Scooterotica

byron wrote:the tacho needs to be earthed to the engine/frame to work with the spark pulse.

Shame, If the unit could have earthed through a bridge rectifier, then this may have worked

Just to clarify, as there are conflicting drawings, does the battery fuse go on the + or the - side of the battery and what rating is required with two pathfinders @ 35watts each together with a H4 headlamp bulb?

Also, are fuses required on the relays, if so where and at what rating?

Thanks

If you're using one fuse to protect the whole machine just add up the maximum total load (watts) and divide by 12 to get the total possible current and choose a fuse above this. It doesn't matter whether it goes into the pos or neg side as long as when it blows it disconnects the battery from all loads.
If you wish to add further protection and fit extra fuses to individual circuits the same applies to working out the current (1 x spot, 35w/12v=2.92A) and fit the fuse in its positive feed close to the battery.

Will post a schematic of the system I use.... dc from a 12 volt ac supply....And I will convert a 12volt ac stator to a 12volt dc, for use with full wave rectification....and post a picture, and try and put a schematic with it....I Should have took a picture of the one Ive just done....But its gone now.....The dc conversion "full wave rectified" should run pathfinders.... And when its converted, you just need to follow the wiring diagram in the back of the Lambretta workshop manual (to wire the zenor and rectifier) which is a conversion that Lambretta did to there points condensor stators back in the 60's....this conversion gives a good consistant charge to the battery and bright 12 volt lights....But the dc current must be kept away from the Ignition system..... If the dc live wires come into contact with the green wire of the Ignition in the headset then the pickup on the stator can be burnt out in seconds...I speak from experience....and my mate wasnt Impressed.....

J1MS wrote:Will post a schematic of the system I use.... .

sounds good. thanks.
should my tacho work with that ? or will I have earthing issues ??

No I run a tach on both systems no problem... just earths to frame...

cool.
and thanks for rapid reply !

For those using points it may be worth mentioning the old school conversion.

Schematic on its way for 12 volt ac.. running a rectifier, battery and using a Lucas Zenor diode for clipping the ac pulses that occur...ie..... When you press the brake light and let it off again there is a voltage spike..I cant from memory remember how high the spike was but I think it was well over 20 volts for a millisecond ...this must be the delay in the regulator clipping excess voltage for some reason....Im not sure exactly what is going on..... I only know that this spike happens....So to prevent damage to my phone or Satnav.... I fitted the Zennor which seems to stop the spike in the voltage....But as I have said..... Ive run many Scooters wired like this... without the Zennor.....Just waiting for some assistance with the drawing then I will post...

This is first class stuff. Just what I joined the forum for. Keep up the good work and looking forward to the remaining diagrams/instructions :bouncing: :bouncing: :bouncing: