Beware of possible issues when installing some LED lights on your tractor

[k0ua]

I have a 2M SSB rig, and made contact to Florida with an S3 from new york!. I'm sure 6M is even better, but don't have 6M gear. SSB is the way to go, though!..

48 states and 26 countries confirmed so far on 6 meters. Best DX was Japan in 2018 from my location in Branson, Mo. 100 watts to a 2 element Moxon at 45 feet. I don't know if I will live long enough to see F2 propagation again on 6 meters or not. I have never actually seen any as I haven't been on 6 long enough to have seen it. But Meteor Scatter, TEP, and Sporadic E, make for some interesting happenings. And what ever it is in the spring that allows North America to work Japan. I still don't know what that is for sure. But the MUF has never risen to 50Mhz in the time I have been on.

 

[W8BYA]

I wanted to provide a quick update on the LED RFI issue. As you may recall I ordered a commercial AC powerline filter since it was quickly available and not very expensive (about $12 delivered). I knew it would not be my 1st choice but I figured what the heck, let's try it for fun. I made some measurements of this filter today using the trouble-maker LED assm and the results were quite disappointing.

Down at low frequencies, below 30 MHz, there was an honest 10-20 dB drop of conducted RFI but above that the RFI attenuation was marginal at best. Therefore I do not recommend this filter as a possible solution.

I understand this was an AC powerline filter but in fact it's topology (design philosophy) is very similar to a prototype filter I whipped together in about an hour using whatever parts were scattered about on the work bench. It turns out the 2 filters were very similar in their make-up with the major difference being the values of the parts used in both filters. Truth be told, in looking at the values of the large inductors and capacitors it is not surprising that I did not see more attenuation at the higher frequencies.

I have enclosed a picture of the commercial and prototype filters. Normally I would not display my sloppy thrown together prototype to the world but I did want you to see what it did look like component & size wise. There are also a couple small capacitors underneath the circuit board.

As a final confirmation I replaced the commercial filter with my "ugly-duckling" prototype and all of the RFI was pretty much knocked down to the ground. So, until I find a suitable commercial filter (one suited better for lots of attenuation across a very broad-range of frequencies) your choices are to DIY (build your own like I did) or use a different, less noisy LED light fixture. If I do find a suitable commercial unit I will make sure I post the make/model number etc.

 

[k0ua]

Proof positive that if you want something done right you have to do it yourself?

I understand your thoughts though, It would be a lot easier to just take an off the shelf component for a good price to solve the problem. But life sometimes isn't very nice.

 

[Threepoint]

Thanks for the update, and for all your efforts!

 

[Argonne]

I appreciate your comments & input but IMO we are veering off course from the direction I want to go.

You be the judge, W8BYA, but I propose to push this further off in an entirely different direction...lol, but it IS related to LED lighting on tractors.

My Terramite T7 came with an amber beacon on the roof. The original (strobe based, talk about RFI) died, and I decided to replace it with one of the cheap, LED based offerings. Long story short, I went through 3, made by 2 manufacturers. All of them died within the first few hours of use. The failure mode was the destruction of the driver chip. After the second one, I measured ambient and running voltages on the machine, and all was nominal. Tops was about 13.9VDC running with a fully charged battery. I figured I had settled on a poorly designed unit that couldn't handle a high duty cycle in the Texas heat, and recently got a unit from Tractor Supply that is a re-design of an un-impressive one they sold a few years ago. I installed it, and it worked great till the second time I started the machine, and now it's dead. If I take it apart I am expecting to find another cratered driver.

The light bulb (the one in my head) finally went on. I am probably looking at starting motor generated transients, and I need to install something on the B+ line, or in line with the strobe to protect it from such events. I am currently deciding what specifically to use. I don't have a number for a suitable MOV or module or coil, and I'm wondering if anything comes to mind for the purpose. The strobe is wired to go on with the ignition, and I want to keep it that way (i.e., no switch).

I love my Terramite, but they sure don't have any parts installed in them that are not absolutely necessary, and apparently, some kind of electrical system surge suppressor is on that list. Now that I think about it, I don't even know if cars have a discreet component that fulfills that mission. Anybody have any ideas?

 

[k0ua]

You be the judge, W8BYA, but I propose to push this further off in an entirely different direction...lol, but it IS related to LED lighting on tractors.

My Terramite T7 came with an amber beacon on the roof. The original (strobe based, talk about RFI) died, and I decided to replace it with one of the cheap, LED based offerings. Long story short, I went through 3, made by 2 manufacturers. All of them died within the first few hours of use. The failure mode was the destruction of the driver chip. After the second one, I measured ambient and running voltages on the machine, and all was nominal. Tops was about 13.9VDC running with a fully charged battery. I figured I had settled on a poorly designed unit that couldn't handle a high duty cycle in the Texas heat, and recently got a unit from Tractor Supply that is a re-design of an un-impressive one they sold a few years ago. I installed it, and it worked great till the second time I started the machine, and now it's dead. If I take it apart I am expecting to find another cratered driver.

The light bulb (the one in my head) finally went on. I am probably looking at starting motor generated transients, and I need to install something on the B+ line, or in line with the strobe to protect it from such events. I am currently deciding what specifically to use. I don't have a number for a suitable MOV or module or coil, and I'm wondering if anything comes to mind for the purpose. The strobe is wired to go on with the ignition, and I want to keep it that way (i.e., no switch).

I love my Terramite, but they sure don't have any parts installed in them that are not absolutely necessary, and apparently, some kind of electrical system surge suppressor is on that list. Now that I think about it, I don't even know if cars have a discreet component that fulfills that mission. Anybody have any ideas?

I wonder if a zener as a clamping diode would help. It would interesting to have a storage scope across your power line during starting would show. But I bet you are on the right track with the back EMF out of the starter solenoid maybe?

 

[Argonne]

I wonder if a zener as a clamping diode would help. It would interesting to have a storage scope across your power line during starting would show. But I bet you are on the right track with the back EMF out of the starter solenoid maybe?

I altered my search terms a bit and found DC-DC converters for a palatable price. I'm going to give this a shot for driving my device. RFI isn't an issue in my application, so I ain't skeered. https://www.amazon.com/Converter-12...60ZC8JDFHZD&psc=1&refRID=9WZXJQFNB60ZC8JDFHZD

 

[k0ua]

I altered my search terms a bit and found DC-DC converters for a palatable price. I'm going to give this a shot for driving my device. RFI isn't an issue in my application, so I ain't skeered. https://www.amazon.com/Converter-12...60ZC8JDFHZD&psc=1&refRID=9WZXJQFNB60ZC8JDFHZD

Well if the starter transients fry your DC-DC converter... you will know..

Heck maybe just a good silicon diode between Positive and negative at the input of the lights with the cathode (banded end) towards Positive. A 1N4007 comes to mind.

Might fix it, might not.

https://www.amazon.com/MIC-Silastic...4?keywords=1n4007+diode&qid=1574543124&sr=8-4

 

[radios1]

Well if the starter transients fry your DC-DC converter... you will know..

Heck maybe just a good silicon diode between Positive and negative at the input of the lights with the cathode (banded end) towards Positive. A 1N4007 comes to mind.

Might fix it, might not.

https://www.amazon.com/MIC-Silastic...4?keywords=1n4007+diode&qid=1574543124&sr=8-4

a bidirectional Transorb is much better.. or an MOV.

 

[Argonne]

a bidirectional Transorb is much better.. or an MOV.

I was looking at MOVs, but I got bogged down in specs that I didn't remember the explanation for. One was a 15VDC MOV rated at 1000Amps. That sounded promising, but there was also a "Clamping Voltage" spec rated at 48VDC. Spent a little time trying to find what "clamping voltage" was to an MOV, but finally decided I was going to spend more time/money researching in order to save a few bucks on an "elegant" solution than it was worth. I don't have a scope anymore, so my scientific analysis options are few.