RV power consumption plugged in and on propane

[Rowatt]

I’m trying to figure out where a power draw is going -looks like an additional 20 KWh per day after an RV has been connected to our house but the guest says there is no way it’s that much because they are on propane. I have zero knowledge so I’m trying to find information for everyone, and also interested in getting an RV for myself and trying to learn how much $$$ these take to run.
I apologize if this isn’t in the right section, I’m brand new here and this is my first post.
Thank-you in advance

 

[Mark_K5LXP]

20kWh is a heater or air conditioner. Nothing else in an RV even comes close.

Mark B.
Albuquerque, NM

 

[OldWEB]

20kWhr in a day equates to:
a 5kW heater running for 4 hours... or
20,000Whr ÷ 24hrs = 833W an hour
833W ÷ 120V = almost 7 amps every hour for the day. (or 14 amps for half the day)

I hope my math is right.... ;-)

Unbeknownst to them, maybe they have the electric element in the water heater on, that is something like a 10 amp draw I believe.

 

[OldWEB]

And remember, if the guest is a friend, do not lose that friendship over what may be $2/day (20x$0.10kWhr).... unless this is a long term thing.

 

[Kirk]

Watts are equal to the amps of current multiplied by the voltage. Watt hours is the amps times volts, times hours. So 1A at 120V is 120 watts and if used for 1 hour that is equal to .12 kilowatt hours. Most RVs use propane for heat but the furnace blower is 12V-dc current and that would be supplied by a converter that changes 120V-ac from shore power and makes 12V-dc to supply all of those loads. It is possible to operate most RV refrigerators on propane if they have an absorption refrigerator and if they set it to do so, as most of them operate in automatic most of the time and thus shift to 120V when available. They also may have a 120V heating element in their water heater or it might operate on propane, again an operator selection.

The 20 KWH per day is spread over a 24 hour day and if the loads were all uniform all day long, that would only mean it was using 6.95a constantly or the equivalent of that. That is probably a bit high, but not outrageous. If you figured 10 kwh per day that would be an average of only 3.47a spread over 24 hours. It is very difficult to estimate what the load is over 24 hours since it probably varies a lot. A factor that should be considered is what sort of outlet he is plugged into. If it is a typical house, 15a outlet then it would be difficult for them to consume 20 kwh per day but easy to reach 10 kwh.

 

[Mark_K5LXP]

A water heater shuts off after a while and stays off unless they use a lot of hot water all day, so while the peak draw is there, the duty cycle is not. Something like a residential fridge is considered a power hog in RV terms but that's usually referenced to drawing from batteries, not AC mains. 1.2kWh per day would be my estimate for a refrigerator. 20kWh a day is roughly what my S&B home draws running 2 refrigerators, TV's, lights, appliances, furnace, everything. For an RV to be drawing what an entire home might implies a persistent moderate load. Being winter time and RV insulation what it is, my money's on an electric heater. Maybe it's one in a basement compartment to keep pipes from freezing, or other unseen purpose. With this number of watts being drawn it's pretty hard to hide. Something's getting warm or getting moved.

Mark B.
Albuquerque, NM

 

[Rowatt]

And remember, if the guest is a friend, do not lose that friendship over what may be $2/day (20x$0.10kWhr).... unless this is a long term thing.

She’s our landlord and she wants us to pay for most of it because she doesn’t think she’s using that much. It went up 15-20 kWh the day she got back after a month when we established a solid average. Maybe it’s the water heater ? I thought I’d come and ask the experts -

 

[Utclmjmpr]

She may be on propane,, but the pumps and blowers that also are used in conjunction with the propane use, adds up..>>>Dan ( Using her analogy, she doesn't need to be plugged in at all.)

 

[Rowatt]

Watts are equal to the amps of current multiplied by the voltage. Watt hours is the amps times volts, times hours. So 1A at 120V is 120 watts and if used for 1 hour that is equal to .12 kilowatt hours. Most RVs use propane for heat but the furnace blower is 12V-dc current and that would be supplied by a converter that changes 120V-ac from shore power and makes 12V-dc to supply all of those loads. It is possible to operate most RV refrigerators on propane if they have an absorption refrigerator and if they set it to do so, as most of them operate in automatic most of the time and thus shift to 120V when available. They also may have a 120V heating element in their water heater or it might operate on propane, again an operator selection.

The 20 KWH per day is spread over a 24 hour day and if the loads were all uniform all day long, that would only mean it was using 6.95a constantly or the equivalent of that. That is probably a bit high, but not outrageous. If you figured 10 kwh per day that would be an average of only 3.47a spread over 24 hours. It is very difficult to estimate what the load is over 24 hours since it probably varies a lot. A factor that should be considered is what sort of outlet he is plugged into. If it is a typical house, 15a outlet then it would be difficult for them to consume 20 kwh per day but easy to reach 10 kwh.

Wow ! Thank-you for this information-I’m starting to get a grasp at how it works thanks to you. It’s actually my landlord -she was gone when we moved in and we had a whole month and the day she got back it went up between 15-20 kWh per day, but she got offended when we showed her the data thinking we were accusing her of lying about not using a heater. It’s really a touchy and uncomfortable situation, but at the end of the day when we look at the data and know we haven’t changed anything on our end and we are stuck with the bill it needs to be figured out … ugh I’m just trying to figure out what it could be so I can approach this truthfully fairly and diplomatically.

 

[OldWEB]

In Canada? Here is a Kilowatt meter for the typical 15A plugin.

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www.amazon.ca

 

[Rowatt]

She may be on propane,, but the pumps and blowers that also are used in conjunction with the propane use, adds up..>>>Dan ( Using her analogy, she doesn't need to be plugged in at all.)

That’s what I thought was wrong with her analogy -my bet after reading your and all other comments here is on the water pump/heater… it’s our landlord actually -she wasn’t here when we moved in and so for a whole month we were able to establish an average and on the day and every other day since she’s been plugged in our consumption has gone up between 15-20 kWh per day, but she only wants to pay less than a third of that. It’s an uncomfortable situation.

 

[Rowatt]

In Canada? Here is a Kilowatt meter for the typical 15A plugin.

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www.amazon.ca

Thank-you! This is awesome!

 

[Rowatt]

Thank-you! This is awesome!

This will save the situation- it has been a super touchy one -

 

[Mark_K5LXP]

Another way to look at it is RV appliances and accessories run at a fairly nominal power level, as RV's are intended to run off of a fairly limited supply of battery power. 20kWh current draws would kill most RV batteries in maybe an hour or two. So it's not going to be any of the typical house loads. Even if all the battery accessories are on at once you can't hit 20kWh a day, the charger doesn't have that capacity and it would be awfully bright and noisy inside with everything turned on and running. There just aren't that many things in an RV that run solely on shore power, namely the A/C, water heater if it has an element, and any resistive heaters. 20kWh a day equates to over 800 watts average, which is not an insignificant power to be used. A water heater element can draw more than that but even at 1500 watts, that's about 12 hours of cumulative water heater operation per day - that's a lot of hot water. A small ceramic space heater, perhaps a "decorative" faux fireplace, or a heater in a cold basement compartment can easily draw this kind of power over the span of many hours.

A simple Kill A Watt or clamp on amp meter on the shore plug and flipping a few breakers will reveal where the load is. It can also demonstrate the actual power being drawn at any given moment, eliminating having to guesstimate via monthly residential billing.

Mark B.
Albuquerque, NM

 

[Rowatt]

In Canada? Here is a Kilowatt meter for the typical 15A plugin.

Loading…

www.amazon.ca

I just ordered one

 

[OldWEB]

Well with her being the landlord, yes it can be delicate. But she still has no right to just "steal" your power and she decides how much to pay. This should settle it and to test it, look at the nameplate of a kettle or toaster for the watts usage and plug that in first... should be accurate enough.
Good luck

EDIT: Be careful with the two terms, kW and kWhr, the first is instantaneous power being used and the -hr suffix refers to a period of time for the power consumed.

 

[Rowatt]

Thank-you - It’s one of those situations that I feel like I shouldn’t even have to deal with but here we are !

 

[Hvactech]

This will save the situation- it has been a super touchy one -

Do you have a lease that states your landlord gets to freeload electricity & water ? Just unplug her. She'll then tell you what' she has hooked up.

 

[Kirk]

Even if all the battery accessories are on at once you can't hit 20kWh a day, the charger doesn't have that capacity

A typical 120V/12V converter found in most RVs will have a 45a output which if run 24 hours would take up about 13 kwh by it's self. If the RV happens to be one of the larger ones or perhaps a diesel class A then it probably at least a 65a or 18.7 kwh and there are a few that have a 90a converter that can supply 26 kwh if run all 24 hours. (uncommon but possible.) While few RVs ever draw anything like the maximum for hour after hour, it is fairly common for the total of the 12V loads to use more than the maximum output of the converter for a fairly short time by drawing from the batteries, with the converter then recharging the batteries after the load goes back down by staying at max until the batteries have been recharged. Without knowing a lot more about the RV in question any maximum power that it could use is no more than a guess. Getting one of the watt meters that record the cumulative Kwh is the only way to know what they actually use, assuming that they are plugged into a typical, 3 prong, 15a outlet. If you have one of the 30A outlets then you will need a 30a watt meter to do the job and it will cost much more.

 

[TheBar]

She may be thinking because her RV is smaller than your house it takes way less to heat it, when it fact it takes much more because RVs have poor insulation.

I have to ask, was the ambient temperature the same every day and every night after she moved in? I would never be able to establish a accurate daily power draw at my place because the daily temperature varies so much.

Without separate electric meters is it possible your own power usage changed along with hers? Did the other person living with you do something different? Like bumping up the thermostat after you went to work or to bed? Or start baking cookies every day?