RV Power Basics #2

120 V and 12 V

All RV’s now come with 120 and 12. 120 volt means that 120 volts of power is provided from an outside source you have plugged in to (Campground pedestal or home etc.) 12 volts means that you are using Battery power from your house battery.

Volts are equal to force. Volts are the force pushing through the lines to power your RV. If you have 120 Volts the potential power pushing through should be 120 (Note: some people say 120 and some say 110 these are basically the same. For simplicity 120 is the main voltage to be concerned with).

AC and DC

No, I am not talking about the rock band. AC is alternating current and DC is direct current.

AC is alternating because inside the line the power is moving from one end to the other and then back again in circuit. AC is more commonly used in 120 V and outside plug in sources. 120 volts will power air conditioners, microwaves, heaters and basically anything that has a higher output.

DC is direct because it flows directly forward and is constant. DC current comes from batteries. Given this, a 12 volt system is the power system that runs on your battery. The most common items that run on this system are lights, motors, electric jacks, slides and most built in generators.

Amps volts and Watts

Watts are a measure of power. Amps are a measure of current or the volume of current and again volts are a measure of force pushing the current.

Volts x Amps=Watts

Or the amount of current (Amps) x force of current (Volts) equals the amount of power (Watts). 
This given, the more amps or volts there is, the more power you have.

An important measurement to calculate, is the wattage of your appliances and to figure how many and when to run according to the amp of your rig (This is more important with the use of 30 amp coaches).

If you want to calculate the wattage total for your RV appliances, you can find wattage located on most appliance nameplates or in the owner’s manual. Wattage can also be estimated by using some online wattage tables for RV appliances (But these are only estimates so be careful in your trust). If you are running 30 amp it may good idea to take inventory of your total wattage and know what appliances to run and when.

1 amp = 12 W

Watts= amps x volts (120)

50 and 30 amp

When plugging in the 4 prong cord, the cord has ground, a neutral () and TWO 120 volt wires (Allowing twice the potential for voltage 12,000. However, the neutral regulates the two lines to offer only 120 volt power; therefore creating a greater potential to plug into but not overloading your appliances). A surge protector is still recommended for bad wiring and low level surges.
RV’s with 50 amps usually have two lines of 50 (One set of appliance run on one line and another set on the other). When you plug into a campground pedestal you will also see two 50 amp breaker switches (These lines do not run separately but as a whole. Think of them as one switch).
50 amps= 6,000 watts

When plugging in the 3 prong cord...It has a ground, a neutral and ONE 120 volt wire giving exactly what it says 3,600 watts
30 amps= 3,600 watts

Generator

A Generator is the only way of running your appliances without plugging in except to use your Battery. Generators are usually not included in towable RV’s but in the higher end fifth wheels and motorhomes. You can purchase a Generator separately and have it installed. If you do want to use your Battery, you will need an inverter. Also, most towable RV’s do not come with an inverter but some of the higher end motorhomes do.

Some helpful insight...

Nick- Our Service Writer at Valley RV Supercenter.

“All modern RVs that we sell, come with a charger built into the converter. This charger maintains the battery when plugged in and charges the battery when needed. If an RV is plugged in, maintaining water levels is crucial as batteries can boil.”

“Plugging in an RV will charge the house battery but it will not charge the battery under the hood (Motorhomes), so regularly running your engine to maintain the battery is important while storing.”

Valley RV Supercenter