Hot bodies undertail dim led's

[damannz]

Man the led lights on my undertail are dim.I just installed it today and it has the directionals and the brake light in the same round light casing.Anyone else have this problem ? if so how did you fix it?I know its only a matter of time before the MAN breaks my ballz over it. Thanks alot

[Stoneman]

Hmmmmm....gotta think about it for a few. I wish you had said something about installing an undertail. I've done it, and'll NEVER do it again. It looks great, but there's ALWAYS problems associated with such mods. And there'll ALWAYS be something with shit like that. It's never ending...

[bigred875]

how old is the blinker fluid? You may need to change that...

[damannz]

Awesome..... completely forgot about the blinker fluid!!! But i was thinking that maybe some other led's might fit in the housing and wanted to see if anyone had changed thiers before and could suggest where to get some from besides ebay. I dont want to get run into either because i can already see that people are having a hard time seeing them.........thanks

[Honclfibr]

The brightness of LEDs will be determined by the amount of current flowing through them. This is a strange concept to most amateur electrical hobbyists but it's the nature of semiconductors.

The current flowing through an LED is normally set by use of a "current limiting resistor". If you know the value of this resistor, and the maximum steady state current that the LED can handle, you can adjust the current through the circuit using this formula:

Current through circuit = (Supply Voltage - LED Voltage Drop) / Resistor Value.

Figure 13.8V for the supply voltage and 1.8V for an average red LED but who knows if it's a standard LED there's a million colored and high brightness LEDs all with different diode drops. IF you can find the current limiting resistors you can measure them and drop their values a bit at a time until you achieve your desired brightness or your LEDs burn out

Another thing to watch for, the resistance from the battery to the LED will add with the resistance of the current limiting resistor, so in theory long runs with small gauge cable, poorly made or too many connections/junctions, all those things can increase the resistance in your circuit and therefore decrease the brightness of your LED. In practice, unless you did an incredibly shitty wiring job like twining your wires together with your fingers and wrapping them in electrical tape, typical current limiting resistors are several hundred ohms, while your line drop should be well under a few ohms or you've got serious problems.

[Rice-rocket1]

The LED's in the undertail for Double"D"s ZX-10R are very hard to see during the day but are easily seen at night. Take a look at them in the dark and I bet you'll see a difference....


OFF


ON

[dhuze]

Originally posted by Honclfibr
The brightness of LEDs will be determined by the amount of current flowing through them. This is a strange concept to most amateur electrical hobbyists but it's the nature of semiconductors.

The current flowing through an LED is normally set by use of a "current limiting resistor". If you know the value of this resistor, and the maximum steady state current that the LED can handle, you can adjust the current through the circuit using this formula:

Current through circuit = (Supply Voltage - LED Voltage Drop) / Resistor Value.

Figure 13.8V for the supply voltage and 1.8V for an average red LED but who knows if it's a standard LED there's a million colored and high brightness LEDs all with different diode drops. IF you can find the current limiting resistors you can measure them and drop their values a bit at a time until you achieve your desired brightness or your LEDs burn out

Another thing to watch for, the resistance from the battery to the LED will add with the resistance of the current limiting resistor, so in theory long runs with small gauge cable, poorly made or too many connections/junctions, all those things can increase the resistance in your circuit and therefore decrease the brightness of your LED. In practice, unless you did an incredibly shitty wiring job like twining your wires together with your fingers and wrapping them in electrical tape, typical current limiting resistors are several hundred ohms, while your line drop should be well under a few ohms or you've got serious problems.

What the Hell did you just say?

[Degsy]

Originally posted by Honclfibr
The brightness of LEDs will be determined by the amount of current flowing through them. This is a strange concept to most amateur electrical hobbyists but it's the nature of semiconductors.

The current flowing through an LED is normally set by use of a "current limiting resistor". If you know the value of this resistor, and the maximum steady state current that the LED can handle, you can adjust the current through the circuit using this formula:

Current through circuit = (Supply Voltage - LED Voltage Drop) / Resistor Value.

Figure 13.8V for the supply voltage and 1.8V for an average red LED but who knows if it's a standard LED there's a million colored and high brightness LEDs all with different diode drops. IF you can find the current limiting resistors you can measure them and drop their values a bit at a time until you achieve your desired brightness or your LEDs burn out

Another thing to watch for, the resistance from the battery to the LED will add with the resistance of the current limiting resistor, so in theory long runs with small gauge cable, poorly made or too many connections/junctions, all those things can increase the resistance in your circuit and therefore decrease the brightness of your LED. In practice, unless you did an incredibly shitty wiring job like twining your wires together with your fingers and wrapping them in electrical tape, typical current limiting resistors are several hundred ohms, while your line drop should be well under a few ohms or you've got serious problems.

Great, now i've got brain all over my keyboard. Thanks.

[damannz]

yep my lights are just like that in the day time rice rocket....................just came in from checking them in the dark and they are pretty bright.Maybe i just thought they should be brighter than they were because i seen a friends on his gsxr and they were super bright even in the day time which is mostly when i ride because i have to look after the little one. honclfibr thanks for the run down on how the led functions ..

[legalspeed]

Originally posted by Honclfibr
The brightness of LEDs will be determined by the amount of current flowing through them. This is a strange concept to most amateur electrical hobbyists but it's the nature of semiconductors.

The current flowing through an LED is normally set by use of a "current limiting resistor". If you know the value of this resistor, and the maximum steady state current that the LED can handle, you can adjust the current through the circuit using this formula:

Current through circuit = (Supply Voltage - LED Voltage Drop) / Resistor Value.

Figure 13.8V for the supply voltage and 1.8V for an average red LED but who knows if it's a standard LED there's a million colored and high brightness LEDs all with different diode drops. IF you can find the current limiting resistors you can measure them and drop their values a bit at a time until you achieve your desired brightness or your LEDs burn out

Another thing to watch for, the resistance from the battery to the LED will add with the resistance of the current limiting resistor, so in theory long runs with small gauge cable, poorly made or too many connections/junctions, all those things can increase the resistance in your circuit and therefore decrease the brightness of your LED. In practice, unless you did an incredibly shitty wiring job like twining your wires together with your fingers and wrapping them in electrical tape, typical current limiting resistors are several hundred ohms, while your line drop should be well under a few ohms or you've got serious problems.

Buy a smaller resistor (less resistance) and wire it properly. Check the specs on the LED so you don't fry it.

[ZX-12R]

To get the maximum brightness out of an LED, a current limiting resistor doesn't cut it. LEDs can be safely driven by pulses of current much higher than their normal rating. The high current makes the LED much brighter. Pulse it fast enough and persistence in the eye makes it appear that it is on constantly. There is usually a feedback loop that allows the pulse generator to maintain a constant current regardless of battery and charging system performance. A good undertail will have this setup and it is not hard at all to design and build the circuit that accomplishes it but it is much harder than simply connecting a resistor in series with the LED.

Anyway, if you want to keep your current setup but experiment with the brightest LEDs on the market, check out http://www.lumileds.com . In their product line, the Luxeon III is probably the brightest LED that is commercially available. I have used their regular Luxeons (1/3 as bright) and they are intense to say the least. They are very easy to see in direct sunlight.