LED power supply for small motorcycle

[clemence]

I think my first previous posting attempt failed due to my i'net connection. So, I'm posting a new one here.

Hello guys,

I'm a newbie here and also for the electronics. I need help in designing a complete LED power supply system for small motorcylces. It will start from the raw power generated from the alternator (rated at 0.1 - 0.2kwh at 5000rpm, depend on models).
The output would supply DC power for 4 XPG's (or 8 XPG's for dual headlamp models) at minimum 1,2A (1,3-1,4A would be preferred), 5 watt waterpump, and or 2-4 watt fan.
At 1,4A an XPG Vf approx. at 3,55V so each XPG would need 4,97watt. Thus, the power requirement would be 30watt or 60watt minimum for dual headlamp model.
Where should I begin with?

Many thanks in advance

 

[Foxx510]

When you say "raw" power, has it been rectified at all or is the just the straight AC from the coil? Is it a new or old bike? Older bikes can have very basic, dirty power systems.

 

[clemence]

When you say "raw" power, has it been rectified at all or is the just the straight AC from the coil? Is it a new or old bike? Older bikes can have very basic, dirty power systems.

The manual says that it's a single wave corrected (dunno, before or after the rectification). How can I check the ouput directly from the alternator to determine what kind of current it produced?

 

[Foxx510]

It sounds like it might be a dirty half-wave rectifier, which might be too dirty for a proper current regulated led driver. If you have access to a CRO you could look at the waveform and see how stable and clean it is.

 

[clemence]

It sounds like it might be a dirty half-wave rectifier, which might be too dirty for a proper current regulated led driver. If you have access to a CRO you could look at the waveform and see how stable and clean it is.

What is CRO? I checked the manual again and it seems that the half wave DC current come out from the alternator and then rectified by small regulator to make it stable under 15,8V. But still at very low rpm the voltage can go as low as 9V. I think its better to use buck-boost LED driver.

 

[Alaric Darconville]

What is CRO?

"Cathode Ray Oscilloscope", or, more commonly, just oscilloscope.

 

[Ken_McE]

I need help in designing a complete LED power supply system for small motorcylces.

May I ask what your goals and motivation are for this project?

The output would supply DC power for 4 XPG's (or 8 XPG's for dual headlamp models) at minimum 1,2A (1,3-1,4A would be preferred), 5 watt waterpump, and or 2-4 watt fan.

You appear to have an electric fan and waterpump on your list. This will be a power supply for all electrical items on your bike, not just lighting?

each XPG would need 4,97watt.

Call it 5 watts.

Thus, the power requirement would be 30watt or 60watt minimum for dual headlamp model.

You know, if you want to be hard core, you could have one power supply for the right hand side of the bike, and another for the left. The failure of either unit would still leave you with enough light to get home safely.