Classic causing awful noise on AM radio

[nfenergies]

Hello all:

My first post here, so please excuse any poor etiquette and feel free to correct/criticize.

I have a user who is experiencing extreme interference on AM radio bands since adding a Classic 150 to his power system.

Previous controller(s) were PWM.

The radio is a Sony car deck powered by one stand alone car battery.  A small antenna extends to the roof.  The battery is near the Classic and the radio is up on the next floor.

When we power up the Classic, the whining begins.  As I close breakers for PV inputs, the whining increases in frequency and intensity it seems.

Please help!?!  Thanks.

[boB]

Sounds like it might be radiating mostly from the PV lines.

How close is the antenna cable running upstairs from the PV cable ?
If it is close, that is probably why.

Can the PV wires be somewhat twisted together ?  Is the chassis
of the Classic grounded ?

This is probably going to take a combination of moving things around
some and maybe a ferrite toroid or clamp on around the plus and
minus PV wires (both through the same ferrite).  That ferrite will
want to be close to the Classic, if not inside the wiring compartment
if possible.

The AM broadcast band is a pretty tough one since it is low frequency
and the wires are so long for the radio and the PV from the Classic.

For low frequencies like AM broadcast EMI suppression, Type 73 material
is probably best (or equivalent)

But this core and type from Wurth looks like it's the really good stuff !

http://www.mouser.com/ds/2/445/74272722-15911.pdf

But it's not cheap at $15 or so from Mouser or Newark.

Since we're on the subject, here is a paper on the subject for you and
others.

http://fusion.midnitesolar.com/Chosing_Ferrites_For_EMI_Suppression_CUP%2520Paper.pdf

If you can fit it in, it's better to wrap more than one turn of the pair of wires through
the ferrite for more EMI reduction.

I'll post more soon if I think of something more.

boB

[niel]

additionally you could place more than 1 of the torroids inline and the more the merrier with as many turns of the wire through them as you can get. maybe boB knows best that it's probably on the pv leads being radiated, but it could be conducted as well up from the battery leads so it may be good to put some torroids there too, but preferably as close to the classic output as is possible. got a battery operated portable am radio to place near the pv leads or along the battery leads to act as an rfi detector? if you don't hear it or it is much weaker on the portable from the battery leads then suspect it to be conducted from the battery leads. hear it on the pv leads strongly or weakly then it is radiating from there. check all connections to be good and tight and be sure there's no corrosion on them.

as boB started into saying the proximity of the pv wires and/or battery wires to the antenna or the antenna lead-in cable can cause problems so move them apart as much as you can and do not have them run parallel to one another if at all possible.

you also state it to be a whining. is this on the entire band or just in a few spots?

[phonetic]

I have a HF receive setup, antenna 100 feet away from PV array, using TDK ferrite 8mm clamps on all leads connecting to classics.
I don't have problems with RFI.
Try using a portable AM radio to confirm where interfence is coming from.