LED died after a few weeks.... WTF

My 50+ year old farm tractor had no indicator lamp to indicate the ignition power is on. There is no key, just a push-pull switch. There is also no gas gauge, so I never know when it will run out of gas. It's no big deal to run out of gas. I just need to make sure I keep a 5 gallon can on hand. The problem is that when it runs out of gas, I often forget to shut off the ignition switch, and if that switch stays on for a few hours, the battery is dead.

I went to Radio Shack and bought a LED "pilot light" (has a built in resistor and an enclosure around it). It's made for 12 volt. (The tractor has a 12v battery). I installed it, and it worked great. Within a few weeks I noticed it would flicker, get dim, go back to normal, and so on. Eventually is just died, after only a few weeks of use. Yea, the wiring is fine. I intentionally chose a LED to avoid changing burned out bulbs.

Why would a LED burn out so quickly?

I should mention that the tractor has an alternator from a modern car, with built in regulator. These tractors originally had an old generator with eternal regulator, and were 6 volts. Almost everyone who still uses them have converted them to 12v, which is simply changing to a modern alternator, getting a 12v starter, changing 2 headlight bulbs, and putting a different resistor on the ignition coil. And of course using a 12v car battery.

Maybe this is just the result of buying crap from Radio Shack.... But I wonder if the vibration of the tractor or something else caused such a short life???

Reply to
tangerine3
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Water. Tractors don't tend to be dry. Cheap electronics from radio shack don't tend to resist water. Or else your mouse (every tractor dashboard has at least one, in my experience) likes the flavor of the wire - if so, that will become obvious when you remove it.

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Reply to
Ecnerwal

sometimes, stuff just fails. Split the resistor in two and put a zener from the middle to ground. Mount the led so that the leads can't move wrt the head under vibration.

Reply to
mike

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What kind of Tractor? (I love my ~'49 T0-20 Fergeson.) I like the water/ wildlife idea, maybe you can go to the local tractor dealership and get an indicator lamp made for outdoor use.

I check all the fluid levels before starting the tractor, so I rarely run out of gas. It's also got a fuel valve that you can open another two turns and tap an extra gallon of gas in the bottom of the tank.... So you don't have a long walk to the back forty.

George H.

Reply to
George Herold

On a sunny day (Tue, 29 May 2012 18:33:47 -0500) it happened snipped-for-privacy@toyotamail.com wrote in :

Vibration? I killed an expensive blue LED by simply bending the wires a few times too many. wires did not break, but internally something came lose in the LED. Weak plastic. That would explain why it started to flicker first.

Reply to
Jan Panteltje

A Farmall Super M. I like the Farmalls. I have an H too, but its presently needing major repairs.

These Farmalls have a small box on the steering post for switches, a fuse holder, and stuff like that. I put the LED in there. While I'm sure a little moisture gets in there, it's pretty water tight, and mice can not get inside. The external wiring is exposed and nothing chewed on that. But I'll have to see what the dealership has, since this didn't work.

If I'm going out to the field, I do check the gas, but most of the time I'm just running hay bales and other feed from the hayshed to the barns and paddocks. 10 or more square bales get fed each and every day in all climates and weather conditions. In good weather I might use the garden tractor with cart, but most of the time the Farmall loader is the fastest and easiest. Often the weather is crappy, so it's just toss the bales on the loader and go. I usually dump in 5 gallons at a time, so I sort of know about what day I'll run out, unless I do other chores with the tractor in between. My gas can is normally within 300 feet when I'm doing chores. The problem is that I may run out of gas just as I'm finishing, and my last hay goes downhill, so I can coast down. I've been known to toss a few bales on the hood of my car too if I'm in a hurry and run out of gas. But at my age, I'm forgetful, and just never seem to remember to shut off the switch when I run out of gas. When that LED was working, I always saw it. Bright Yellow one!!!

Maybe I'm wrong, but it would seem to me that the dealerships would have all incandescent bulb type indicator lights. I wanted LED to eliminate replacing bulbs and even more to eliminate a power sucking incandescent bulb. LEDs use almost nothing....

Reply to
tangerine3

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Fun! Here's a scan of my Ferg, with the boy on top. (~ 10 years ago.)

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All my 'farm' vehicles are in various states of repair. Mostly fixed enough to just get the job done. (I wish I had more time.) That's why I always have to check fluid levels... There's always a chance the water, oil or hydralics developed another leak.

George H.

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Reply to
George Herold

Possibly because the alternator charging the battery has a fair bit more than 12v across the terminals (maybe 16-17v peak). I am surprised that it is enough to shorten the LED lifetime but with junk from RadioShack anything is possible. Try again and be careful not to bend the leads close to the LED plastic - that will kill them.

I'd bet on mechanical handling whilst installing it.

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Regards,
Martin Brown
Reply to
Martin Brown

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Cheap LED won't last long as you expect...

In theory vibration is not the cause, over current is most likely

btw, how you know the LED died, or just a bad continuity in the circuit ?

Reply to
halong

my guess would be he has it connected to the solenoid circuit for the fuel or ignition, either way, both the same. If no wheeling protect or over voltage is employed, this little device will be short lived!

Of course, over current I(f) does not help either. And If memory servers, direct sun light on the dome of the LED can play havoc. Being farm equipment, it most likely is exposed to the sun a lot.

Jamie

Reply to
Jamie

Never known an indicator LED killed by solar exposure. The ancient ones were too dim to see in strong sunlight but that is a different matter.

It crossed my mind after I had posted that the starter motor back emf probably exceeds the reverse bias to kill an LED not protected by a diode. Tractors are very harsh environments so the poor LED will require a bit more protection than just a series resistor. Inductor in series and diode in parallel should tame the electrical environment.

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Regards,
Martin Brown
Reply to
Martin Brown

Electrical spikes. The ignition system delivers HUGE spikes on the primary side, that's why they have "condensers" in the old breaker ignition, to prevent burning the points away with the arcing. Even electronic ignition generates massive spikes, but the electronics is built to handle it. When you turn the key off, the ignition system has no place to send those spikes (like into the battery) but the poor LED. You need to provide a spike clipping circuit to protect the LED.Possibly it only needs to be protected from negative spikes, so a simple diode across the LED that will conduct when the polarity is reversed might solve it.

Jon

Reply to
Jon Elson

This is NOT a bare LED. It's in a holder with insulated wires coming out. All I did was drill home in tractor switch box, insert and tighten the nut. Connected the ground wire to the frame, red lead to the wire screw on the ignition switch. I made pigtails (since the LED wires were short), put spade terminals on their ends to connect to the ign switch and ground. Used very small wirenuts to connect the LED wires to the pigtails. (I do have a ground wire from the battery terminal to this control box to insure a good ground, since this tractor is old, there is some rust where things are bolted, so this makes a good ground)

[The built in resistor is inside the light]

This is the exact light that I have. On the Radio Shack website. Orange (looked yellow to me, but color was good when it worked).

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Reply to
tangerine3

You might look closely at the resistor inside the housing. It may not be =

soldered properly or vibration may have caused it to break a lead on the =

LED. It does not appear to be potted or secured in any way. The = flickering=20 sounds like a loose connection.

Here is an LED display that snaps into a 1/2" hole, and it may be of = higher=20 quality, for about the same price:

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6T5470 or this for $1.39
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Yellow is much more common than orange. And here is one for $0.79:

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/17304+LE/

I realize it's easier to go to your local Radio Shack, and they should = have=20 what you need. But their quality and selection are not very good. You = might=20 also check an auto supply store for indicators meant for automotive use.

Paul=20

Reply to
P E Schoen

Well I don't know if solar exposure is killed your LED as in it not being Photalic any more? It could be. An LED does behave like a photo detector. It is sensitive to light, as well as it being able to emit it.

The case is domed and it's like a magnifier glass. On top of that, heat can distort the case, causing deformation of the leads in side. That is my take on it.

Just get a couple of zener diodes. I think they still come two in a package from the shack. Put them back to back in series and put that network across the leads of a good LED. a couple of the 5..6 volt types should work and I think the shack as those, two in a package.

Jamie

Reply to
Jamie

try adding a series resistor of about 100 ohms in the positive lead and a zener diode at the junction of the new resistor and the LED bulb enclosure (you will need a new one of them too.) The end of the zener without the stripe should be conected directly to the black lead on the LED enclosure. These parts will help

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We have failed to address the fundamental truth that endless growth is  
impossible in a finite world.
Reply to
David Eather

That's a nice looking tractor. I've seen lots of Internationals, John Deere, and Fords, along with some of the lesser known types such as Alice Chalmers, Minneapolis Moline, Cockshutt, and a couple others, but your's is the first Fergeson I've seen.

Thanks for the photo.

My Farmall Super M is very dependable. Starter drives are my biggest problem, and the brakes are always needing some attention. Other than that, I just need to change the oil, add gas, and make sure to grease all the fittings regularly. And of course replace tires that cost more than the tractor did.

Besides re-painting mine. I replaced all the old wiring with new wire, that old cloth stuff was in poor shape. I also had to shim the steering gears, or I'd have to turn the steering wheel 3 inches before the tires would move (typical on all the Farmalls, just as the brake issues and starter drives).

Reply to
tangerine3

The problem has been identified elsewhere in the thread. Your LED is almost certainly being killed by the back EMF from the inductive load of either the starter motor or spark coil. You need a second resistor in series and a diode in parallel to prevent the reverse voltage of the LED being exceeded by voltage spikes from the ignition/starter motor.

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Regards,
Martin Brown
Reply to
Martin Brown

The TO20,30 are very much like the Ford 2N, 9N tractors of the same vintage. There=92s a Masey-Fergeson dealership up the road from me. They must have sold a lot of them in their day, because I see them all around where I live. I got the tractor for ~$700, but it had water in the oil and I had to rebuild part of the engine block and piston sleeves before I used it. (Much to the chagrin of my wife, as the tractor spent its first few months in pieces in our garage.) Since then I=92ve had the head rebuilt and last year the hydraulic pump. It=92s always something. I=92ve yet to put new tires on it. It doesn=92t get much work, mostly just dragging a mower deck around the yard and trails.

George H.

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Reply to
George Herold

"David Eather" wrote in news:op.we5nyxjewei6gd@phenom-59fddf15:

perhaps inductive spikes(reverse spikes?) from the starter or other electrical devices damaged the LED. they might easily exceed the LED's voltage ratings.

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Jim Yanik
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Reply to
Jim Yanik

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