Inverter in the motorhome
In this article, we will tell you what an inverter does in a motorhome and for whom it makes sense to install such an inverter in a motorhome.
We will also answer common questions about inverters.
Table of contents
What is an inverter?
An inverter (also known as a voltage converter) converts direct current (DC) into alternating current (AC). An inverter is required in a motorhome as the supply batteries only supply direct current.
Most supply batteries for motorhomes have a nominal voltage of 12V. If you want to convert this voltage to 230V, you need an inverter that is connected directly to the battery.
Who needs an inverter in a motorhome?
In short: Anyone who wants to have access to alternating current (230V) while on the road without being connected to shore power needs an inverter.
An inverter is particularly recommended for self-sufficiency enthusiasts who do not want to miss out on the luxury of operating appliances that require alternating current.
Classic examples of appliances that are operated with alternating current:
- Hair dryer
- Blender
- Kettle
- Electric grill/sandwich maker
- Coffee machine
- Electric hotplate
How much power should the inverter have?
There are inverters with different outputs. The power of an inverter is measured in watts and indicates how much electrical power the device can convert.
Most inverters for motorhomes have an output of between 500W – 3000W.
How much power you ultimately need depends entirely on you. First and foremost, you should look at the devices you would like to operate in the motorhome and work out the power required. If you want to operate several devices at the same time with 230V, you need to add up the required power.
Please note that most appliances have inrush or starting currents. This means that when the appliance is switched on, starting currents flow which may be many times the rated current. Information on this can be found in the operating instructions for the appliance.
Due to these high starting currents, inverters not only have a constant continuous output, but also the function of delivering a significantly higher peak output in the short term.
Network priority circuit - what is it?
A mains priority circuit ensures that when connected to shore power at the same time, the inverter only uses power from the connected mains instead of the connected battery.
Modern, high-quality inverters have this mains priority circuit integrated into the device. If there is no integrated mains priority circuit, an external mains priority circuit can also be integrated into the power circuit.
A mains priority circuit is not absolutely necessary. However, if you are often connected to shore power, this can be a very practical aid.
Pure sine wave vs. modified sine wave
Inverters are available with either a pure or modified sine wave – but what is the difference?
Pure sine wave
An inverter that generates the output current with a true sine wave voltage gives a high-quality output current that is comparable to the usual mains current.
This is particularly important if you want to operate or charge sensitive electrical appliances. These include, for example
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- Laptop
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- Television
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- Coffee pod machines
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- Chargers
Laptops in particular can be damaged if they are not charged with a pure sine wave.
Modified sine wave
With a modified sine wave, the output current is modeled in a kind of “staircase shape” and is not nearly as “smooth” as with the pure sine wave.
With simple electrical appliances, it does not make much difference which sine wave is present. These electrical appliances also work quite well with the modified sine wave. Examples are
- Kettle
- Toaster
- Shaver
- Blender
- Vacuum cleaner
Connecting the inverter in the motorhome
In principle, it is not difficult to connect an inverter in a motorhome as long as you pay attention to a few essential things during installation. Make sure you read the enclosed operating instructions carefully before installation.
The right battery
It is very important to ensure that the supply battery to which the inverter is to be connected can withstand the current of the selected inverter. You should definitely check the technical specifications of your battery.
Example: You have a supply battery that only allows a continuous discharge of 100A and want to connect a 2000W (12V) inverter to it. This inverter would draw approx. 160A from the battery under full load and severely damage the battery if it does not have a good BMS.
Installation location
As a lot of current can flow from the supply battery to the inverter, it should be installed as close as possible to the supply battery in order to keep the cable path short. As an inverter can become hot under load, sufficient space should also be provided around the device. Larger inverters also have active cooling.
Cable thickness and fuse
The correct cable thickness is very important when connecting the inverter to the supply battery. Under no circumstances should you use cables that are too thin. The risk of a cable fire would be high. Of course, a fuse is also required between the battery and the inverter.
The required cable cross-section depends on the current flow and the length of the cable. The recommended cable thickness and fuse can be found in the operating instructions for your inverter.
We also have our own cable cross-section calculator programmed. Have a look here:
Power consumption
Such an inverter naturally also needs electricity itself to fulfill its task.
Quiescent current
As long as the inverter is switched on, it consumes a constant quiescent current, which can drain your battery in the long term. For this reason, the inverter should always be switched off when not in use.
If you install your inverter in a place where you cannot easily access the device’s mains switch, a remote control is an advantage. This allows you to install the remote control in an easily accessible place to switch the inverter on and off more easily.
Exchange loss
In addition to the quiescent current, the actual power consumption lies in the conversion itself. Inverters can never convert 100% of the energy they are supposed to convert. The efficiency of most inverters is between 85 % and 90 %. This means that approx. 10-15 % of the energy is lost during conversion.
This is not exactly a small amount and you should be aware of this. Especially with regard to the selection of the supply battery.
Inverters from Supervolt - 2000W & 3000W
At Supervolt, we offer an inverter with a total of 2000W continuous power and 4000W short-term peak power.
Our inverter is sufficient for the vast majority of campers. With 2000W, you can easily operate standard coffee machines, televisions, hot air dryers and more. Even induction hotplates up to 2000W are no problem.
All the advantages of our 2000W inverter at a glance:
- 2000W continuous power - 4000W short-term peak power
- Integrated mains priority circuit
- Remote control with display included
- Pure sine wave - Highest power quality even for sensitive electrical appliances
- Two fans with multiple control (temperature and load)
Need even more power? How about a 3000W inverter? This can even provide 6000W peak power at short notice.
