BillB800si
S.E. MICHIGAN
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As some of you know much of the cheap Chinese import LED's give off RF Interference and interferes with radio/TV reception. A few years ago I ordered replacement trailer LED tail lights (complete lens & all)from Command Electronics. They worked great- very bright. Now I'm in the process of replacing many lights on my trailer with LED's so I contacted Command Electronics and asked them about their LED interference problems. Their reply was they addressed this situation and designed circuitry to eliminate it. just thought I would pass this along to those considering the same idea of replacements.
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Normk
Canada's Wet Coast
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A bit off topic but hopefully not a hijack.
Wanting to confirm an understanding of LED lights. I haven't noticed any RF from LED cells which have wired up for various purposes but have noticed RF from commercially produced lighting units and some flash lights. Maybe just haven't noticed RF because haven't specifically looked for the effect?
It is my understanding (and wish to confirm or learn) that the RF does not come from the LED cell itself but from electronic circuitry allied with the LED in order to control voltage, output, etc. Is this correct?
Also wondering if someone could outline the voltage/light output curve and voltage/life curve for a typical LED? Don't require fine detail, just an appreciation of the basic relationship.
I have been told that more light can be obtained by pulse-width modulating a higher voltage supply to an LED than by operating on a continuouspresumablysumeably at a lower voltage).
Not sure what one can do with this information but even scuriositycuriousity would be appreciated.
Just as with the charging systems designer lurking on another thread, am sure that there are some who know this subject in fine detail.
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vermilye
Oswego, NY, USA
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It is my understanding (and wish to confirm or learn) that the RF does not come from the LED cell itself but from electronic circuitry allied with the LED in order to control voltage, output, etc. Is this correct?
True. Not all replacement LED lamps contain VR circuits - those that do can be engineered so that they don't produce much RFI, but not all manufacturers bother.
I have been told that more light can be obtained by pulse-width modulating a higher voltage supply to an LED than by operating on a continuouspresumablysumeably at a lower voltage).
Also true, however poorly designed PWM will also cause RFI.
One solution is to purchase inexpensive non regulated LEDs directly from China. They are inexpensive enough that if they are damaged by over voltage, just throw them out & put a new one in the fixture. I've used these and haven't lost one yet...
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RoyB
King George, VA
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I had big time interference with COmmand Electronics and SUPER BIGHTS LEDs just a couple of years back. I strongly reccomnd you not blindly step-in and spend $150 to replace all your incandescent bulbs with any of those high dollar LED boards until you ordered just one or two and try them out.
The trouble was with the BUCK BOOST regulator they all used back then to allow their LED boards to operate with a 7v to 30VDC DC input range. The $4.99 cheap chinease board do not have the voltage regulator built into their boards so it isnt a problem. You may lose one every now and then but for $4.99 a board who cares... Just pop a new board back in...
I would be surprised to hear the big companies have found a cure for this problem...
My Posts are IMHO based on my experiences - PM/EMAIL me
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westend
all over
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Thanks for your input, Jon, I've been looking for an inexpensive solution to upgrade my interior lights and the ones you linked to seem cheap enough that I won't have to make my own. Heck, the adaptors are worth the price, IMO.
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westend
all over
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RoyB wrote:I had big time interference with COmmand Electronics and SUPER BIGHTS LEDs just a couple of years back. I strongly reccomnd you not blindly step-in and spend $150 to replace all your incandescent bulbs with any of those high dollar LED boards until you ordered just one or two and try them out.
The trouble was with the BUCK BOOST regulator they all used back then to allow their LED boards to operate with a 7v to 30VDC DC input range. The $4.99 cheap chinease board do not have the voltage regulator built into their boards so it isnt a problem. You may lose one every now and then but for $4.99 a board who cares... Just pop a new board back in...
I would be surprised to hear the big companies have found a cure for this problem... Good stuff, Roy! Your post brings a parallel question to mind: Would it be advantageous to install a voltage regulator at the source of power, i.e. at the converter output? This would allow for a good level of power to the other devices (not too concerned about LED lighting).
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RoyB
King George, VA
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The problem really isnt any noise regulation components problem that comes from the Converters. They are pretty clean... The problem is all of the various DC outputs the converter smart modes generate (12.6VDC, 13.2VDC, 13.6VDC, 14.4VDC, and sometimes 15.2VDC) These different levels of required DC outputs are necessary to fully re-charge batteries in a short period of time but will make the LED lights change brightness and maybe even blow a few strips of the LEDs that are in series to be able to run from a 12VDC source. I think the spec on the cheap china LED boards is a DC voltage range of 12VDC-14VDC so the 15VDC output of the COnverter migh blow a few LED segments which I think must be three LED in series for the 12VDC line. I have seen three LEDs go out on a board which probably means one out of the three has failed.
I dont think I would like the idea of adding a second heavy duty regulator circuit to maintain a certain DC VOLTS out for all of the trailer appliances while at the same time providing the BATTERy BANKS all of the various 12VDC levels to charge properly. I do however think the Marine world has such a second high power regulator to maintain a "set" 12VDC output. Just keep in mind the Converter still has to provide the different DC Voltage output levels to keep the batteries charged properly. This would be an expensive project to build-up a heavy duty regulator for the whole DC applinace 12VDC grid.
The best approach to me is what was started by the LED companies of having a individual LED board built-in regulator using a single cheap regulator chip but use a different approach that doesnt use the forced square wave BUCK BOOST approach. The same thing happens when you fire up an INVERTER. The switch frequency is much lower than the LEDs and really generates a loud BURRRRR noise in the 7Mhz bands real bad in my case. The LED regulators seems to only generate broad band noise in the VHF and UHF frequency bands. One post said he can also hear a white noise in his AM radio band receiver when he turns on his LED lights.
I was communicating with Mr Jason Weaver of BRIGHT LIGHTS LEDs a couple years back and they was experimenting with a different regulation approach called a LINEAR regulator for their LED boards in lieu of the BUCK BOOST Pulse Width Modulator regulator that was suppose to clear up the problem but never really heard back for any progress... Maybe they have solved the issue now... I ended up installing a cheap non-regulated china LED board as a quick PLAN B fix in one side of my dual light fixture and have a three way DC switch on it. I can turn on one side first that is using the non-regulated LED board with middle position OFF and the other position to turn on both sides of the DUAL LIGHT fixture at same time. So this gives me a quiet radio interference mode to use when camping off the power grid where it really hurt me the worse...
When I am hooked up at regular camp sites with hookups their TV signals are strong enought to override the regulated LED Boards and the cable TV usually works just fine. I still however have problems with the NOAH WX ALERT radio using its pull-up antenna and of course the Ham radio bands which use a roof mounted 5/8 wave length antenna still shows RFI signals across the vhf/uhf frequency bands.
At least I have a PLAN B in force at the moment and a work around situation when needed..
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ryanallie1
Magalia, Calif
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Hi All.
We have had a couple of different Brands of lED lights, that we have been using for several years now. The older ones we replaced with the 36 LED BA15's
bases. Replaced every light in our Motorhome with the LEDs in our Motorhome. We have never heard so much as anything form either brand of LED Lights. Our Motorhomes Radio is the OEM one. We have replaced both of the OEM CRT TV's, to LED TV's. None of them have ever picked any noises what so ever. Who knows, maybe we just got lucky. I really haven't seen this issues come up before, but that doesn't really say to much. Good Luck. Happy Travels. Dan & Jill
1998-33.5 Rexhall, Rexair SL. 460 EFI. F-53. HWH Levelers. 5.5G Gen. Convection/Microwave. 12 Cu Ft Side by Side. Water Purifier. Water Softner. 2 A/C's. Alarm Systems. 2 Honda EU2000i W/Kit. Toad CR-V W/SMI System. FMCA #F414397 Nam-Vet, 66-67-68,& 70-71
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RoyB
King George, VA
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I didnt notice my RFI interence either until I went camping without cable tv hookup. The first thing that happened was after I got my BATWING ANTENNA up and pointed to a HDTV signal from a nearby town I noticed everytime I turned on a LED light the HDTV picture would freeze and no sound. Then in just a minute or so after that it would blank the screen and say NO SIGNAL. Then if I turned the over head LED lights back off everything would jump back to life. This got me looking at everything else radio wise... I found the NOAH WX RADIO ALERT would lose its WX ALERT signal with the LED lights on. The Ham Radio and POLICE RADIO scanners would not pick up anything unless they were real strong signals... I probably had some wireless things not working as well like my Wireless Motion detectors on both sides of the trailer but I never checked those... My AM/FM radio worked just fine... Then I got on the HAM RADIO which has a built-in Signal-meter on it and the RFI coming from the LED lights was S-9 to +10 over S-9 all up and down the VHF and UHF frequencies in broad band signals with the LED lights on.
I didnt know I had the problem until I went looking for it. Of course after awhile I would have noticed I wasnt getting my usually chatter on the Police frequencies etc...
I hooked up to cable TV at home when we got back from the back in the woods trip and and the RFI from the LEDs was not as bad on the cable TV signals. After flipping through all of the channels I might have found one or two that blank off and come right back on ocassionally. As soon as I switched to the OTA BATWING antenna I could not pick up any of the normal NATL BROADCAST stations I usually get in my back yard until I turned off the ceiling LED lights. When I started asking others on here about what I was seeing I found out others were experiencing the same thing.
The bottom line in my case ended up being anything that uses a pull-up antenna like the NOAH WX ALERT RADIOs, or radio scanners using roof mounted antennas, or the crank up BATWING OTA antenna etc gets blanked out from the LED RFI signals. The radios that are in the VHF/UHF radio frequency bands were the only ones effected in my setup. The AM/FM Radio using its roof mounted antenna was not affected.
This was my situation at any rate when I first installed the COMMAND ELECTRONICS and LEDTRAILER LED lights. I also tried a couple of SUPERBRITES and other "good deal" brands with same problem. After spending all my monies I finally found out you had to use WARM WHITE LEDs to duplicate the original incandescant automotive bulb color and most LEDs had to put out around 450 LUMENS of light to be very useful to use in my applications. Then I also found out any LED assy that a built-in BUCK BOOST regulator chip on the LED boards that allowed you to use these LEDs boards from 11VDC to 30VDC would generated RFI signals... I eventually ended up with the $4.99 cheap China 36LED Boards that did not incorporate a built-in regulator chip which are still in use today.
My LED story haha...
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Almot
Vancouver
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vermilye wrote:
One solution is to purchase inexpensive non regulated LEDs directly from China. They are inexpensive enough that if they are damaged by over voltage, just throw them out & put a new one in the fixture. I've used these and haven't lost one yet...
"China boards" come in 16, 36, 48 and God knows how many other sizes (=number of LEDs). And input is always 12VDC. Is this possible without VR hidden somewhere? Not that I'm concerned about interference - Free to Air TV is hardly worth my outdoor time (at home in winter I watch it, though). Local FM radio reception is not affected much by interference, IMO.
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