Electrical System Mystery - 2006 Monaco Knight

[TeachMePE]

I’m getting things ready to take a trip across the country so I have my RV plugged in at home to 30A. As I am loading up the coach, I went ahead and threw the AC on as it was starting to get hot outside. Both AC’s were running and it was cooling down the rv just fine. Then after about an hour I guess the front AC went off and just the back one was running. I was sure that the set temp was not reached yet so I’m not sure why it went off. It sounded like it was trying to kick back on, but it just couldn’t. I just assumed that because I wasn’t plugged into 50A that might be the reason? So I just shut it off. I tried using a portable AC unit I had in my house inside the rv instead. It was working just fine but after about an hour it just shut off (it was plugged into the rv outlet inside). The outlets were shutting off and resetting, I assume because of the load? After removing the portable AC I plugged in a box fan to get some air circulation. However as soon as I plugged in a vacuum, the outlets shut off and reset. I unplugged from my house and put on the generator. When turning on the AC, only the front one would come on. Thinking maybe the transfer switch? Or the EMS? Anyone experienced this before?

[jacwjames]

Sounds like the EMS is shedding power.  You should be able to see the amp draw on the load meter display to confirm.

[johncvandoren@gmail.com]

On my 2006 Knight I don’t think I can run both rooftop ACs on 30A shore power without tripping the pedestal’s breaker. Six years ago I upgraded them from 13.5K BTU (front) and 11K BTU (rear) to 15K and 13.5K.   Do you have the owner’s manual?  That could shed some light on what you should expect from your system.  My 8KW generator has a 35A breaker, so think it serves only one leg of the coach, so only one AC—not too sure.  When not on 50A shore power or generator, the EMS panel allows me to select incoming power at either 30A (default) or 20A.  Be sure 20A was not inadvertently selected.  The OEM Magnum inverter ME2012 had 2 or 3 resettable pin breakers, one of which would often trip whenever DW tried to run more than one heating device at a time, or turn on the microwave with the AC running while on 30A shore power.   That would knock out the rear bath GFCI and whatever outlets were downstream from there, including the bedroom, front bath and possibly the microwave.  Having installed a residential refrigerator, I went with 400AH of Battle Born Lithium batteries and a Victron MultiPlus II 12/300050 2X120 inverter charger.  Even with all that, we must take care not to put too many heating elements on one leg of the coach.  Good luck, and keep us posted.

[Ivan K]

That's what 'easy start' type of box is for. Not to save electricity or the compressor but to allow it to start with less inrush current. I run 2 units on 30A regularly as long as it is a true 30A circuit. Or 1 unit on 20A.

[jacwjames]

My AC's are new in 2021, and I installed the MicroAir thermostat which sends alerts and the temps can be checked remotely via wifi.

My wife is parked at a friends house plugged into to a 30 amp plug, and she used a 50 amp cord with a 30 amp dog bone so she's getting good power.  She is able to run both AC's if temps get to high.

Fortunately she can usually get by with one and the alerts and my ability to monitor the temps on a regular basis we can make sure the dogs are kept cool.

[Tom Cherry]

Most likely load shedding issues and wear.  When AC’S are new, the starting current will spike up, say 3 -5 amps.  They get older…requires more start up amps.  The soft starts compensate and you don’t get the higher…say 6 - 9 (relatively speaking) additional, over running, amp spikes.

NOW…FWIW.  soft starts have extended the useful life of the air conditioner by keeping the start up amps low enough NOT to blow trip the MAIN 20 amp circuit breaker in the main panel.  But eventually they can not control or phase in the starting current for an old or worn compressor. ALSO, they do nothing to prevent any physical wear or such.  So, they are designed for strictly salvaging older units.

Now, if your KNIGHT is equipped with the Intellitec EMS (look in your manual) then when your demand or Amperage goes above 30 Amps, then the EMS will start yo load shed.  That can get tricky.  There is a “Load Shed” Priority list on the EMS.  What you need to know.  30 Amps is NOT MUCH power.  If your batteries needed charging, then that could have happened….and that takes away Current or Capacity.  

Many, with newer AC’s and understanding HOW to shed power as in converting their halgen puck lights (overhead small ones) to LED can run 2 AC’s on 30 A.  But, you also have to understand that the Refrigerator, assuming you have a GAS unit MUST be on Propane. The electric heaters will pull about 4 Amps.

Now, you brought in a portable cooler.  OPPS…that is fed THROUGH your inverter….assuming you have a Charger Inverter…and not just a “converter” that takes DC and converts it to AC. If you have a combo Inverter/Charger (look in your manual and read about it, it only has a 30 Amp breaker.  The internal outlets are NOT red from a breaker on the main panel. Your internal outlets and microwave come through an Automatic Transfer Switch in the Inverter.  Thus, that limits the power as the charger/inverter is maintaining the batteries…which power your overhead lights and pump and ceiling fan.  Run any of these….bingo, you are overloaded.

That’s how it works….it is all explained in your manual.  The redundancy or duplicity of all the systems in your MH are way more complex and integrated compared to a home residential system is what confuses folks a lot of the time.

Just don’t assume you can plug in the world off a 30 amp pigtail. NOW….BTW, your generator can also be overloaded.  Without looking up the model or specs to see if you have a 7.5 or an 8 or wahtever….it does NOT supply 50 Amp current.  It probably has 2 circuits…but they are only 30 or 35 Amps…so, they may be only 60% of so of a 50A pedestal.  In reality….you have TWO lines of 50 Amp power….or a total of 100 Amps.  So with a single 30 Amp adapter….it is only ONE LINE or 30 amps total….  That’s probably what happened.  Now with your generator, if the breake is a 30 Amp…it only has two (2) circuits   Or a total of 60 amps….again, only 60% of shat you have on 50A service.

 

[TeachMePE]

Thank you Tom for the detailed information! I did read through the manual but it doesn’t go into detail like you explained. I’m glad to know that things are pretty “normal”. Thanks again!