Charge Controller/Converter issue?

[calveryc]

I'm new here, thanks for having me. I'm also new to RV'ing and have run into a confusing issue with a new to me RV I bought a few months ago. While hooked to a generator I noticed my box fan seemed to be running at half speed. I checked my generator and it's putting out 120v but when I checked my 110v plugs in the RV I found something odd, when I went from ground to hot I got 65V, when I go from ground to neutral I got 65V, when I go neutral to hot I get 120V. Is this typical of RVs? In a home your neutral to ground should be 0, ground to hot should be 120V. If this isn't typical is this a symptom of a bad charger controller? Anyway thanks for the help.

[3_tons]

Wa8xym, That is a mighty fine explanation Sir, thanks for washing my windows 🙂 !!

3 tons

[Fisherman]

Bond the Generator outlet if it allows or make a special generator adapter with neutral and ground bonded.. IF YOU DO NOT KNOW HOW. Get help from someone who does.

Take a common 120 volt AC plug, open it up and put a 14 ga jumper wire between the green ground screw and the silver screw where the white or neutral wire goes. Close the plug and insert it into one of the 120 volt receptacles. Now it's bonded. It was mentioned here before with a couple of pictures but I can't find it.

[wa8yxm]

calveryc wrote:
I checked my 110v plugs in the RV I found something odd, when I went from ground to hot I got 65V, when I go from ground to neutral I got 65V, when I go neutral to hot I get 120V.

100% normal when using a portable generator.. WHY you ask?

In electronics there is a device called a capacitor. and another device consisting of two capacitors called a "Capacities voltage divider" This is like a resistive divider in a DC circuit.

Now imagine the following DC hook iup

12 volt----100 ohm resistor--X--100 Ohm Resistor--Ground (Returns to battery)

The two identical resistors will divide the voltage so the voltage at point x (assumign no load) is six volts 1/2 the battery.

Well in an AC cucuit it works the same way with Capacitors

120 V Hot----||----X-----||----- Neutral

The || is the symbol for a capacitorl it is also how they are built

Two metal plates with an insulator between them

You have how many feet or ROMEX in your house on wheels

Romex is three wires side by side. the hot is on one side neutral on the other and ground in the middle

Makes a capacitive divider

HOW TO FIX

Bond the Generator outlet if it allows or make a special generator adapter with neutral and ground bonded.. IF YOU DO NOT KNOW HOW. Get help from someone who does.

[calveryc]

I would like to thank you guys for helping me and not being condescending to my newby questions.

[DrewE]

Most portable generators do not have the ground wire bonded to the neutral wire, and indeed have the output floating with respect to ground. (This ground is also rarely an earth ground since one doesn't tend to install or attach to a grounding rod, but that's immaterial).

AC appliances only get power from the hot and neutral lines, so the voltage there is all that matters for their operation. 120V there is normal. Seeing 65V between the ground pin and hot and neutral just indicates that the ground line, not really connected to anything, is tending to float about halfway with respect to the power lines, and that's about what one might expect. If you use one of the three light outlet testers, it will indicate open ground, which is also expected since the ground and neutral are not bonded together, which is what it is actually detecting.

("Bonding" in this discussion simply means having the two lines shorted together at their source; in a house, this generally happens at the service entrance or the main electric panel. In an RV with a built-in generator, the built-in generator bonds the neutral and ground lines at the built-in generator, but portable generators usually don't have a bonded output for electrical code reasons that don't really matter here.)

Your fan problem is unrelated to these 65V measurements.

[calveryc]

Ed_Gee wrote:
Here is some relevant info taken from the Champion generator web site:

" What does "Floating Neutral" on My Generator mean?

Most Champion Power Equipment generators have a "floating neutral", meaning that the neutral circuit is not connected to the frame or to earth ground. This also means that both legs on the receptacle are hot legs, which is normal for floating neutral generators. As a result, there is no specific hot leg and neutral leg wiring arrangement for the generator winding connection to the receptacle. The floating neutral configuration is common for applications such as connection to a recreational vehicle and connection to home power where the transfer switch does not switch out the neutral to ground connection.

The floating neutral eliminates the potential of being shocked by contacting a hot leg and the generator frame at the same time, which could occur if an electrical device such as a hand held tool suffered from an internal short circuit.

Meters or other devices intended to indicate polarity may not properly indicate polarity on a floating neutral circuit. Polarity indicators generally measure the voltage across the neutral and ground connectors. In electrical systems where the neutral is bonded to ground, the voltage will be zero and correct polarity will be indicated. In systems where the neutral is not bonded to ground, voltage is also not expected across this connection. However, in a portable generator some very small current voltage readings can be recorded by sensitive volt meters. This voltage may be induced in the frame by the magnetic field of the generator. The current associated with this induced voltage and the risk of electrical shock are negligible. However, very sensitive polarity meters may interpret this voltage as an indication of reversed connections.

If you have an indication of reversed polarity, please check with the manufacturer of your meter to determine if that reading capability applies to the floating neutral output from a portable generator. "

Thank you.

[opnspaces]

If you unplug the cord from the generator and use your meter on the running generator outlets do you get the same 65v readings? Is there something printed on the generator that alludes to neutral and ground being bonded?

[Ed_Gee]

Here is some relevant info taken from the Champion generator web site:

" What does "Floating Neutral" on My Generator mean?

Most Champion Power Equipment generators have a "floating neutral", meaning that the neutral circuit is not connected to the frame or to earth ground. This also means that both legs on the receptacle are hot legs, which is normal for floating neutral generators. As a result, there is no specific hot leg and neutral leg wiring arrangement for the generator winding connection to the receptacle. The floating neutral configuration is common for applications such as connection to a recreational vehicle and connection to home power where the transfer switch does not switch out the neutral to ground connection.

The floating neutral eliminates the potential of being shocked by contacting a hot leg and the generator frame at the same time, which could occur if an electrical device such as a hand held tool suffered from an internal short circuit.

Meters or other devices intended to indicate polarity may not properly indicate polarity on a floating neutral circuit. Polarity indicators generally measure the voltage across the neutral and ground connectors. In electrical systems where the neutral is bonded to ground, the voltage will be zero and correct polarity will be indicated. In systems where the neutral is not bonded to ground, voltage is also not expected across this connection. However, in a portable generator some very small current voltage readings can be recorded by sensitive volt meters. This voltage may be induced in the frame by the magnetic field of the generator. The current associated with this induced voltage and the risk of electrical shock are negligible. However, very sensitive polarity meters may interpret this voltage as an indication of reversed connections.

If you have an indication of reversed polarity, please check with the manufacturer of your meter to determine if that reading capability applies to the floating neutral output from a portable generator. "

[calveryc]

Could be. I just checked the generators digital readout and it says phase 66.1

[3_tons]

Since you’re reading 65v at ground to hot, and 65v from ground to neutral, it ‘may’ be indicating the effects of each half wave, but thats just a best guess...Does the box fan run at full speed when plugged into the stick built house??

[calveryc]

opnspaces wrote:
Also check to see if the problem occurs at the generator itself or is it only in the trailer? What's the rated output of the generator? Is it a 2000 W model or something smaller? Is there a make and model on it?

Are you able to plug temporarily into a household outlet and see if the readings are the same?

It's a 3650 watts continuous Champion.

[3_tons]

When trying to chase down an electrical issue (of which I can no longer recall...) I ran into this exact same 65v gremlin a couple years back, but could never interpret it’s causation... What ever the cause, I could only write it off as a phantom meter reading as it turned out to be unrelated to the primary issue (??) at that time...Wish I could remember more details, but the 65v oddity still sticks in my memory...Though to my knowledge it hasn’t raised its ugly head since, I’m still a bit perplexed by this occurrence...Now that I read about this here (a validation), there must be some combination of sinusoidal events (half wave??) that can result in this kinda reading...

Now I have something to think about in all my new found spare time - thinking cap ON - lol!

On edit, I now believe this reading arose when running the genny (Honda 2000), but voltage at the inline killawatt meter (genny outout) remained normal at all times...

With the OP’s post, now I won’t rest - dang !!

[calveryc]

opnspaces wrote:
No it's not normal and potentially dangerous. What kind of RV are we talking about, a motorhome or trailer or truck camper? Is the generator built in or a portable?

If a portable check if the shore power cord has a replacement end on it. If so unplug and disassemble the plug and make sure there are no stray wires jumping from screw to screw and allowing a voltage leak.

Checked the cord and it doesn't have a replacement end on it.

[BFL13]

Here we go with "bonded", Earthed", "grounded", "floating neutral". Get some popcorn!

Don't know about the box fan at half speed.