While I don't think we have a problem, I find this situation perplexing.
We have a Xantrex ProSine 3.0 and a Progressive Industries EMS-HW50C.
Only in the evenings do I see this happen. Right now the Xantrex display panel shows incoming voltage for Line 1 - 140V. Line 2 - 139V.
The readout panel for the Progressive Industries EMS reads Line 1 - 125V. Line 2 - 125V
Does any one know why this happens?
We don't have a Progressive EMS for comparison, but when we have had unusually high voltage readings on our built-in coach monitoring panel (we have the Xantrex 2500, IIRC), the problem has been either a poor ground connection in the campground or another unit on the same leg/circuit of the campground which had a wiring problem, polluting the ground. When this happened, our Surge Guard indicated a "voltage on ground" error.
We've also seen a flickering red LED on the built-in coach readout when this occurred.
Voltage is a funny thing - it's actually a difference measurement, not an absolute one. So 125V is 125 volts above what the reference is (which should be 0 on ground). Once can still have 125V difference between a voltage leg and "ground", yet if there's a phantom voltage on "ground", either because the connection isn't good (ground is "floating") or there's a miswired rig on the leg, then a unit which "assumes" 0 voltage on ground will display a higher reading.
So let's say there's a phantom 15 volts on Ground. The voltage leg would be 120-125 volts above that, but a readout which assumed Ground was 0 would actually display 135-140 Volts.
In your case, if possible I would check on moving to a different site that's possibly on a different electrical circuit/leg unless the problem suddenly showed up with a particular rig's arrival (we had this happen). It's a small but possible safety concern.
Michelle
George.... I have noticed the same difference. I have one of the portable EMS units and it normally reads lower, voltage-wise, than the Xantrax unit in our 2003 U295. I think it is a Prosine 3.0. Normally I check the voltage before I plug in with another voltmeter, but I don't recall which is closer (EMS or Xantrex) to the voltmeter. Note that I see this difference without any obvious problems as shown by my RV circuit checker (see previous posts) or the EMS unit.
George
What I reported as a difference in the read out between the EMS digital readout and the Xantrex panel was incorrectly described.
Here is my error. I was looking at the 10-year-old and original "Power Line Monitor" bearing the Foretravel name and logo. It is this device that is giving erroneous information.
When using a voltmeter (thanks, George Hatfield) and comparing it to the Progressive Industries EMS digital readout, I am within one volt between the two. I will be more careful in future postings.
:(How long do I have to sit in the corner? :-[
George..... I made the same mistake. The Xantrex panel does not have the line voltage readings. It is the panel next to it (Power line monitor, Foretravel).
George
I was moments away from calling Xantrex and asking for warranty service, but decided to take one more close look at the panel and discovered my mistake. A real "DUH!" moment. It is comforting to know that I have company.