RV appliances require more power to START UP than they require to run after starting. For example a 15,000 BTU AC can draw 14 to 16 amps to start and once the compressor engages it may only require 12 to 13 amps to run. So the first problem is two AC's could potentially require 32 amps from a 30 amp system. If you have anything else on at the time, like the refrigerator, coffee pot etc. you may only have 20 or 25 amps available.
For two roof AC's to run and be able to use other appliances usually requires a 50 amp system. On 30 amp systems some manufacturers use energy management systems that will start one AC first and once it is up and running the second one will start. Then if you turn on another appliance and the system senses that there is an overload it automatically sheds one of the AC's until there is enough power available for it to start again.
If you attempt to run them both at the same time on shore power you would be using about 26 amps and depending on how many 12 volt devices you were using the converter itself could be using the remaining 4 amps which results in you not being able to use anything else in the RV. Another concern is if the campground voltage drops at all it can create additional problems. Usually if there is not enough power, damage to an AC unit will occur during initial start up.
A better solution for your RV would be to use a 13,500 BTU unit in the front and a much smaller unit like an 8,300 BTU in the rear of the RV. Some of the new AC units require much less energy to run. An 8,300 BTU unit only uses 8 amps versus 13 or 14. This would allow 21,800 BTUs to cool the RV rather than one 15,000 BTU AC trying to cool the RV.
Properly managing the amps being used in your RV can extend the life of your electrical system and appliances.
Copyright 2007 by Mark J. Polk, owner of RV Education 101
RV Expert Mark Polk, seen on TV, is the producer & host of America's most highly regarded series of DVD's, videos, books, and e-books. http://www.rveducation101.com/
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