BAC Forum
General Boards => Technical Support => Topic started by: Dave Cunningham on August 02, 2013, 04:29:05 AM
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Hey all,
Just wondering if anybody can help me with this one, I was at an rv park with 30 amp service last week , and when I tried to use one roof top air conditioner, the breaker popped after about 15 minutes, tried it again same thing , had to learn to live without air conditioning for a couple of days , I just figured they had a weak breaker at the site.
Anyway just dropped the motorhome off at a buddy's place and got it all set up for a party he is having this weekend, tried to plug it in to 110 v 15 amp just to keep the batteries up and the fridge on propane, popped that breaker a few times and gave up, went to Home Depot bought all the stuff to wire in a proper 30 amp outlet at their garage , hooked it all up, and same thing , one air conditioner ( tried all three separately ) will only stay on for 10 or 15 minutes.
How could it possibly be drawing enough juice with just one unit running? And shouldn't it be able to run on 15 amps just to charge the batteries?
Any help would be appreciated
Thanks,
Dave
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Dave,
Be sure everything else is off when you make that test. Is the AquaHot breaker off? How many amps are indicated when only the batteries are being charged? Does the 30 amp breaker trip when only the battery charger is on and not the AC?
On the 15 amp circuit, with only the battery charger working, how many amps are being discharged from the batteries?
On the 30 amp circuit, with only the battery charger working, how many amps are being discharged from the batteries?
Your Aladdin screen should be a big part of your diagnosis.
Please get back to us with answers.
Larry
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What does your Alladin say re. total amps being used while the AC is on and when it isn't? When everything you know of is off?
Joel
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Thanks guys, I will check all these things, when I get back to the coach later tomorrow , I never thought about the Auquahot heating element, but just in general should you not be able to run one rooftop air and a few minor things , on 30 amps?
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Dave,
It is simple math. Add all the current draws. If they exceed the breaker limit, the breaker will trip when it gets hot enough. The inverter/charger is about 8 amps. The AquaHot is about 15 amps. The AC is about 13 amps. The refrigerator is about 6 amps. Lights are about 1 amp each. When you exceed the breaker limit, it protects you by tripping. You become an amp manager, and turn off most things to operate one thing you want on. You may want to make a list of how much each appliance draws, to properly manage the electricity available. Watch your Aladdin screen as you turn on or off an appliance, and note the current change. This is a good project to learn the RV life.
Larry
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"50 Amp" hookups are really 100 amps. Anything else is a severe restriction to a Beaver and must be managed.
On mine, if the batteries are low, the charger can use a lot of amps for a short period. It does not know when 100 amp hookups are missing. It will surprise you by tripping a breaker when you think your are managing the loads.
Normal "50 Amp" hookups are a pair of 50 amp breakers. Our tipical motorhome is wired with each breaker feeding a full 50 amps into separate circuit "legs". If you do a 30 amp or 15 amp hookup the motorhome is tricked by the adapter to share that source to both legs. So instead of 100 amp potential, you get only a fraction. Most of us have 7500 watt gensets that have a pair of 30 amp breakers. So, even that puts the motorhome on a 40% off electricity diet.
100 amp hook ups: run everything you want, anytime you want it.
Genset only: almost the same, with one exception. If you've been using your house batteries, the charger may want a significant portion of it's 30 amp source. If you turn something else on, like the A/C on that same "leg" the breaker will pop. The solution is to wait for the charger to catch up a little or find the control to restrict it's draw.
30 amp hook ups: You get two run two things. It could be a hair dryer and the hydrohot. Or, one A/C and a toaster. Your chances of uninterrupted power are improved if you turn off the Hydro-Hot electric element, switch the fridge to propane and limit the charger's draw to 10 amps. You might be able to run two A/C units if you manage it right. Once they are running, they use about 13 amps each. So if you can shed everything else, 30 amps can do it. If you get them both running, keep the temp set extra low so that the compressors don't cycle on and off. It is the compressor start up that momentarily requires a high amp load.
15 amp hook ups: You can run only one thing. If you let the fridge run on electric, you get nothing else. You have to switch the fridge to propane and lower the charger draw to 5 or 10 amps. My favorite way to do this is to NOT plug in the motorhome at all. Instead, I put a standard battery charger on the house battery bank and let the inverter power everything. The big draw electric items can't turn on and you can still run a hair dryer or toaster using inverted power from the batteries. The batteries will slowly recover from the charger.
The genset normally has priority over shore power. So, if you do have only 15 or 30 amp hook ups and need to run something like a hair dryer or margarita blender, start the genset. You have to wait a minute or two for it to warm up and it will assume the load. You don't have to unplug the cord. When the hair is dry or the margarita pitcher is full, turn of the generator and the shore connection will take over.
I've comfortably camped in cold weather as a driveway guest with only a long orange cord to a 15 amp outlet in the garage. The key is to make sure you manage the charger draw.
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On mine, if the batteries are low, the charger can use a lot of amps for a short period. It does not know when 100 amp hookups are missing. It will surprise you by tripping a breaker when you think your are managing the loads.
Both the Xantrex and Magnum inverter/chargers permit you to set the amperage rating of your hookup so this doesn't happen. If my batteries haven't been heavily discharged I don't bother to do it, but if I am connected to a 20A circuit at someone's house I definitely do.
We've been in Canada for a month on 30A hookups without any real issues, but, of course, we haven't needed A/C. Sometimes I turn the electric H/W off and let our Hurricane handle our hot water needs while we are cooking and running multiple appliances.
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Thanks again for your explanations, I do understand how the 50 ( 100 amp) and 30/15 amp supplies work, I just couldn't understand how with everything shut down , a 30 amp supply couldn't run the rooftop and charger, and I think you have answered that question for me, by reminding me that the Auquahot electric element comes on automatically, I will shut it off , check all my draws, and let you know how I make out.
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Thank you Bill for that information. Very helpful in understanding our coach's sources and uses of electricity.
Stan
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Dave,
You may want to consider adding a switch in the AquaHot circuit. You can interrupt the hot AC lead at the junction box on the AquaHot. Run a length of romex wire up through the floor to a switch box added to the wall of the living room. Then it will be convenient to turn on and off the electric element of the AquaHot, when less than 50 amps is available. It also eliminates using the breaker as a switch.
Larry
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Thanks Larry that is a good idea, I returned to our camping spot on Saturday , shut off the Auquahot and everything works now, can't believe I didn't think of it before.
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On our Beaver the Aqua Hot 110 volt heating element is on a seperate breaker and just turn it off at the breaker box instead of another switch. Do not see a reason to add a switch?
We had some friends store a beaver and they had a draw from the engine preheat they had left on and it drew 4 amps.
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Richard,
The reason to add a separate switch for the electric element on the Aqua Hot unit is two fold. First, a switch in the living area is more convenient than using a breaker in the electrical center. Second, the failure rate on a breaker that is used as a switch is high, because it is not designed to be a switch.
If someone leaves the engine preheat switch on, they are just running the electric pump that circulates engine coolant through the Aqua Hot/Hurricane heating system. This serves no purpose unless the heating unit is running.
Gerald