I have a problem with the LED warning lights on my motorcycle project. In particular the LED indicator repeaters. Both the left and right repeaters glow all the time the ignition is on. In reality it’s not quite as bright as the photo below seems to show and they’re quite dim but you get the idea.. When the indicators are switched left or right, the repeaters flash brightly doing their job and the opposite warning light goes out. See below.. The flash rate is spot on. Looking for a way to stop the indicator repeaters glowing all the time. Do I need a resistor, a diode or a zener diode. Any suggestions welcome. Thanks very much. Stirlingmoz
If you use LEDs where filament bulbs were fitted, they dont have the behaviour where a bulb at zero current will be effectively a short, the cold filament has lower resistance than the hot glowing filament. Typical "12 volt" three LED stacks stop drawing current at 8 volts, so their resistance becomes very high at zero current. So if those green LEDs are wired across the indicator LEDs then they will glow even if only a few milliamps is being fed to the main indicator circuit through an electronic flasher circuit.. with filament indicator bulbs they will not light. Also you would find if you disconnect the green LEDs then the external LED indicators start to glow. Do you have a circuit diagram of how those green LEDs are wired? The current sink idea I put up a schematic of a while back on another LED thread is a way to bleed off current without producing a lot of heat..
@mikedjames I was kinda hoping you might reply Mike I don’t have a circuit diagram - sorry. I’m using a Motogadget M Unit as the heart of the bikes wiring system. It’s a motorcycle thing but a kind of a can-bus system. Far cleverer than me. If you are able to share your current bleed diagram I’d be very interested. I was hoping it wouldn’t affect the indicator flash rate as that’s spot on at the moment. Stirlingmoz
This is a current sink.. basically once the current goes over about 50mA the current stays constant. (The GaAs Red LED is used as a voltage reference so its hidden in heat shrink.) use one of these circuits for each side . With LEDs on the corners of the bike the blown bulb detection of the switch box wont work properly anyway (probably report bulb blown) , this circuit may also confuse that function by appearing as a good bulb.... Omit the pair of diodes- this circuit is used in my bus as a current sink to make the dash LED indicator brighter, where the wiring is different. I expect it's the "lamp test" current of that rather cool switch box that you are using that is lighting the LEDs..
Wow Mike. That looks quite electronically complex. What would be the consequence of putting a 1K ohm resistor in parallel on each circuit ? Thinking there must be a good reason for your solution. Stirlingmoz
It has to be just the right value and the power rating goes up as the current increases. One quick fix is dump the LEDs in the cluster and use small filament bulbs.. Or try 100 ohm 2 watt resistors across each indicator circuit. It's called a constant difficulty theorem.. find a neat solution to something and it causes another problem which is just as hard to fix.
