Low Voltage Question on House Battery and in Transit

I have a digital voltage readout on 3 of my outlets. The outlet in the bathroom seems to always show a lower voltage read out than the Xartrex when on shore power and on the house batteries with out shore power and on the road under way. The bathroom will show a range of 99 to 117 volts when we are on house batteries and when we are on the road at hwy speeds. Can anyone shed some light on why the Xartrex xml1800 monitor behind the driver seat  shows 13.6  and 13.3 volts when traveling on the road and on shore power. and the lower voltage read outs in the bathroom?

I never checked our 110V outlets pending the various power sources, but I am not too surprised to read of the variations.  The next time our rig is operating, I'll have to run around and check the voltage on each 110V outlet and see what we have.

The bathroom has a GFI outlet.  I wonder if the GFI feature influences the voltage there.

I have a digital voltage readout on 3 of my outlets. The outlet in the bathroom seems to always show a lower voltage read out than the Xartrex when on shore power and on the house batteries with out shore power and on the road under way. The bathroom will show a range of 99 to 117 volts when we are on house batteries and when we are on the road at hwy speeds. Can anyone shed some light on why the Xartrex xml1800 monitor behind the driver seat  shows 13.6  and 13.3 volts when traveling on the road and on shore power. and the lower voltage read outs in the bathroom?

I am a bit confused, you are reading AC voltage output at the outlet, but the Xantrex panel is reading DC voltage input.

Presuming you are using the same AC voltage meter when you test the outlets, different voltage readings on the various outlets would indicate possible corroded connections in the circuit breaker panel or the outlet itself.

As to the DC voltage shown on the inverter control panel, that's an indication of the state of charge of the house batteries.   That DC voltage should rise to 13.8v with the batteries fully charged.    This all presumes that the battery terminals are not corroded and the cables are tightly attached.    Also battery age can play a role.

As to the DC voltage shown on the inverter control panel, that's an indication of the state of charge of the house batteries.   That DC voltage should rise to 13.8v with the batteries fully charged.    This all presumes that the battery terminals are not corroded and the cables are tightly attached.    Also battery age can play a role.

Very true!

Also, having just one light on or other small draw will lower that 13.8v voltage reading.  And it seems motor homes always have some kind of minor draw-down.

Also, there is a 40amp, self-resetting circuit breaker inside the hood, on the inside of the driver's side wheel well.   That breaker is what feeds the alternator output to the house batteries to charge them while the engine is running.  That could be another reason the DC input voltage doesn't get to 13.8v while going down the highway.

Those circuit breakers are known to "lock" in the open position so your house batteries won't charge while you drive.   

They look like this.. About 1 x 0.5 x 0.5 inches:

Ok I see I was not understanding the State of charge on the Xantrex value of 13.8 nd the “AC” output value of 110 or so on the AC outlets. So what should I see on each AC outlet as I move my meter to each AC outlet . If my bathroom AC outlet says 99 volts and my AC outlet in the kitchen says 110 volts what does that mean Corrosion ? Or parasitic draw from some other source. ?

What Numbers are you seeing on your coach at each outlet when in transit or on and house batteries ?

Ideally, no difference in voltage over the various outlets.  In reality, perhaps a volt or two.  Properly wired, no outlet on a unit as small as an RV (short lengths of wire) should never have a 10% voltage drop across different outlets attached to the same main power source.

Corrosion is the number 1 cause added resistance in a circuit.   Corrosion can occur because of many factors, the most common being improperly connected wiring terminals.    Not tight enough so arcing occurs when a high current load is turned on... Such as a toaster, electric heater, hair dryer, etc. 

I would check connectors in the 120v portion of fuse box and in the bathroom outlet.    ALL POWER REMOVED FIRST!  If necessary, get a qualified electrician to check the wiring.

Have you tried using one voltmeter  to check all the AC  outlets to eliminate the possibility of a miscalibrated or defective digital readout device? Have you checked  all the  outlets on shore power  with the inverter switched off?  Most multi-meters, either voltmeters or ammeters, measure RMS value assuming a pure sinusoidal waveform. What type of waveform does your Xantrax inverter produce? Are your digital voltage  readout devices fully compatible with a modified sinewave?

Read this.  It might explain voltage drops around your PC.

Has anyone removed one of your 110V outlets in your PC and seen how the wires are connected to it?  It is NOT impressive.  At least it is not so in our 2007 PC.  Our 110V outlets and the cover plate is all one piece which might be the indicator of the goofy outlet wire terminations.  The back side of the outlet is not enclosed and the wires are attached in a way I have never seen before.  If there is an intermittent connection, we might have a fire, especially with the inverter on while driving.  The vibrations and sparking & arcing from them might make the perfect storm.

I have been meaning to go though our rig and replace every 110V outlet with conventional house ones that I can tightly screw the 110V wires on.