diy camper electricity

Doing your own electrical systems for your homemade camper isn't as difficult as it might sound -- especially if you commit to keeping it extremely simple!

You can think of an RV or camper electrical system as made up of just three components:

  1. The Battery (a.k.a. the "House Battery", as distinguished from your "starting battery"
  2. The DC Circuits (direct current)
  3. The AC Circuits (alternating current)

Keeping things simple...

I'm sure you know what a lead-acid car battery is, right? OK! You'll need one of those. (There are matters of the best battery type for a camper, but that can wait...)

The DC circuits are those wired to run 12V devices that can run off a car battery, i.e. from your car's cigarette lighter. These circuits are connected directly to the battery, just as your cigarette lighter is wired directly to the battery.

inverterThe AC circuits are those wired to run standard household plug-in devices. If it has a standard plug, then it is an AC device, and it requires an "Inverter" to be placed between it and the battery. The inverter turns standard "flat" direct current into the special"rippling" AC current that household appliances require.

Camper electricity revolves around Battery Powered DC Wiring. While it's in many ways easier for a beginner to implement, it's different enough from standard household wiring that it can be very confusing at first, even for electrical engineers! To help wrap your head around it, a crucial point to "get" is that...

An Inverter Is A DC Device!

(That is used to run AC Devices)

It might be easiest to think of camper wiring as implemented in layers:

First you have DC layer, which at it's simplest is a lot like wiring your speaker system together, or more accurately, like wiring a high-end car audio system. 

  • You first connect a set of cables from the battery to a hub, i.e. set of "distribution blocks." 
  • From there you branch off wires to DC devices like DC fans, LED lights, cigarette lighter outlets for plugging in your phone, AND... an Inverter.

Once you have an inverter connected (to a branch of the DC circuit), you can then plug your AC household appliances (portable fan, clock, heater, coffee maker, mini-refrigerator, etc.) into the inverter. Simple right?

That's really as complicated as it gets, ie. not very complicated at all! 

Interested in making a cheap AC inverter out of parts you can often get for free?

If you happen to have a broken UPS backup computer power system lying around (or can find one cheap), you could possibly turn it into an inexpensive power inverter for your camper.

Uninterruptible Power Supplies are often thrown away or donated to thrift stores when their battery goes bad. Once they do, you could simply replace the dead battery with your RV's deep cycle battery and enjoy a decent quality inverter that often -- at least on newer ones -- includes 5V USB power for your phone -- in addition to several standard AC outlets.

cheap camper inverter from ups

Typical UPS units you find in thrift stores

I actually did this, after watching the video below that I found on YouTube. It's an interesting project. The main idea is simply to unhook the leads going to the internal battery and then solder in some leads that will connect to an external battery. The most elegant solution -- to make it function like a store-bought inverter -- would be to run small leads to screw terminals on the outside of the case.

The second simple bit of electronics is to turn off the emergency alert -- the high-pitched squeal that normally is designed to warn you when the electricity goes out and you're running on battery power -- and you can disable it simply by finding the small buzzer element and cutting the leads and removing it.

There are other hassles you can run into. I found the outside case can sometimes be unreasonably difficult to crack open. You might also find that the circuitry is already fried, or in such bad shape that it sizzles or breaks as soon as you connect the battery. But after a few, you might just find one that opens easily and works really well.

The one big disadvantage for a small camper is the weight -- the transformer inside is quite heavy, especially on large UPS units, and especially when compared to the lightweight transformer-less inverters you can buy on sale for $40-80.

It's also no less prone to shorting out -- A badly-timed surge can fry any inverter pretty easily, so it's nice to have the option to exchange it for a new one. Then again, it's also nice to know you can build one for next to free, so it's well-worth learning how to do it!
(Note: Modified Sine-Wave AC output by cheaper UPS inverters may not be suitable for all devices. For quickly charging your laptop and mobile electronics, it should do fine, but for continuous power, beware that it could cause problems, so be sure to google and download the UPS manual. If you're concerned about this, check out his next series on how to make a sine-wave inverter. )

Watch The Video And Comment Below!