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Select the 21.5 Ohm resistor when going from a 10 watt incandescent turn signal to an LED turn signal."

https://www.revzilla.com/motorcycle...ors?query_id=2b62579e80581e0913872b936b9887a4

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As aTahmission shows, it depends on what size bulb you are replacing. The numbers he quotes are for a 12V system (14.3V nominal), and are for replacing a single bulb, so aren't what you will need. So, here's the math. Replacing one bulb of power W at a nominal Voltage V=7.1, you take V squared (= 50.4), and divide that by W to get Ohms. You do not want to connect that resistor at the flasher relay output, because it would be operating all the time; also, in represents one bulb, and you should have four. So connect that size resistor at each bulb housing, or divide the resistor Ohms value in half, double the Wattage, and connect one to each side.

In the quoted numbers, V=14.3, and the resistor replaces one bulb at 21W, so you get 204.5 / 21 = 9.7 Ohms; 9.8 Ohms, >21W is near enough. The 10W value is a bit off, too, but that's possibly the nearest available value in a 10W resistor, and is close enough.

Simpler would be a LED rated flasher relay, but they may not exist for a 6V system.

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Fantastic post!As aTahmission shows, it depends on what size bulb you are replacing. The numbers he quotes are for a 12V system (14V nominal), and are for replacing a single bulb, so aren't what you will need. So, here's the math. Replacing one bulb of power W at a nominal Voltage V=7, you take V squared = 49, and divide that by W to get Ohms. You do not want to connect that resistor at the flasher relay output, because it would be operating all the time; also, in represents one bulb, and you should have four. So connect that size resistor at each bulb housing, or divide the resistor Ohms value in half, double the Wattage, and connect one to each side.

In the quoted numbers, V=14, and the resistor replaces one bulb at 21W, so you get 196 / 21 = 9.8 Ohms, >21W. The 10W value is a bit off, but that's possibly the nearest available value in a 10W resistor, and is close enough.

Simpler would be a LED rated flasher relay, but they may not exist for a 6V system.

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I went back and made a few corrections. And, yes, I'm a retired electronics engineer, can you tell?:smiley_mornincoffeeFantastic post!

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Oh yes they do exist!Simpler would be a LED rated flasher relay, but they may not exist for a 6V system.

I have a LED electronic flasher in my Honda Trail 90 which is a 6 volt system.

It's been a long time, so I forget where I got it.

But keep looking around on the internet.

I assure you, you CAN get one!

EDIT!!! Here ya go! I found it!

Yamaha YSR-50 and Hot Rod 6-volt turn signal relay - LED and Standard

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Somehow, I could.I went back and made a few corrections. And, yes, I'm a retired electronics engineer, can you tell?:smiley_mornincoffee

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