View Full Version : Houston I Have A Problem

19 September 2012, 1055
Well after watching Teds video, i had to go for a little ride "around the block" despite that i have no license plate yet, of course who would be parked in the turn around, but a police officer - anyway thats not my problem and he didnt do anything, just waved...

:( anyway i just installed a FM stereo to the bike, but when i give the bike the throttle, my radio station goes away - when i let off the throttle the station comes back in... i know its the EMF from the controller or motor - is there a filter i can get to stop the interference???

19 September 2012, 1216
i heard cable radio is less prone to interference

...wait....no...i'm not sure it would work here.:confused:

19 September 2012, 1254
i just installed a FM stereo to the bike, but when i give the bike the throttle, my radio station goes away - when i let off the throttle the station comes back in... i know its the EMF from the controller or motor - is there a filter i can get to stop the interference???

You need to shield the EMF at the source. If you shield the radio, it won't get any signal at all.

Shielded battery and motor cables might help. Not cheap.


Or, just get an mp3 player...then you can listen to what you want (I hate FM radio).

19 September 2012, 1313
it does have a mp3 player input - Thank You Noah and Hugues...

and i'll try getting a shielded cable set anyway, for later on down the road - 12 dollars a foot isnt that bad considering the money i got into bike already...

19 September 2012, 1350
In the late 80's when the E-meter and KWH-meters were first being installed in EVs I used to ask what their favorite radio station was just to get that look. The vehicles then would black out your neighbor's TV and radio. A brushed motor with a poorly filtered controller makes quite a racket!

Two types of noise, conducted and emitted. Test emitted with a handheld radio next to your bike, test conducted with a spare (isolated) battery and NO ground connections on your radio on the vehicle. Emitted will be tough to eliminate, but conducted is pretty easy. Usually the brushed drives are fixed frequency and that noise source could be notched out but brush arcing is all frequency. AC or brushless drives are variable frequency and need their own internal noise measures.


19 September 2012, 1433
I think that is a safety feature to prevent distracted riding due to listening to political advertisements on your radio. :p

19 September 2012, 1510
A radio on a motorcycle? Mmmmmmmmmmmmmmm

20 September 2012, 0715
Yep, along skahle's line of thinking, I would not be surprised if most of the noise you are getting is being conducted through the circuits of the bike - if that's the case, it should be feasible to isolate the radio from the RF. I'm running a brushed DC motor with a Kelly controller, with no additional shielding and have no interference at all with FM radio - but the radio is built into the bluetooth headset in my helmet and electrically independent of the bike.

20 September 2012, 0753
:D i know Ed - but i have this thing about listening to music while riding - AC/DC gives me five more horespower...

20 September 2012, 0756
yup Bill, my stereo is wired to the 12 volt system of the motorcycle - but if it doesnt interfere with a mp3 player then that will work for now...

20 September 2012, 0850
The other thing about listening to music on an electric motorcycle is that it is a lot easier to do than if the music has to compete with an IC exhaust. Well, maybe the theme of Easy Rider might sound better with a loud rumble in the background. :rolleyes:

20 September 2012, 0911
i know i can record AC/DC with a HD in the background...

20 September 2012, 1002
As was previously mentioned, if you want to solve the problem, step 1 is to place a little battery powered radio in the same location on the bike (tape it on or something), go for a ride, and see if you experience the same noise issue. If you do, it's radiated noise. If you don't, it's noise on the power to the radio.

Until you know which type of noise you're dealing with, you don't know which approach to take for fixing it. Both are solvable, the conducted noise being the most simple to solve completely, radiated noise being easy to reduce, but difficult to stop entirely.

20 September 2012, 1104
Hey liveforphysics, glad your back - that would be and easy test, i have an old walkman radio i can try that with - i havent tried the cell phone thing either...

21 September 2012, 1036
Well i put the motorcycle up on the jack stand - turn the radio on before the power was applied to the controller - stereo sounded fine - i gave power to the controller, again the stereo sounded fine - i gave the motor some throttle and it blocked the stereo signal, as soon as i released the throttle the stereo signal came back in...

then i tried a walkman radio, same result except for when i gave the motor some throttle, the walkmans signal barely dropped at all, then i place the walkman on the saddle of the motorcycle which is right above the motor and the walkman signal still came through just fine...

and then i measured off 10' from the motorcycle and used a cell phone while the motor was running and had my associate walk towards the bike, at three feet away the phone got a bit of a static, standing right next to the motorcycle the cell phone still had a signal but with a bit of a static to it...

so all in all, only the stereo mounted on the handle bars lost its signal...

21 September 2012, 1122
I assume you're running the radio of the DC-DC. Is your DC-DC isolated?

21 September 2012, 1143
Noise coming through the power cables from the controller.

If you do have an isolated dc-dc then maybe there's a ground path you don't know about.

21 September 2012, 1241
well the 12 volt system is running off a separate ground and battery system "AGM"...

the motor, controller power "LiFePo4" is completely separate from the lighting and radio power system, two different battery entities...

but the controller is very close to the handle bar just under the fake gas tank...

21 September 2012, 1253

here is a photo of where the controller is...

21 September 2012, 1418
depending on the radio it might not be seeing chassis ground through the frame or your antenna might need the base grounded.