Noise on 12v line
 

I have massive noise on the 12v line on my FEH. Anytime I plug in an audio device that powers from the 12v outlet there is a huge hum. As this seems related to the car functions (tapping the brakes exaserbates the problem) I doubt a line filter will do much.

Any one else see this or have a suggestion.

A DLO Transpod is what I am trying to use but there is too much buzz.

FYI, charging the ipod with 120v is clean (as that makes sense).

Thoughts?

-dsd

Re: Noise on 12v line
 

Hybrids will produce a lot of RF and HF noise because of all the processes that are involved with computers, motor controller, power inverter, etc. If possible, try to run a FUSED 10 or 12 gauge +12v and ground twisted pair wire (twisted as tightly as possible using a hand drill) directly from the 12v battery to the 12v accessory outlet. This may help. You can also try and place the twisted pair in a metal braided cable jacket/sleeve, available at most electrical/electronics suppliers. Connect the sleeve to ground.

Hope this helps.

good luck

Re: Noise on 12v line
 

I have never had any noise issues in either FEH whether I use the 12v plug on the dash or on the console. I use a cheap ($30 at Target) MP3 player that plays directly from a USB type chip and have been perfectly happy with the quality I get.

Have you tried both power ports? I know one is intended as a cigarette lighter but it works the same.

Also, is the noise any different when the ICE is running compared to when you are running in EV mode? What about with everything shut down? This may help narrow down the source of the interference....

Re: Noise on 12v line
 

You have a ground loop- the grounds for the inverter and 12v accessory outlet (maybe entire 12V system) are not properly isolated and 60Hz or a harmonic are leaking through to what should be a pure DC circuit. (All grounds are not the 'same' ground).

This will NOT be a repeatable problem car-to-car. Every one has a slightly different grounding, and the loops will be different depending on temperature, exactly where the connection was made, etc. Its also not something that can be predicted beforehand with certainty- the nonideal nature of electric circuits requires a little tweaking sometimes.

Note to the paranoid among us: THIS IS NOT A SAFETY PROBLEM!!!!! ground loops are on the order of millivolts and microamps- well below the normal signal levels present even in speaker cables.

Ground loop isolators are easy to buy for audio, TV cable, etc that have AC flowing through them. DC circuits just need to run straight back to the source- the 12V battery, here.

Securing a proper ground for DC is to do what ralph mentioned- simply run the outlet straight off the battery. In all likelihood you will not need to twist or shield this new wire too much- its not likely to pick up very much radiation form the inverter unless you run right by it. But the shielding won't hurt.

Note- this will keep the 12V outlet powered all the time- like in an older car (I assume the FEH cuts power to 12V outlets like most do today?).

Re: Noise on 12v line
 

Thanks. I though it might be a grounding issue or frequency distortion. As I don't have much time these days, I made an appointment at the local car radio experts shop and they will fix it for well under $100 (p&l).

I will let everyone know what the end result was if someone else has an issue, there will be a fix (at least what I find out).

Thanks all,
dsd