Battery Charger

[Weewun]

Have just purchased a 2007 Monaco Diplomat.  Have very loud humming when the Battery Charger is turned on.  The Battery Charger is a Magnum Charger/Inverter. 

This Model uses the Chassis  Radio as the DVD Player and has a unit that for the Surround Sound that feeds all the Speakers.  I had the same Magnum Charger/Inverter in my 05 Monaco and had no humming but then my Surround Sound was provided by a stand-alone DVD/VCR 110 volt unit. 

Was wondering if the DC from the Magnum is so dirty that it is feeding thru the 12 volt Surround System.  Went into two other 07 Monacos and they had the same humming. 

Am thinking that maybe a 150 microfarad capacitor across the power terminals may clean up the power.

I will appreciate any input concerning this problem and if anyone knows of a commercial filter that has solved this problem, plz advise.

 

[John From Detroit]

Ok is this humming FROM THE CONVERTER (If so see note below) or from the speakers.  I will assume, since you took the time to tell us about the speakers, it's the speakers. 

The converter converts 120vac into 120 vdc sort of, (it's almost 120 cycle ac, with a strange waveform) this is the HUM you are hearing.  The converter relies on the battery to smooth out the 12 volt, into 12volt DC

The fact you are hearing a humm in your speakers means that there is no condensor in the output of your converter (Progressive dynamics, by the way, filters the converter output, on it's products) (hint)

And either 1: The battery is DEAD! and I mean DEAD! and thus sucking down the max from the converter (if this is the case time will fix) or two there is a high resistance connection somewhere, Prime canidates are the battery connectors, the other end of the same cable, and from there any cable between the battery and the fuse block where the radio hooks up

Also, your Battery disconnect switch.  If you have either 1: Disconnected the batteries, or 2: Bad switch,  HUM

Almost forgot the note below

If the hum is hte converter itself, and not the speakers it's the transformer laminations ratteling, normal, don't worry unless it is so loud as to annoy

 

[Weewun]

Thks for the input. 

The hum is definitely from the speakers, I can turn off the Surround Sound and the humming stops or I can disconnect the audio leads coming from or into the Video Switch and the humming will stop.  Both the SS Amp and the Video Switch have DC Filters on them (have not verified that the Gnd wires on the filters have a good chassis connection).  Also, have not verifid Gnd for the TV set which is the audio input for the Video Switch. 

Have not checked the charge condition of the House batteries.

I feel that it is the gnding of the various components since it occurs on all the other Monaco here at Lazydays.  Lazydays is prepping the new Coach and their initial reaction is "all of them do it."  Am on my way back over to do battle with them as I will not accept the Coach as it is.  Thks for listening.

 

[Gary RV_Wizard]

Since it's an 07, I suggest you complain to Monaco under warranty.  There is no way an expensive coach like that should have speaker hum, especially if its interference form the Inverter/charger.

 

[John From Detroit]

I'm talking a POWER ground, espically the batteries.. Or as I said, the battery disconnected.

That hum is most likely unfiltered DC out of the converter, should not make it past the battery

 

[Jim Godward]

If the inverter is a Xantrex inverter there is also radiated emissions and there is probably no good way to get rid of them.  Been there, done that!! 

If you want to get serious, all wires need to be shielded twisted pair and the shield grounded at both ends to the componet, no openings at either end.  The case of everything must be grounded and coaxial capacitors on the input and output of all wires too.  With luck and perseverance you may get there. 

The easy way is to turn off the charger! and maybe the inverter too!! 

BTW, Xantrex is "not responsible" for these emissions, the owner of the unit is.

 

[John From Detroit]

I was thinking CONVERTER, not INVERTER but re-read, it's not an Xantrex, it is a Magnum.

If it is a modified sine wave inverter, the hum may be due to the difference between a modified sine wave and a real sine wave (True sine wave)

I have a Xantrex True sine wave inverter/charger in my house on wheels, and I can not hear any radio interference. Not on the TV's, not on the home theater, not on the Kenwood TS-2000 and if it was there... The Kenwood would find it, For sure it would find it.

(That thing covers frequencies from AM broadcast to UHF)

But if you are running off the inverter.. And it's a MSW.. that's your problem

Folks keep tilling me that "Oh, MSW inverters are just as good as true sine wave"

Yea, right.  Trust me, they are not