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Campground Power
- By TomW
- Published 10/15/2008
- Trips & Camping
Like many people, our idea of “roughin’ it” in the great outdoors now involves doing so in an air-conditioned Airstream with full hookups. Water & sewer hookups have never been an issue, but electrical power quality can be a problem especially if the weather is warm and the campground is fairly full.
Most appliances will still work okay with poor quality power without damage. The air conditioner’s compressor, however, does not fall in this category. When the campground voltage is low, the compressor will pull more current. More current means more heat localized to the compressor’s internal motor windings. Eventually, the motor will give out. Nowadays, the entire AC unit is typically replaced instead of repaired which can add up to some serious bucks even for the do-it-yourselfer.
What can you do? Check your line voltage. In a properly designed campground, a 30 amp outlet should read 120 Volts Alternating Current (vac) on a voltmeter. Inside your Airstream, without any big appliances running, any given outlet should read about the same. Switch on the AC, though, and you will probably see the voltage drop to around 118 vac. Turn on a hair dryer or water heater, and you may see the voltage drop even more.
Most electrical appliances are designed around a working voltage of 115 vac. So as long as your voltmeter reads between 115 & 120 volts, everything is fine. High voltage (125 vac or greater) is possible but rare. Disconnect if your meter reads 135 vac or higher.
If the voltage reads between 110 & 115 vac, and AC is desired, it is best to run nothing but the AC. While most compressor manufacturers list 105 volts as the absolute minimum, I personally would need a really good reason to operate my air conditioner if the voltage is below 110 vac.
If you are disinclined to lug around a voltmeter, Camping World sells a plug-in device for around $50 which displays line voltage. It even has under & over voltage audible alarms.
Another problem experienced by some campers is a tripped circuit breaker. This usually results from having too many appliances on at the same time. People who remember the television show Green Acres might remember that Mr. Haney sold the Douglas’s a generator with limited output. Lisa & Oliver had to be careful how many appliances were plugged in to the outlet strip or the generator would blow out. They accomplished this by labeling each cord with how many amps a given appliance required, and limiting the total amperage to under the generator’s capability. Of course if they had had a main breaker, the generator would have been protected. But the physical comedy of smoke & noise pouring out of the unit could not have been done.
You too can return to Green Acres with this general guide:
But it is possible to trip a main breaker, even with careful planning, due to start-up surge. Some appliances, like the air conditioner & microwave, require a large amount of power for a split second just to get running. Circuit breakers can normally accommodate this brief flow of extra power. But if a lot of devices are already running, it is hit or miss sometimes as to whether the breaker will hold.
So what do you do if your campsite has poor power quality? If you are using an extension cord on your shore power cord, try to hook up without it. Its use will introduce a voltage drop, and some cheaper extension cords are made with substandard connectors which will make things even worse.
Try a different campsite. Look for one that is close to the campground’s power distribution point. If the campground is fairly full, and everyone is running an air conditioner, the poor power quality might be the result of a poorly designed campground power grid. Your only option might be to go to another
campground.
Some people do not leave home without a Hughes Autoformer. This 24 pound device, which is connected in series with your shore power cord, will boost the line voltage should it go low. I have read nothing but good reports about its operation. At around $400, though, it is not inexpensive. But air conditioners are not either.
Happy camping, and check your voltage!
Most appliances will still work okay with poor quality power without damage. The air conditioner’s compressor, however, does not fall in this category. When the campground voltage is low, the compressor will pull more current. More current means more heat localized to the compressor’s internal motor windings. Eventually, the motor will give out. Nowadays, the entire AC unit is typically replaced instead of repaired which can add up to some serious bucks even for the do-it-yourselfer.
What can you do? Check your line voltage. In a properly designed campground, a 30 amp outlet should read 120 Volts Alternating Current (vac) on a voltmeter. Inside your Airstream, without any big appliances running, any given outlet should read about the same. Switch on the AC, though, and you will probably see the voltage drop to around 118 vac. Turn on a hair dryer or water heater, and you may see the voltage drop even more.Most electrical appliances are designed around a working voltage of 115 vac. So as long as your voltmeter reads between 115 & 120 volts, everything is fine. High voltage (125 vac or greater) is possible but rare. Disconnect if your meter reads 135 vac or higher.
If the voltage reads between 110 & 115 vac, and AC is desired, it is best to run nothing but the AC. While most compressor manufacturers list 105 volts as the absolute minimum, I personally would need a really good reason to operate my air conditioner if the voltage is below 110 vac.
If you are disinclined to lug around a voltmeter, Camping World sells a plug-in device for around $50 which displays line voltage. It even has under & over voltage audible alarms.
Another problem experienced by some campers is a tripped circuit breaker. This usually results from having too many appliances on at the same time. People who remember the television show Green Acres might remember that Mr. Haney sold the Douglas’s a generator with limited output. Lisa & Oliver had to be careful how many appliances were plugged in to the outlet strip or the generator would blow out. They accomplished this by labeling each cord with how many amps a given appliance required, and limiting the total amperage to under the generator’s capability. Of course if they had had a main breaker, the generator would have been protected. But the physical comedy of smoke & noise pouring out of the unit could not have been done.
You too can return to Green Acres with this general guide:
- Power converter 5 – 7 amps
- Air conditioner (15,000 Btu) 12.5 amps
- Electric water heater (6 gal) 12.5 amps
- Microwave oven 12.8 amps
- Electric coffee maker 9.0 amps
- RV refrigerator (on electricity) 2.5 amps
- Toaster 10 amps
- Hair dryer 12.5 amps
- Television 2.0 amps
- Electric skillet 10.0 amps
- Iron 10.0 amps
- Food processor 6.0 amps
- Crock pot 1.5 amps
- Space heater 12.5 amps
- Heating pad 0.5 amps
- Cell phone charger 0.1 amps
But it is possible to trip a main breaker, even with careful planning, due to start-up surge. Some appliances, like the air conditioner & microwave, require a large amount of power for a split second just to get running. Circuit breakers can normally accommodate this brief flow of extra power. But if a lot of devices are already running, it is hit or miss sometimes as to whether the breaker will hold.So what do you do if your campsite has poor power quality? If you are using an extension cord on your shore power cord, try to hook up without it. Its use will introduce a voltage drop, and some cheaper extension cords are made with substandard connectors which will make things even worse.
Try a different campsite. Look for one that is close to the campground’s power distribution point. If the campground is fairly full, and everyone is running an air conditioner, the poor power quality might be the result of a poorly designed campground power grid. Your only option might be to go to another
campground.
Some people do not leave home without a Hughes Autoformer. This 24 pound device, which is connected in series with your shore power cord, will boost the line voltage should it go low. I have read nothing but good reports about its operation. At around $400, though, it is not inexpensive. But air conditioners are not either.
Happy camping, and check your voltage!
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8 Responses to "Campground Power" 
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said this on 22 Oct 2008 5:39:54 PM CDT
We always use a volt meter and polarity checker when settling down at a campsite. Recently we sprung for a 30A former. It has made all the difference in the world when it comes to using necessary electric appliances. Yet it still maintains the equation of (1V x 1A = 1W). And yes, the Lisa Douglas analogy really works.
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said this on 05 Jan 2009 2:11:59 PM CDT
One other important issue that needs to be checked and is almost as important as the low voltage issue. That is the frequency of the AC coming into the trailer. Here we have found that some who use gen sets are not aware that if the frequency (60 cycles) is low... even though the voltage is 120 volts... you will not get the power your requireing. You can actually burn out the compressor and other items because it then cause a higher than normal current draw.
Compressors are frequency dependent to make them run at the rated RPM. If the frequency of the power coming in is low it can hurt them. If high it can damge them also. Thus you want to add a frequency meter to the old inst pannel in the trailer... so that you can see the voltage, frequency and current demands your placing on the line. Auto adjusting transformers are good for pumping up the voltage when low. But won't work if they are off AC frequency (60 cycles) which they were designed for. For more info on transformers and how they work check out google for ac transformers and frequency dependency. If you run off of a gen set... you need to have a calibrated frequency meter to insure that the 60 cycles is right on. ( a cheap way to do it also is to use a AC powered clock that has a motor in it. Here you use your watch or stopwatch and time it for 1 min. If both hands of the two clocks are on the same number when done.. your pretty close to 60 cyc... but todays clocks mostly have been changed to digital and only convert the power to DC to run them... so make sure its a old motor one. ) If you need better meter... radio shack. |
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said this on 05 Jan 2009 3:44:44 PM CDT
"... if the frequency (60 cycles) is low... even though the voltage is 120 volts... you will not get the power your requireing. ..."
To be quite honest, I can not see how the above scenario would ever happen with the generators commonly associated with gen sets. And power is a function of current & voltage only. On most gen sets, frequency is determined by the speed at which the generator's armature is rotating (usually 1800 or 3600 rpm). A little slow, and frequency drops. The voltage will drop too. A little fast, and the opposite occurs. I did not mention frequency in my original article because the slant was toward people who plug into campground power. While it is great to be able to monitor frequency, I feel that the general camping populace will do just fine by just monitoring voltage. If the frequency is off, line voltage will be affected. TomW |
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said this on 08 Jan 2009 3:00:53 AM CDT
I agree with you Tom... on the shore power... but some places have gen sets that provide power till a hour and then go quiet. such as in mexico.
As to the voltage going low. Most alternators have voltage regulators built into them. Even if the RPM drops the voltage regulator will throttle the alternator so that it keep the voltage up around 120. As you know the motor on the AC is like a transformer and frequency dependent on getting up to RPM. If the frequency is down it won't be making the RPM or putting out the required power the compressor side would need to perform correctly. Most of the AS people now use some sort of AC gen set to power the trailer while sitting when they are away from the shore power or out in the rough. it is actually more common than it used to be as most enjoy the AC and other good life electric dependent items now a days... No the article was very informative and hope you will keep writing more... GMAs |
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said this on 31 Jan 2009 7:34:16 PM CDT
It sounds to me that you have this figured out! I am just in the process of shopping for my RV. If I am not in a campground that supplies power (more wilderness sites) can I plug in my laptop to an outlet in the trailer and have my laptop run off the trailer batteries? Would I have to run a generator and what size generator? Multiple electrical appliances would not be an issue but I would like to do some writing on my laptop while off in the wilds.
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said this on 09 Feb 2009 2:59:13 PM CDT
The laptop will probably require more power than the batteries provide if you use the power brick that plugs into you household electrical socket. However, you may be able to find a car/airline adaptor for your laptop that will run it from a 12volt source, if so, you can plug it in and you are in business!
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said this on 24 Feb 2009 12:00:15 AM CDT
If I were going to use a 25 ft. Air Stream in a trade show using Refregerator, AC, TV computers etc. How many AMPs would I tell them I needed?
Thanks for the help. Kathryb |
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said this on 23 Jun 2009 1:36:25 AM CDT
Kathryb,
You would need a thirty amp, 240 volt circuit. You can run the AC using 20amp 120 volt circuit but just the AC will pull 12.5 amps, not leaving much for the Fridge, TV, Computers, and lights etc. |
