Lesson 4: Power


It is critical to understand power as it relates to your coach. After all, that is the most convenient thing they provide: self contained systems and comforts that all take power to function.

This lesson covers the basics about what you need to know about AC and DC power. There is much more information in the MasterTrack course, but we provide enough here to help you understand and use your coach much more effectively.

Your coach will most likely be a 50 amp coach, meaning that – if plugged into a power source or running the generator – you can use up to 50 amps worth of AC power at one time. NOTE that DC power draw is not included in that 50 amp calculation.

Below is a download of our Amp/Watt worksheet to help give you an idea of what kind of draw different appliances have. After a certain period of time, you’ll learn what you can and cannot run together just from experience. But in the beginning it’s helpful to learn a few basics: Like the air conditioner peaks at 20 amps and settles at 15 amps. That’s very helpful to know!

The worksheet also includes a formula to help you convert between amps and watts, since most of our electronics are measured in watts but our coach is measure in amps!

MasterTrack Lesson

Power management: As an RV’er, you MUST learn about power and understand how to use it. Your house has roughly 200-250 amps. Your coach is 30/50. As you can see, you won’t be able to use your coach like your house.

Coaches contain two kinds of power: AC and DC. AC is what you’re used to using in your house – the regular outlets that you plug things into. DC is what comes from the battery. We’re used to using DC when we use a battery powered flashlight, start our car, or use the phone charger in our car. It is important to know the difference between these two sources, as it will help you best use your appliances and quickly track down issues quickly when they do arise.

In a coach, you only get AC power 4 ways: plugged into shore power, from the generator, from solar, or from the inverter. The inverter turns 12V batteries in 120V AC power. You inverter can be turned on/off. You get DC power directly from the batteries. AC power has breakers. DC power has fuses. AC power is 110/120 volts, DC power is almost always 12 volts. DC amps are measured differently than AC amps. Simply multiply the AC amps by 10 and that will give you the measure of DC amps. This is important because if you have a battery monitor, once you terminate AC power to the coach, you’ll see DC amps now instead.

If you exceed the amp rating for your coach, you will blow a breaker or fuse somewhere. Sometimes you will run appliances you’re used to running, but this time the breaker blows. This is often for one of two reasons: 1) There are things running that you’re not aware of that you forgot about (such as the fridge) or 2) the startup energy needed takes more than steady state does (i.e. fridge compressor or air conditioners first turning on).

Video Lesson


Get the “Amp and Watt” worksheet here!

Download File