The New And Improved Unofficial R65 Forum V2
General Category => Chit-Chat => Topic started by: azcycle on May 24, 2010, 06:53:55 PM
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I think I've settled on an aftermarket gauge I want to use on the r65, made by Acewell. (http://www.electrosport.com/street/speedometers-series-2700-2800.php)
I know keeping the charging light part of the system is vital, and I don't want to just remove it and replace with a resistor. The problem with the Acewell gauge is that the indicator lights are LED, which means that even though I could wire it up correctly, the LED won't pull enough to keep the charging system working.
I'm not much of an electrical expert, so I wonder: Could I install an in-line resistor to the charging/generator LED light and have it function correctly? Or would the resistor keep the LED from working altogether.
If that doesn't work, then I'll just have to wire a separate filament type bulb (thinking of using something small like this rom Radio Shack. http://www.radioshack.com/product/index.jsp?productId=2103779
Thoughts?
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i have nothing to add, except that I'm interested in following your experience with the acewell, since it's the brand/type I want to convert to.
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Cool. Keep us posted! I have noted the link. 8-)
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Anyone have any thoughts on whether a resistor placed inline on the generator LED would work? If you all don't think so, I'll just get the gauge model that doesn't have that light and just go with the radio shack option.
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LED's need a series current limiting resistor but the manufacturer of your unit will have taken care of that.
For the purpose of correct alternator operation you need a resistor in parallel with the led charge light/series resistor combination. I heard that 470 ohms is an appropriate value from someone who has actually done it. That calculates out to 0.4 watts so you will need a resistor with a minimum 0.5 watt rating. 1 watt would be better.
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I believe that you need a minimum of about 0.020 to 0.040 amps (20 to 40 milliamps) at initial switch on to drive the voltage regulator and energize the rotor sufficiently. Some LEDs are advertised as "12V" LEDs which have an integrated resistor inside them to limit the current, while a normal LED doesn't and requires that an appropriate external resistor be used depending on the voltage it will be subjected to. A typical non-integrated resistor red LED will have a voltaage drop of about 1.7V, a green LED about 2.2V You can assume 12V will be applied. Many small LEDs are rated for up to 20mA or 30mA of current, so you could make it work with appropriately rated discrete LED and say, a 470 ohm, 1/2Watt resistor or an integrated 12V LED as long as it will pass at least 20mA with 12V applied. It is entirely possible that the LED indicator on that unit has a series resistor already, but I didn't see any info to prove it or whether its connected "through" so that you could wire from it to the wire which goes down to the voltage regulator terminal.
I think something like that unit would look very cool inside a /5 headlamp shell!
I would contact the supplier for more info to determine if it would work directly or would need some external additions to ensure that the LED indicator on it worked with our wonderful Bosch charging system.
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Hmmm. It might be better to just order one without that LED and just use a Radio Shack filament mini-bulb that I can install myself. That way I know I can wire it in correctly. I'm probably going to have a friend fabricate some sort of mount so I can have the gauge, the ignition assembly and the mini-light all together.
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azcycle- really good thread on the acewell in the old's cool section over at adv.
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azcycle- really good thread on the acewell in the old's cool section over at adv.
Actually, I JUST found that thread over there! I thought I was original with this thread and look at that.... it's already been done! ;D