 smegballs World Chat Champion
Joined: 28 Oct 2007 Karma :  
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 Posted: 18:30 - 10 Apr 2014 Post subject: DIY LED indicators |
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Well I fancied easing the electrical load on my bike somewhat, as I'm thinking of beefing up the headlight, something easy to start with.... led indicators rather than the stock 21W bulbs!
As I'm going travelling with the bike later in the year, I want to keep everything compatible with the standard bulbs, in case I have problems and need to what a normal incandescent replacement in at some point.
I came up with the following:
Indie bulb + resistors + solder + poundshop bike light = Led indie bulb.
https://i.imgur.com/qsBfbbg.png
Fag packet calculation said that about 75 ohms of resistance was needed*, so thats two 150R resistors in parallel.
Crunched out all the glass and melted through the solder pip and soldered the resistor leg in the hole, the cap is soldered to one of the led negative pins. Pretty impressed with the result considering it only cost a quid each, normally you can expect to pay 5/6 quid for each led bulb!
*for anyone interested.
5 white leds in parallel - about 3.5V forward drop for a white led and probably need about 30mA each.
Total current = 5*0.03A = 0.15A
Assume supply voltage of 14V (engine running and charging)
Resistance = Voltage / Current
Resistance = (14 - 3.5) / 0.15
Resistance = 70 ohms |
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 moonzoomer World Chat Champion
Joined: 01 Jul 2012 Karma :   
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 Posted: 19:21 - 10 Apr 2014 Post subject: |
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