120-Volt Energy Management: Part 2

Earlier, in Part 1 of this series, we discussed an overview of the 120-volt AC system and how electricity comes in from the shoreline source and supplies the appliances. In this article we will talk about what individual appliances require for electrical power, and how to manage your system to prevent overloading the source.

Most campground sources or shoreline power will have two or three outlets available for power. Smaller campgrounds typically only have 15-amp and 30-amp power which will limit the number of appliances you can run, and are usually not a good option for the bigger 5th wheel trailers or large motorhomes. To run both roof air conditioners and other appliances, these rigs require 50-amp power which supplies two “legs” of 120-volt power.

Proper energy management starts with an understanding of what power your appliances will draw in your rig. Most 120-volt appliances will have a data plate that has the model, serial number, and amp draw at maximum capacity. Maximum capacity means the amp draw when that appliance is working at the highest load. For example, an air conditioner that might only draw 8-10 amps during fairly cool temperatures but will draw a maximum of 14 amps when it is really hot.

Make a list of all the appliances in your coach that operate on 120-volt power and use the chart below to see what applies to your rig:

Notice there is quite a range in the amp draw for some of the appliances, such as a microwave that can be anywhere from 6-13 amp. It’s important to identify your specific model and calculate the draw. However, there is an easier way which we will cover later.

Let’s look at a typical RV plugged into a 30-amp shoreline plug. The power comes into the distribution center with a main circuit breaker and has individual breakers for appliances such as the refrigerator, air conditioners, and others. If you are running one air conditioner it could draw 8 amps at moderate temperatures and up to 14 amps during high load. Units built before 1990 might have air conditioners that could draw up to 18 amps!

Let’s say your refrigerator running on 120-volt power is drawing 6 amps, so in theory this rig is only drawing 14-20 amps during normal operation. But now we need to factor in the temporary usage appliances and the battery converter or charger! Interior lights, roof vent fans, LP appliances and other system running on 12-volt power draw from the house batteries and the converter or battery charger will kick on to recharge the batteries as they draw down to a certain voltage. This can draw anywhere from 4-9 amps without any warning! Most RVers understand that using a microwave oven, toaster, or other 120-volt appliances will create a spike in the amp draw and plan for it. However, you need to be aware of these items that will create a “peak” in amp draw such as the converter.

Now it is time to find the actual amp draw of your appliances. Keep in mind, anything that creates heat with a glowing coil or metal such as hair dryers, curling irons, or hot plates draw a lot of amps. You need to know what that appliance draws so when you use it temporarily, you might need to shut something else off, like the roof air conditioner. I use a meter called Kill A Watt which plugs into any 120-volt outlet and then plug the appliance in to find the amps or watts it draws. You can find these on Amazon or at any home improvement store in the electrical department.

Plug in all appliances that will be used even temporarily to calculate the amp draw. Don’t forget about the chargers for cell phones, laptops, and CPAP machines at night! Once you get all the data collected, you will need to physically manage the energy draw by shutting off items like the roof air conditioners, refrigerator, or electric water heater while temporary appliances are being used.

There is another option though, an energy management system (EMS) such as the Intellitec model which is used by several manufactures in larger units. This system has appliances such as the roof air units, refrigerator, and electronic water heater connected to a smart computer that will automatically shut off these appliances temporarily as the amp draw gets over the limit. In the case of the air conditioner, it shuts down the compressor, but the fan will still run to provide air flow, then the compressor if needed. For the refrigerator, it will shut down the 120-volt operation which means it switches over to propane. All this is usually is for about 2-3 minutes as the microwave or other appliance is drawing a higher load so food will not spoil and the interior temperature will not get uncomfortable.

Here is an example of the Winnebago version called Powerline which tells you the AC amp load and sheds appliances.

An easier option is the Surge Protector by Surge Guard which is a protection from a spike in voltage from the campground source and will shut down if the power from the source goes down below 110-volts. This protects motors and condensers in appliances but also shows the amps your rig is using at a quick glance. You can get this portable version, or a more secure option can be permanently mounted in your service compartment.

Whatever method you use, it’s important to understand the load your appliances and equipment will draw and manage it according to the power available.

To read more about 120-Volt Electrical Systems, check out Part 1: 120-Volt Electrical Basics!

Discussion
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20 Responses to “120-Volt Energy Management: Part 2”
  1. Danny Carver

    RV Make: 1999, RV Model: American Eagle, RV Year: 1999

    Where do I find the Converter on this RV?

    Reply
    • Customer Service

      Hello Danny,

      What is the year, make, and model of your RV?

      Thanks
      Becky RVRC Video Membership

      Reply
  2. john

    RV Make: fleetwood, RV Model: bounder, RV Year: 2005

    location of converter 2005 fleetwood bounder ?

    Reply
    • Customer Service

      Hello John,

      The location of the converter depends on the power option that was spec’d for that model and if it has an inverter/charger. Typically the 30 amp models had the converter incorporated with the distribution center, however larger models had a stand alone converter that was often times hid underneath the refrigerator or other cabinet in the kitchen area. Some were even put in the basement as they were noisy and got hot. You should be able to hear the fan running when plugged into shoreline power.

      Thanks,
      David RVRC Video Membership

      Reply
  3. Richard

    RV Make: Thor, RV Model: Hurricane, RV Year: 2016, Brand: xantrex inverter, Model Number: 1800

    I have no power to my inverter control panel or to my inverter – have power when plugged into shoreline, and it appears that inverter is working, but control does not light up. Could it be just a bad panel?

    Reply
    • Customer Service

      Hello Richard,

      To provide more specific troubleshooting information regarding your inverter, we need the make and model of the inverter. If you have power to all 120-volt functions when connected to shoreline power, do you have all the 12-volt functions as well such as lights, vent fans etc and all the 12-volt functions work when unplugged? If you have verified 12-volts and 120-volts coming out of the inverter since you indicated it is working, then it seems to be the control panel?

      Thanks,
      David RVRC Video Membership

      Reply
  4. david

    RV Make: winnabago, RV Model: minnie, RV Year: 2001

    do the back up batteries in the unit need to be unhooked in winter.irun the vehicle and generator for half an hour once a month.

    Reply
    • Customer Service

      Hello David,

      If you have lead acid batteries, they need to have a multistage charge once a month which is a high voltage “bulk” charge (16-volts) that literally boils the acid and breaks up the sulfation and then goes into a bulk and equalizing stage charge. Running the generator once a month during storage is good, however if you do not have a large inverter/charger with the multistage charge, or a converter such as the Progressive Dynamics converters with Charge Wizard. Find out more info here: https://www.progressivedyn.com/rv/charge-wizard/

      You can also install a Battery Minder available at Northern Tool which will condition batteries and break up sulfation.

      Thanks,
      David
      RV Repair Club Video Membership

      We’d love to have you be a part of our community. We are convinced you will enjoy the benefits of becoming a member and having access to the best instructional how to videos and professional tips. We would like to offer you a special promotion for your first year membership.
      https://go.rvrepairclub.com/C11475

      Reply
  5. Gerald

    RV Make: Fleetwood, RV Model: Wolderness, RV Year: 1982

    Looking for repair and Maintenance manuals

    Reply
  6. Jack

    RV Make: Winnebago, RV Model: Minnie 24V, RV Year: 2005

    My control panel lights are always on when main disconnect is on. When unit was new ,you would have to push the switch to see all the tank levels,battery charge & lp level. Everything works fine but the light panel is always on. Is this common or will I have a problem down the line.

    Reply
    • Customer Service

      Hello Jack,

      This is not normal, and since it did not work this way when new, somewhere you got a short in the monitor panel. Since the levels read correct, it’s probably in the switch itself staying in the closed or “connected” position. I would remove the switch and clean all the terminals or replace the switch as eventually it will burn out the lights and may create enough heat to melt some plastic component and cause more damage later?

      Thanks,
      David RV Repair Club Video Membership

      Reply
  7. anoziranats

    RV Make: Forest river, RV Model: Rcockwood, RV Year: 2007

    How does the inverter work

    Reply
    • Customer Service

      Hello,

      An inverter takes 12-volt DC power from the house batteries and inverts it to 120-volt AC power for outlets and other appliances. Smaller inverters are used in the entertainments center to just power the outlet to the TV and DVD player. Larger inverters can power more outlets and appliance with some even running residential refrigerators on 120-volt power. However the more you power, the more battery capacity you need. These larger inverters also act as converters or chargers for the house battery bank as they have multistage charging for better conditioning and less sulfation.

      Thanks,

      David
      RV Repair Club Video Membership

      Reply
  8. Susan

    RV Make: Sun Valley, RV Model: Bridgeport, RV Year: 2009, Brand: Suburban, Model Number: IW60

    I need help understanding how to connect the wiring in my travel trailer to my new on-demand tankless water heater. It is replacing my suburban 6 gallon water heater.

    Reply
    • Customer Service

      Hello Susan,

      To provide more specific information on connecting your on-demand system we need the make, model, and year of your on-demand system. There are several on the market such as Truma, Girard, and Atwood.

      Thanks,

      David
      RV Repair Club Video Membership

      Reply
  9. Edward Bush

    RV Make: county coach, RV Model: LTD, RV Year: 1987, Brand: coleman AC, Model Number: Delta T

    AC has low power light and will not blow cold air.

    Reply
  10. jarnaginagency

    RV Make: DRV, RV Model: Mobile Suite 38-RSSB3, RV Year: 2016

    I can not for the life of me locate my inverter, and there is no owners manual showing the location, I have looked in, and around the battery compartment but no inverter there just a bunch of auto leveling parts and pieces I see pictures of what it looks like but can not locate it?? Thanks Jim

    Reply
    • Customer Service

      Hello,

      If you have a fifth wheel, I have seen them mounted on the ceiling of the large storage compartment in the front. It will have very thick wires running to the battery, the best thing to do it try to trace the wires. The inverter is usually located outside of the main living area but it could be installed by the distribution center. Since there are buttons and fuses attached to the inverter, they are typically not confined to a hidden area.

      Hope this helps,

      Dan
      RV Repair Club Video Membership

      Reply
  11. Matt Caldwell

    RV Make: Country Coach, RV Model: Magna Monet, RV Year: 2005

    This RV is an “all electric” model, as there is no propane onboard. Hydronic heating. I think it has two Inverters to each run individual groups of circuits. I also believe that each of these Inverters are supported by their own battery bank. If I turn off one of the Inverters while not connected to shore power, will that show me what circuits that inverter runs? (due to lack of power)?
    Also, my distribution panel has 4 – 30 amp breakers marked Inverter #1 or #2. Any idea why it would have 4? The Inverters are Xantrex ProSine 3.0. Thank you.

    Reply
    • Customer Service

      Hello Matt,

      Yes, if you turn off one of the inverters while disconnected to shore power you will be able to find out what is on that particular one. You can use a circuit tester to help identify what outlets are on that circuit as well. Do you have a 50 amp shore cord? If you have a 50 amp, there will be 2 hot legs coming in and they may have split them into 2-30 amp legs. With this, you can have 30 amps on one leg and 30 amps on the other. If your shore power is only 30 amps, the whole system will share 30 amp total. Usually there is one breaker dedicated to the leg itself the other breakers to the circuits. You may have 2-30 amp legs and then a 30 amp breaker to each of the inverters for a total of 4. The inverters do have to be on their own breaker and are required to be 30 amps.

      I hope this was helpful!

      Dan
      RV Repair Club Video Membership

      Reply