Topic: Low Voltage at EMS (Read 1390 times) previous topic - next topic

Hi all, I am a newbie to the RV life and am trying to get up to speed on how everything works in my 2022 Unity RL which I recently purchased used.  When I brought it home to try out the features I plugged in the 30A shore cord with 115v/15-20A adapter just to run the A/C (nothing else that I knew of was on) but the Electrical Management System kicked off the shore power with a Low Voltage error message.  I checked out the voltage at my receptacle and the voltage on the female end of the shore power cord while plugged in but was all at 120V.  I did notice that with no load on the coach the voltage displaying on the EMS would show 111V but then go down to 104 to 106V when the Xantrex Inverter/Charger would start charging the batteries.  This would cycle between 111V and 104/106V when the charger kicked on and off.  When in charging mode, the EMS also shows a 10A draw which I assume is coming from the charger.  Since I do have the 400W solar panels which also charge the batteries is it wrong to want to bypass the Xantrex unit (while I am plugged in) to get rid of the 10A load and potentially the voltage drop?

The circuit breaker on the receptacle never trips since the EMS stops the shore power on the low voltage error. 
Not quite sure what to do at this point.  I realize I can't run everything while only plugged into a 15A circuit but would like to run one thing such as the frig or A/C.  Am I looking at this incorrectly?

By the way, everything runs fine when it was plugged into a 30A plug at the dealer or when its on the generator.

Any advice is appreciated.

The EMS is programmed to shut down at 108 volts, when you start damaging your electronics & motors.  The refer alone should run on 15 amp circuit, maybe the AC would start with a Soft Start, but still needs full voltage to continue.  What else is on the 15 amp circuit in the house?

As far as I know there was nothing active on the 15 amp breaker.  I have a 20 amp plug that I am going to try and see what happens.  I am also going to call the EMS and Xantrex people to get their opinion.  Perhaps I just need a better understanding of how a RV electrical system works and its limitations.
Harrysalit, Thanks for the reply 

Get a soft start on your AC for sure and it will run on a 15A circuit all day long. We are at a resort and I am plugged into 110 right now with AC full blast. No issues ever. Just make sure to run your fridge on propane when on 15A and not electric or you will trip AC often.

Thanks for the suggestion however due to the voltage issue the surge protector wouldn't even "allow" the shore power to pass through.  With that said, I believe I found the solution after I talked with a Progressive Industries tech.  They said the voltage setting can sometime drift and as long as a person is comfortable with opening the unit, an adjustment can be made to the setting using a mulltimeter to display the voltage being supplied and compare it to what the unit displays.  If its off by more than a couple of volts it can be adjusted to the correct level.
In my case, voltage in was around 117 to 118 but the display was showing 109.  I adjusted it up and now I was able to run a couple of loads with no problem although I haven't tried the A/C since the circuit is only 15A and I don't have a soft starter.