-acid battery, but they are worth the investment if you can afford it.
I couldn’t afford LifePO 4 batteries at the time, so I fitted the next best thing, 2 x Bosch 100 A/h Deep Cycle, Maintenance Free, Gel Filled Batteries to my conversion, these batteries still cost me £180 each!
Why Do I Need An Inverter In My Camper Van?
The purpose of having an Inverter in your Camper Van is so that you can take the large amount of power that you have available in your leisure batteries, and step it up from 12 V DC to 230 V AC so that it can be used to power your Domestic Appliances, such as the most essential of all Camper Van Appliances, the Kettle, and of course any other Household Sockets you may have fitted.
Once we had upgraded our Camper Van we found that we could run the Aircon (the biggest energy draining appliance) on the lowest temperature for 5+ hours with the engine turned off without running out of Leisure Battery power.
Alternatively, if we had the Aircon off, we could run everything else we needed, overnight, without fully discharging the Leisure Batteries.
What Size Inverter Will My Camper Van Need?
This is a fairly difficult question to answer accurately, as each person, and each Camper Van will have different energy demands. After a great deal of deliberation and discussion with the Auto-Electrician we came up with an energy consumption figure for my Camper Van (Aircon included) of approximately 1200 Watts.
His advice was to get an Inverter that could supply more power than I would need, so I bought a 1500 Watt (3000 Watt Peak) Inverter at a cost of around £230. The 3000 W Peak Value allows for surges in power demand, such as switching on a kettle, from tripping out the Inverter.
The Inverter allowed us to run the Kettle, Fridge, Lighting and Aircon together as well as a bank of 4 x Electrical Sockets that we used to charge phones and plug other things in to.
Here’s the Aircon Unit with the Sockets above it.
What Is A Camper Van Inverter – Summary
Hopefully that has explained exactly what a Camper Van Inverter is, and of course why you need one.
It should have given you a basic understanding of Camper Van Electrical Systems and why there is a need to have two separate systems rather than running everything from the vehicle’s 12 Volt system.
Camper Van Electrical Systems are pretty basic and easy to understand, but if you feel there is anything that you may feel needs clarifying, feel free to contact me and I’ll gladly help out where I can.