Idiot Light Replacement

[Kiwi_Roy]

I installed LEDs to replace the Incandescent lamps in my V11 Sport. I had a few problems which I will list below in the hopes that others will benefit.

I ordered 74-R lamps from SuperBrightLEDs , 1 Blue, 2 Green, 3 Red $1.19ea.

http://www.superbrightleds.com/cgi-bin/sto...mini-wedge.html

1) First of all I tried a direct replacement without success. The bases look similar but on close examination the LED contact wire is wrapped around the end of the base and bent back so it makes contact on both sides (see print) shorting out the lampholder. I tried clipping one side off the wire, this works but not well as it's a little tricky getting it into the base. Since the LEDs are long lasting I decided to remove the contacts and solder the lamps in place. The rubber base comes out quite easy with a bit of tugging and the new lamps fit snugly.

2) Because the wires have oxidized over the years I had dificulty getting a good solder joint so I clipped the brass contact off leaving the crimp part which is much easier to solder too. Once the wires were connected the lamp slipped back into the rubber base.

3) Unlike incandescent lamps LEDs are uni directional (diode) so you need to make sure they are connected up with the right polarity by turning on the ignition and touching the lamp to the wires.

Current in the flasher circuit indicator lamp flows in both directions from the active side to the non active side so it needs some additional components. I added a bridge rectifier from Radio Shack. A couple of diodes will also work if the negative side of the lamp is connected to the chassis (see print).

4) My V11 Sport has a thermistor type low fuel sensor, this draws about 20 mA with the tank full. The heat this produces is carried away by the fuel. When the fuel is low the thermistor is no longer kept cool so it heats up, the resistance drops, the current goes up some more until it draws enough current to light the incandescent lamp. Unfortunately the 20 mA the lamp thermistor draws turns on the LED as it only requires 10 mA for full brightness. The solution is to add some additional load in parallel with the LED. I could have used fixed resistors but one of the old lamps in parallel does a better job.

If your bike has one of the reed type level switches the additional load will not be required.

 

In hind sight I should have ordered 6 new lampholders from SuperBright to replace the Guzzi ones. These would have saved me some work and they wouldn't short out like the Guzzi originals. I don't see a suitable holder on their website but I'm sure they have one. (the T10S-SP is too large)

The colour of new LEDs should match the colour of the lenz otherwise they will look dull.

If you have trouble pulling the old glass lamps, pull the rubber base out or a slide piece of plastic tubing over the lamp so that long nose pliers will get a better grip.

 

Although it took me about 3 hours I am very pleased with the results. The LEDs are more visible in bright sunlight.

 

While I was at it I added an LEDs to the N/O contact of each relay, but that's another story.

 

Have Fun

Roy

Guzzi_Lamps.pdf

[raz]

Good stuff, Roy. Personally I don't see the point of adding a LED and keeping the bulb for the fuel though. But at least it will light up if the bulb breaks, so you wont run out of fuel without warning.

 

The charging light needed no special arrangement? I wasn't sure of that one.

[Kiwi_Roy]

Good stuff, Roy. Personally I don't see the point of adding a LED and keeping the bulb for the fuel though. But at least it will light up if the bulb breaks, so you wont run out of fuel without warning.

Raz,

I take it you used a resistor instead, about 120 Ohm I figure. You would need to use at least a 1/2 Watt to keep it from overheating.

The incandescent lamps has one slight advantage over the resistor in that it's resistance is low when cold (~10 Ohms), this should provide more current to the thermistor so it heats faster and it goes up to about 150 Ohms when on. Having said that I might have used the resistor but I didn't have one to hand.

How did you get on with the lampholders?

I haven't tested mine with an empty tank yet.

I doubt the bulb will ever burn out as it only turns on slowly but if it does it will be fail-safe as you say.

Cheers

Roy

[raz]

I still use bulbs, so I have no empirical input. I only had to replace a bulb once, and when I did I replaced all of them while at it. If they start to break more often I'll consider the switch.