Vintage Car LED Headlights and radio static

[RalphWiggam]

Has anyone else installed these LED headlights? I installed my set this past weekend. I just noticed last night when driving home that whenever I turn the headlights on, whatever radio station I am listening to immediately goes to static.

I googled the issue and apparently this is a known issue with LED lights. Apparently if the LED driver circuit is not designed well, this is exactly what happens. There also appears to be nothing you can really do about it.

Has anyone else experienced this? Any ideas? I really love the extra light output, but I dont know if I can deal with this static issue.

[SGKent]

Ralph - are you listening to AM or FM when you hear the static? Does FM have t he static is what I am after.
_________________
“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[ccpalmer]

Who listens to AM anymore?!?
_________________
'71 Westy

[SGKent]

[RalphWiggam]

[Q-Dog]

Interesting. I have a couple of 12 volt lights in my kitchen ... they shipped with halogen bulbs. I replaced a couple of the bulbs with LEDs and they cause a few channels on my TV (over the air antenna) to dissappear when the lights are on.
_________________
Brian

'69 Dune Buggy
'69 Beetle Convertible
'70 Beetle

[SGKent]

so - FM is frequency modulation. AM is amplitude modulation. If AM is being affected really bad on all AM radios nearby the transmission is usually thru the air. FM is more selective in how it listens to random noise - that is why FM is considered quiet compared to AM. You don't hear lightning strikes in FM normally, and you don't hear an old flat head Ford with copper ignition wires drive down the street with FM like you do with AM. Unfortunately the RFI (radio frequency interference) in some LED drivers does emit FM in the same band as FM radio. Stopping that RFI is harder than stopping a signal that is getting to the radio through the power wire. Things that come to mind are to shield the drivers. This could be done by wrapping them in aluminum foil or a metal housing and grounding it well - making sure that the aluminum foil is not touching any circuits. If the drivers are already in a metal housing make sure it is well grounded. You can also hold an FM hand held radio nearby, or another car with FM when you are done and see if it has the same issue. If it doesn't but your car still does, then you can build a RF filter into the power cable for the car radio that passes 12V but blocks the RF and shunts it to ground.

Or you can go back to halogens, or try a different brand LED.

I'll ask Telford to take a look too.
_________________
“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[telford dorr]

This is becoming a chronic problem these days, as nobody watches (highly susceptible) analog over-the-air tv anymore, thus awareness of the problem is disappearing. There are FCC regulations relating to RFI emissions, but they seem to be universally ignored (unless someone complains). Legally, no device may emit radio frequency noise above a certain level. The problem is more severe with digital electronics made in other countries (take a guess where...)

Any digital device is a potential RFI emitter. The problem can be controlled by the use of filtering, shielding, and by limiting waveform risetime. This isn't all that hard at circuit design time, but after-the-fact correction can reach impossible levels. Some possible modifications are: adding series inductance by placing ferrite beads around power feed wires, installing feedthrough capacitors inline on power feed wires, and adding metal shielding around the circuitry.
_________________
'71 panel, now with FI
'Experience' is the ability to recognize a mistake when you're making it again - Franklin P. Jones
In theory, theory works in practice; in practice, it doesn't - William T. Harbaugh
When you're dead, you don't know you're dead. The pain is only felt by others.
Same thing happens when you're stupid. - Philippe Geluck
More VW electrical at http://telforddorr.com/ (available 9am to 9pm PST)

[cmonSTART]

From someone who is into Ham Radio as a side hobby a lot of newer LED units do emit RF interference. My barn lights are LED and I can "hear" them on a couple of wavelengths - quite loudly.

You can research ferrite beads and baluns - I don't quite understand it all but there are ways to choke off RFI.
_________________
'78 Bus 2.0FI
de K1IGS

[my59]

[RalphWiggam]

After testing some more tonight it seems like the headlights only affect certain frequencies. Pretty weird. I can seek through all stations and some won't have any static with the headlights on and some will be all static (only with the headlights on).

Some down in the 88.x and some up top in the 106.x range. So it's not a specific range issue.

Based on this, I'll probably live with it since the increase in light output with the LEDS is more important to me.

[richparker]

If you absolutely can’t live with it, the Hella H4 headlights (I got mine from BD) are really good IMO. I can see the wildlife well in advance, I’m very happy with them.
_________________
__________
’71 Westy build
Adventure thread
’65 Deluxe Build
’63 Deluxe Build

[busdaddy]

Sounds to me more like a weak antenna connection or it needs trimming (if your radio has that option), or possibly the antenna isn't grounding to the body well where it mounts. The interference from the new headlights just exposed an existing problem.
_________________
Rust NEVER sleeps and stock never goes out of style.

Please don't PM technical questions, ask your problem in public so everyone can play along. If you think it's too stupid post it here
Stop dead photo links! Post your photos to The Samba Gallery!

Слава Україні!

[telford dorr]

Most likely the headlights are using switchmode current regulation in the LED drivers which have fast risetime waveforms, thus radiating RFI. If it's radiating on the power lead to the light, ferrite beads on the wires to the headlight might calm it down a bit.

Scrounge up an old 60's vintage working transistor AM radio. Tune it to a blank space between stations. Maneuver it around the operating headlights and the wires going to them. See where the loudest buzz occurs.
_________________
'71 panel, now with FI
'Experience' is the ability to recognize a mistake when you're making it again - Franklin P. Jones
In theory, theory works in practice; in practice, it doesn't - William T. Harbaugh
When you're dead, you don't know you're dead. The pain is only felt by others.
Same thing happens when you're stupid. - Philippe Geluck
More VW electrical at http://telforddorr.com/ (available 9am to 9pm PST)

[jlrftype7]

[panic_fan]

Since I give off so many emissions driving the bus around town. I figured I would install some LED's in my garage to reduce my footprint.

Come to find out they interfere with my garage door opener. When the lights on, the remote wont work....

Oh well, I tried.
_________________
Rich
Brilliant Blue/Cloud White
1970 Baywindow Bus
http://www.thesamba.com/vw/forum/viewtopic.php?t=291988&highlight=


"Still learnin the way around my VW bay"

[SGKent]

[raygreenwood]

ALL LED lights emit some interference.

Look carefully at many new circuit boards that have LED function lights....that you strip out for dissection fun after the Chinese...and made anywhere products...they are in.... fail

If the device or circuit is going to sensitive to RFI....a device that is compliant...will have added bits and pieces on or around the PCB to take care of this.
They typically have to meet standard CISPR15 specs.

These can be anything from the already mentioned ferrite beads on wires or doped plastic sockets or dielectric overprint inks that contain barium ferrite or other shielding minerals, or small beads around the leg pins ofsurface mount components on the boards.....and they work....if the area these treatments are used on...are the actual source of the RFI.

You have these three possible causes of RFI with LED lamps. Each one can require a different solution to fix the noise. It may be some of several of these.

1. The lamp itself...and this is usually caused by an electromagnetic compatibility (EMC) issue with the power source if the bulb is a quality brand like Phillips or Cree or many others. So it may be that the LED emitter frequency is mismatched with the power frequency.

2. Or it an be an actual case of something emitting RFI. This is EMI (electromagnetic interference)....this can be the bulb, the ballast (if its using a ballast with conversion circuitry) or the transformer. Either way its hardware if its doing this.

3. Conduction radiation (coupling path). Sometimes listed as interference between "source and victim" (just read this in an IPC paper a while back). In the case of home or building installed LED's...it can be a resonated signal issue (only way I can explain it) between the light source/bulb and the light fixture (luminaire) its mounted in. To better explain that....think of all of the metals involved in making a reflector for a bulb....chrome, aluminum, tin, various vapor dep'd dopants etc....which when exited by some minor amount of RFI signal from a bulb...may reflect a totally different/augmented signal.

Or....it can be the wire/cable....creating basically its own electromagnetic coil. Excessively long runs can do this. Or in a building it can be the ceiling itself and all of the crap and material in it...reflecting a small signal and creating a larger one....essentially just absorbing some EM spectra and not others.

The only common fixes listed for these are to
A. make sure you start with a quality bulb...brand name. If these LED headlights use some kind of no name bulb...as others have noted....its construction may not be meeting any compliance levels.

If your LED headlights do not use a replaceable bulb....ditch them. Why would you use a lamp that requires replacing the system when one burns out...and they will.

B. Check the specs on the transformer....and all LED's...even 12volt LED in a 12 volt system ...have some kind of transformer even if its just a rectifier to keep voltage stable. If its not a transformer MADE for LED's....replace it. Lots of places you can buy LED specific transformers with the right shielding.

C. Use shielded cable. If your system dose not use RFI shielded wires from power source to light socket....replace them.

D. Get a ferrite bead, ferrite core or a choke...which is a ferrite inductor wound around a ferrite bead or core.

Also not all ferrite beads are the same. It depends on what is in the composition, how its mounted or how big it is. Some are designed to block a range of frequencies...some a narrow range....some are simply shifted to higher frequencies.

Here is a very simple explaination.
https://en.wikipedia.org/wiki/Ferrite_bead

They are generally cheap enough...that you could get a handful of different types and try them out on the wires to your headlights. But...I would check the transformer in the system first. Ray