Funky EMS Issues

ForestRiverTeach wrote:

msturtz wrote:

ForestRiverTeach wrote:
When we purchased our new Thor A.C.E. we had a Progressive Industries EMS unit installed. We'd had a portable one with our last rig, and firmly believe in their ability to save rigs needless damage by shutting them down when the power coming into the rig isn't sufficient to run things, and acting as a sacrificial lamb when there's a power spike. But our current issue has got us scratching our heads.

We're camped at a KOA that is not full. It's not hot. We're not running our AC. But we are running our fridge and hot water tank on shore power instead of propane. When we plug in our coffee pot the EMS shuts down everything else that is running on shore power, and the reading on our EMS shows that we've had a low power event.

Talking with the KOA guys isn't really helpful. They admit that they have no clue about anything electrical. And Progressive has said that their unit is doing what it's supposed to.

Our rig is wired for 30amp. Does that play into this at all? Is it simply an issue of not enough power coming into the rig when we're using the items I've listed above? I don't like having to use propane if it's something that we can address with the rig, but will live with it if it's a campground issue (which I can't do anything about).

I hope I've explained this sufficiently. Thanks for your feedback.

You can figure out this fairly quickly with a little math:
Coffee pot = 10 - 15 amps
Electric hot water heater = 10 - 15 amps
Electric refrigerator heating element = 10 - 15 amps
miscellaneous other loads = unknown but likely another 5 amps
Total draw = 35 AMPs

Note most breakers won't trip immediately for slight overloads. The likely thing that is happening is you are getting a voltage sag which actually increases the current draw of resistive appliances such as coffee makers, heaters and such. I have stayed at KOA camps where the wiring was undersized and the voltage was already low to begin with. I had an Autoformer to boost the voltage to alleviate this particular problem. The formula to figure out how much current you are drawing is quite easy: P=IE or put another more useful way watts = amps x volts. You can use a bit of algebra to figure out how to find the amp draw or wattage if given the other numbers. Note that the lower the voltage is the higher the amperage required to perform the same amount of work or wattage. This means an autoformer is very useful because it will boost the voltage. So if you have a park that only is supplying 109 volts at the pedestal it will boost the voltage to 119 volts allowing your appliances to do the work while drawing less current. Better yet they don't get damaged by a low voltage. This setup complements your EMS system in protecting your rig. If you want to get the actual current draw of each of your appliances there are inexpensive watt hour meters that you can plug the appliance into and then watch the meter to see the actual watts and current drawn by the appliance at a given time. That way you know exactly what can or cannot be used at the same time.

Thanks for your post! I'm going to have to re-read it several times to understand it. ;)

But for now, where does one find an autoformer, and how much do they cost?

An autoformer for a 30 AMP rig costs are as follows:
Amazon:
Hughes autoformer model # RV2130 $388.88
Surge Guard model #10176 $382.72

Camping World:
Hughes autoformer model # RV2130$369.99
Surge Guard model #10176 $410.45

You may be able to find less expensive prices online as well. I have owned both.