Initial Idea

posted Jan 21, 2013, 11:59 AM by Bill Bai   [ updated Jan 22, 2013, 11:10 AM ]

Hi there,

I saw your PCB design offer. Sadly, I don't have a schematic as I've not been able to identify the parts I need, so I'd feel bad asking in that thread.

Basically, I'm trying to build a power solution for my bike. Most cars have an accessory loom that provides filtered 12V power behind a fuse - bikes don't. This makes connecting things like GPSs, communication systems, heated grips and automatic oiler systems a PITA.

What I'm looking to do is take a connection from the battery via a relay and a fuse, then break that out into

  • 12V that can deliver up to 11A (terminating on 2 screw terminals)
  • 5V filtered for audio devices up to 0.5A (terminating on 2 screw terminals)
  • 5V unfiltered for other devices (terminating in a dual USB connection)

It needs to fit under a motorcycle seat which doesn't have a huge amount of space.

The basic schematic is at

I've not been able to identify the right components to do this though. Firstly, finding an appropriate dc-dc solution for the 5V 3A solution that costs less than GBP10 per unit has eluded me. Secondly, identifying the correct values for the caps and inductor for the filtered 5V connection is beyond me. Lastly, working out appropriate track sizes, etc. to carry the amount of amperage I want to be able to draw is a dark art to me :)

Ideally, I'd like to see the design licensed under the Creative commons Attribution-NonCommercial-ShareAlike 3.0 Unported license with attribution to you if that's acceptable ?



Note: edited for privacy