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oprn Samba Member
Joined: November 13, 2016 Posts: 12730 Location: Western Canada
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Posted: Thu Jul 12, 2018 8:34 pm Post subject: Re: Buggy tail lights |
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Always something to learn! Spent the evening hooking up these new LED tail lights and the signal would not flash.
There was an "Aha!" moment when I realized it was a simple change of resistance in the loop problem. Measured a 1157 bulb - 118 ohms. Measured the new LED tail light - 1K ohm. Need less resistance so - tried a 340 ohm resister in parallel from the signal power wire to ground - slow blink. Next a 250 ohm resistor - about right for the blink speed.
Ohms law tells me that is a total value of 200 ohms not taking into account the resistance of the LED signal light the previous owner put on the front fender or the loop wiring resistance.
Good enough for an old Redneck! Now to solder it into the rear wiring harness and all will be good!
I suppose the other way to do it would have been to take the flasher apart and play with the capacitor values but this was easier!
You guys probably know all this stuff already! |
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Q-Dog Samba Member
Joined: April 05, 2010 Posts: 8700 Location: Sunset, Louisiana
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Posted: Fri Jul 13, 2018 5:12 am Post subject: Re: Buggy tail lights |
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Or, get a flasher made for LED bulbs. No soldering, just plug it in place of the old resistance type flasher. _________________ Brian
'69 Dune Buggy
'69 Beetle Convertible
'70 Beetle |
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Dale M. Samba Member
Joined: April 12, 2006 Posts: 20379 Location: Just a tiny bit west of Yosemite Valley
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Posted: Fri Jul 13, 2018 5:41 am Post subject: Re: Buggy tail lights |
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oprn wrote: |
Always something to learn! Spent the evening hooking up these new LED tail lights and the signal would not flash.
There was an "Aha!" moment when I realized it was a simple change of resistance in the loop problem. Measured a 1157 bulb - 118 ohms. Measured the new LED tail light - 1K ohm. Need less resistance so - tried a 340 ohm resister in parallel from the signal power wire to ground - slow blink. Next a 250 ohm resistor - about right for the blink speed.
Ohms law tells me that is a total value of 200 ohms not taking into account the resistance of the LED signal light the previous owner put on the front fender or the loop wiring resistance.
Good enough for an old Redneck! Now to solder it into the rear wiring harness and all will be good!
I suppose the other way to do it would have been to take the flasher apart and play with the capacitor values but this was easier!
You guys probably know all this stuff already! |
Here is one solution..
Another solution would be a different flasher, one designed to work with LEDS...
I have successfully used a TRIDON EL13 Flasher with LEDS, seems it needs minimally 0.180 Amps (180 milliamps) of current at 12 volts to operate properly during bench tests...
Dale _________________ “Fear The Government That Wants To Take Your Guns" - Thomas Jefferson.
"Kellison Sand Piper Roadster" For Street & Show.
"Joe Pody Sandrover" Buggy with 2180 for Autocross (Sold)
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All suggestions and advice are purely my own opinion. You are free to ignore them if you wish ... |
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oprn Samba Member
Joined: November 13, 2016 Posts: 12730 Location: Western Canada
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Posted: Fri Jul 13, 2018 7:41 pm Post subject: Re: Buggy tail lights |
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I am using the load resistor solution you mentioned Dale. With the resistance of my tail lights 250 ohms seems to work out just right for flash frequency. I put my meter on it and measured a peak of 24 mA which puts me pretty much at the maximum of my 1/4 Watt resistor. I let it run for a bit and the resistor was not getting warm to the touch at all so I think I will be ok.
6 ohm seems a little low for resistance but it so much depends on other components in the loop. 12 volts at 6 ohms would draw 2 amps which is quite a bit! With the 4 way flashers going that would be 4 amps and the stock VW fuse for the signal light curcuit is only 5 amps.
Maybe it's a misprint and should be 60 ohms. That would be more reasonable as the stock 1157 bulb is just over 100 ohms. |
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Dale M. Samba Member
Joined: April 12, 2006 Posts: 20379 Location: Just a tiny bit west of Yosemite Valley
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Posted: Sat Jul 14, 2018 7:37 am Post subject: Re: Buggy tail lights |
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oprn wrote: |
I am using the load resistor solution you mentioned Dale. With the resistance of my tail lights 250 ohms seems to work out just right for flash frequency. I put my meter on it and measured a peak of 24 mA which puts me pretty much at the maximum of my 1/4 Watt resistor. I let it run for a bit and the resistor was not getting warm to the touch at all so I think I will be ok.
6 ohm seems a little low for resistance but it so much depends on other components in the loop. 12 volts at 6 ohms would draw 2 amps which is quite a bit! With the 4 way flashers going that would be 4 amps and the stock VW fuse for the signal light curcuit is only 5 amps.
Maybe it's a misprint and should be 60 ohms. That would be more reasonable as the stock 1157 bulb is just over 100 ohms. |
At a bench test a 1157 bulb does draw about 2 amps (actual) so basically if you are flashing two incandescent bulbs you flasher need to be able to handle about 4 amps (per side), this where thermal flashers work the best (flash rate) with LEDS I prefer flash rate determined by flasher electronics and not amperage loads...
Dale _________________ “Fear The Government That Wants To Take Your Guns" - Thomas Jefferson.
"Kellison Sand Piper Roadster" For Street & Show.
"Joe Pody Sandrover" Buggy with 2180 for Autocross (Sold)
============================================================
All suggestions and advice are purely my own opinion. You are free to ignore them if you wish ... |
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oprn Samba Member
Joined: November 13, 2016 Posts: 12730 Location: Western Canada
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Posted: Sat Jul 14, 2018 9:07 am Post subject: Re: Buggy tail lights |
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Sure. |
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tgodber Samba Member
Joined: May 02, 2004 Posts: 410 Location: Okanagan Falls B.C. Canada
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Posted: Sat Jul 14, 2018 10:55 am Post subject: Re: Buggy tail lights |
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All my lights are LEDs. Bought this flasher. End of problem. I have it in two buggies.
Friend went to an Auto Supply store and bought a flasher that they assured him would work. Did not work. They would not take it back. He was out $30.
I said quit screwing around and buy this flasher. It works every time.
_________________ My wife said I never listen to her.
Or something like that! |
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EVfun Samba Member
Joined: April 01, 2012 Posts: 5481 Location: Seattle
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Posted: Sat Jul 14, 2018 11:06 am Post subject: Re: Buggy tail lights |
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oprn wrote: |
I am using the load resistor solution you mentioned Dale. With the resistance of my tail lights 250 ohms seems to work out just right for flash frequency. I put my meter on it and measured a peak of 24 mA which puts me pretty much at the maximum of my 1/4 Watt resistor. I let it run for a bit and the resistor was not getting warm to the touch at all so I think I will be ok.
6 ohm seems a little low for resistance but it so much depends on other components in the loop. 12 volts at 6 ohms would draw 2 amps which is quite a bit! With the 4 way flashers going that would be 4 amps and the stock VW fuse for the signal light curcuit is only 5 amps.
Maybe it's a misprint and should be 60 ohms. That would be more reasonable as the stock 1157 bulb is just over 100 ohms. |
How many watts is the incandescent brake light? Watts equals volts times amps. The typical 1157 has a 20 watt brake light function, so it draws about 1-2/3 amps. In the car it typically runs closer to 13 volts so it will draw a little less current (the resistance of Tungsten increases the hotter it gets.)
Typically, you can use a 10 ohm resistor to make the old thermal flashers work because the LEDs still draw some current. A single 1157 brake light filament is about 8 ohms.
I have a 21 watt, 6 volt, 3rd brake light on the bumper of my old Bug. That is only about 2 ohms of resistance! _________________
Wildthings wrote: |
As a general rule, cheap parts are the most expensive parts you can buy. |
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tgodber Samba Member
Joined: May 02, 2004 Posts: 410 Location: Okanagan Falls B.C. Canada
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Posted: Sat Jul 14, 2018 11:08 am Post subject: Re: Buggy tail lights |
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My tail lights. LEDs in a stainless steel cup.
_________________ My wife said I never listen to her.
Or something like that! |
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oprn Samba Member
Joined: November 13, 2016 Posts: 12730 Location: Western Canada
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Posted: Sat Jul 14, 2018 12:32 pm Post subject: Re: Buggy tail lights |
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tgodber wrote: |
I said quit screwing around and buy this flasher. It works every time.
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The new flasher is most likely the best option as the load resistor way I discovered changes flash speed with changing battery voltage. Not a big deal but a solid state timer type would not do that I suspect. |
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oprn Samba Member
Joined: November 13, 2016 Posts: 12730 Location: Western Canada
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Posted: Sat Jul 14, 2018 8:24 pm Post subject: Re: Buggy tail lights |
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All in place and just missing one pigtail to have them all working. Still not a bikini quality view but I am liking it better than the original. And the visability is WAY better!
old ones
new and improved version
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