odd project requires a odd cuicuit.

[qwakers]

hi
i have a bit of a odd problem.

basically, on my motorbike, the headlights are on all the time from when you turn the ignition on

i want a circuit that will leave them off until I activate the starter.

to articulate that a bit better, I want a circuit that will turn a relay on, only after it has seen the starter go live and then dead again.

can anyone help me with this?

many thanks

 

[tcmtech]

Just tie the relay into the alternator so it only activates the lights when the engine is running.

 

[qwakers]

i didn't really want to do that because if the charging system fails, the lights would go off. that might sound like an advantage, but i don't want the lights going off for any reason when its running.

 

[OlPhart]

You could get all fancy with an ammeter kicking the relay on going into positive charge. Or You can be the intelligent controller with a Switch.... <<<)))

 

[ericgibbs]

hi,
If you would prefer an electronic system, this is one option.

A 12V n/o relay with contacts rated to suit your lighting load.

Ignition ON, puts 12V to top of relay coil

Starter engaged, after a 0.3Sec delay via R4/C1, Q1 energises the relay, Q1 is latched ON via R3 from the light supply.

Diodes D2 and D3 are simple blocking diodes.

A Manual [optional] Lights ON over ride switch.

When Ignition turned OFF the relay de-energises and lights are OFF.

 

[qwakers]

Thanks. that was what i was looking for.

 

[crutschow]

My Honda simply had a relay coil connected to the starter switch. The NC contact on the relay was in series with the headlight. That disconnects the headlight when you activate the starter, which is all you need. The short draw of headlight current between the time you turn on the ignition switch and activate the starter normally has negligible effect on the battery charge.