About inverters

Building my own camper, I learned the hard way about many things I thought I knew. One of them is about the inverter. So here are a few things you should keep in mind when shopping for an inverter for your truck.

First what is an inverter and why would you need one?

There are two sources of electric power for your truck. For now I will leave aside solar panels. One is the 12 Volts from either your vehicle battery or more likely from a secondary battery. The other source is what is commonly referred to as shore power, and that is the 110 or 220 Volts from a campground outlet. It is probable that your camper installation will include items that run off 12V, and others that require 110 or 220V.

Water pumps are usually 12V, and LED lights as well. Fridges, microwaves, toasters, will require 110 or 220V. Electrical installations in RVs and campers are varied and depend on the owners’ needs and requirements. What the inverter does is convert the 12V from the battery to 110 or 220V. This allows you to run your appliances even when not connected to shore power – that is when camping in the wild or while driving, or simply stopped for lunch on the side of the road. If that sounds convenient it really is, but things can get very complicated from there on. Inverters being electronic devices have a number of specifications that you need to be aware of, and understand.

Inverter specs:

Input voltage: 12 Volts within a specific range (ex. from 11V to 16V)

Output voltage: 110V or 220V depending where you live

Output power: will be in Watts, ex. 1000W (peak 2000W). Add the total wattage of the appliances that your inverter will power to find out the “size” of inverter you need. All your appliances have a sticker or label that says for example 110V – 175W. Once you’ve added all the Watts, add another 25% at least for comfort, I would recommend even 50% if you can afford it. You don’t want your inverter to run at full power all the time. The peak rating is exactly that, how much power the inverter can supply in a peak, as when an appliance is suddenly turned ON for example. The physical size and price of the inverter will go up at the same time as the power rating. That means that you should try to reduce the number and size of appliances that you will carry on board. Also shop for more energy efficient units. As a side note a device that converts 110V or 220V to 12V is called a converter, and it basically does the opposite of what the inverter does.

Wave output: There are basically two types of inverters: Modified sine wave and True sine wave. True sine wave inverters produce an output signal exactly like what you get from a home electric outlet, while modified sine wave inverters produce a more squarish signal that is not suitable for all appliances, and will reduce the efficiency of operation of the appliances they power. Of course a true sine wave inverter will cost significantly more but you are guaranteed that all your appliances will work trouble-free. My opinion is that it is worth paying the difference to avoid electrical problems once you are away from home.

Installation and wiring: Your inverter should be wired straight to your auxiliary battery with thick wires. Your inverter might come with 12V hookup wires supplied, and if not then the owners manual will recommend the size of cables to use, as well as maximum length. Inverters have their own fuses built-in and usually user-replaceable.

On the other face of the inverter you will find one or two AC outlets to connect your line(s) to your electric panel and circuit breakers. Make sure the inverter has some space around it for ventilation. Again check the owners manual for recommendations.

Research before you buy, there are many articles online (check this highly detailed article on Overland Site for example), and always purchase from a knowledgeable store that understands your needs.


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