Author Topic: Tail light wattage  (Read 1296 times)

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mirageags

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Tail light wattage
« on: March 17, 2015, 04:49:34 pm »
Does anyone know, or is there a way, to figure out the wattage of a stock 250x tail light? It uses 1/8 watt resistors and has 8 leds, does that make it 1 watt total?
Reason being i'm trying to figure out the draw it will use on my lighting system i'm building. If it uses 1 watt, thats fine, but if it uses alot more, then i'm gonna forget it
2017 KTM 250 EXC-F
1983 KTM 250 MXC
2005 Yamaha TTR 125L
2009 Suzuki Boulevard M50 (vz800)
2008 Honda TRX250EX ( wifes)
1988 yamaha razz 50 scooter

Jim Dettman

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Re: Tail light wattage
« Reply #1 on: March 17, 2015, 04:54:58 pm »

 1 watt it is.

Jim.
2009 CRF250x /2009 CRF450x

mirageags

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Re: Tail light wattage
« Reply #2 on: March 17, 2015, 04:57:58 pm »
Is that becuase of the 8x 1/8 resistors? Or was this godly info written somewhere? I have to be absolutely sure to calculate how long my battery setup goes with both lights
2017 KTM 250 EXC-F
1983 KTM 250 MXC
2005 Yamaha TTR 125L
2009 Suzuki Boulevard M50 (vz800)
2008 Honda TRX250EX ( wifes)
1988 yamaha razz 50 scooter

Jim Dettman

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Re: Tail light wattage
« Reply #3 on: March 17, 2015, 05:03:43 pm »

 Read it some where, but if it is 1/8 watt resisters in there, then the max would be 1 watt.   Anything about that and the resister would melt.   May be less then that though.

 You should be fine figuring 1 watt draw,  but if you really want to know exactly, I'll try and get a number for you.

Jim.
2009 CRF250x /2009 CRF450x

mirageags

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Re: Tail light wattage
« Reply #4 on: March 17, 2015, 05:14:18 pm »
I have been doing calculating to figure out the draw for the headlight, which will be 1.6 amps, the battery is a 5 amp hour, so i should be able to go up to 3 hours on the battery. I wanted to also incorporate the tail light as the license plate bracket actually bolts up through the bottom of it. And if it only draws a watt, why not have it.
2017 KTM 250 EXC-F
1983 KTM 250 MXC
2005 Yamaha TTR 125L
2009 Suzuki Boulevard M50 (vz800)
2008 Honda TRX250EX ( wifes)
1988 yamaha razz 50 scooter

Jim Dettman

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Re: Tail light wattage
« Reply #5 on: March 17, 2015, 06:21:09 pm »
I have been doing calculating to figure out the draw for the headlight, which will be 1.6 amps, the battery is a 5 amp hour, so i should be able to go up to 3 hours on the battery. I wanted to also incorporate the tail light as the license plate bracket actually bolts up through the bottom of it. And if it only draws a watt, why not have it.

  Formula is PIE: Power = Current * Voltage

  The stock headlamp on a CRF is 35 watts, so that would be 35/12 = 2.9 amps   

  BTW if you have a volt meter and can read the color banding on the resisters, then you can calculate how much the LED's in the tail light are drawing by measuring the voltage drop across the resister.   It's Power = Volts 1*Volts 2/Resistance.     So if you had 12 volts on one side, 11.8 on the other, and 500 ohms, it would be:  12 * 11.8/500  or .2832 watts.

 and yeah, I think a tail light would be well worth having from a safety stand point.



Jim.
2009 CRF250x /2009 CRF450x

redrider911

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Re: Tail light wattage
« Reply #6 on: March 17, 2015, 07:28:54 pm »
Mmmm pie. Or you can hook a meter up in series to your light and battery and get the amps and then convert to watts
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mirageags

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Re: Tail light wattage
« Reply #7 on: March 17, 2015, 07:32:03 pm »
I won't be using the stock bulb. It will be the cyclops 3600 lumen led. At 20 watts. Which will be 1.6 amps
2017 KTM 250 EXC-F
1983 KTM 250 MXC
2005 Yamaha TTR 125L
2009 Suzuki Boulevard M50 (vz800)
2008 Honda TRX250EX ( wifes)
1988 yamaha razz 50 scooter