Engine on... 12v cutoff required...

[Berto]

Hi All. First time on the site, and it seems a good place to be.

If anyone is able to shed some light on something I'm trying to accomplish, that would be very handy...

I would like to wire a 12v supply, powered when the ignition is on but the engine is not running. The supply should cutout when the engine is turned over, or the bike is moving.

Your thoughts would be much appreciated.

Thanks all.

 

[davegs]

12Volt

What do you need to power with it?.

 

[Beemerman59]

Hi All. First time on the site, and it seems a good place to be.

If anyone is able to shed some light on something I'm trying to accomplish, that would be very handy...

I would like to wire a 12v supply, powered when the ignition is on but the engine is not running. The supply should cutout when the engine is turned over, or the bike is moving.

Your thoughts would be much appreciated.

Thanks all.

Switched power is easily solved with a relay and fuse box as an example. The relay is triggered from the parking or rear light circuit. Thats OK for the first bit but I'm lost in knowing how to then switch it off once the engine has started or the bike is rolling. That would need more complex electrickery. Might be easier to answer if we know the application.

 

[Deleted account 190920001]

Wire it with two relays a normally open linked to a normally closed. Signal the normally open from the park light which then flows through the normally closed. ignition on park light on relay closes. Signal the normally closed via the low beam. Engine starts, light comes on, energises the normally closed which opens and cuts the power. If you use miniature relays it wont take up much room. Depends on the load you want to run though as to what relays you can use.

 

[Berto]

Hi, and thanks for your replies.

The project is for some additional lighting around the bike that wouldn't be suitable (safe) when the bike is moving. I know it could be manually isolated, but wanted to have an automatic isolation for safety.

Would be ideal if just the key were present in the ignition, and someone didn't have to be sitting on the bike for the supply to be activated.

 

[Wapping]

Would be ideal if just the key were present in the ignition, and someone didn't have to be sitting on the bike for the supply to be activated.

The alarm can be armed and unarmed remotely, via a fob.

You might, with a lot of fiddling around, be able to power the lights 'on' when the alarm is turned 'off', perhaps? Or, maybe easier, turn the lights 'on' when the alarm is armed.

There is a 'park light' mode for the side light, activated by pushing the indicator tabs in some sequence or other (a search will turn it up). You may be able to piggyback of that, perhaps?

You might be able to bastedise a car ignition. For instance, my VW Golf recognises when the key is inserted into the ignition. From memory, inserting the key but not turning it, does something to the radio, leaving it on if I remember aright. I guess so the driver can listen to the radio with the rest of the car car shut down, but not leave the radio on when you get out.

PS Please tell us you are not adding some tasteless ground lights, like a chav Nova.

 

[Doofus]

Hi

It is normally very easy to achieve this sort of thing. Just find a +12v that is on with engine (e.g. headlight). This is the opposite of what you want, but easy to find.

Connect your accessory positive directly to battery (via fuse!) and connect your accessory ground to the headlight positive.

When the headlight is on there will be 0v across your accessory (because it will have 12v on both sides) and it will be off. When the headlight is "off", your accessory will be connected to ground via the headlight bulb and be "on". This is absolutely fine for low power accessories. If your accessory is high power (e.g. a few watts) it will not get the full 12v and your headlight will glow. In this case you just need to use a relay (i.e. drive relay as described above).

There is a chance the bike actively grounds the headlight positive when it is off (rather than just leave it floating), in which case your accerssory will be properly grounded, rather than grounded through the bulb filament.

I've often done this - e.g. to drive a flashing LED when the engine is off on bikes without an alarm.

Darren

 

[Wapping]

He's cracked it

Obvious, when I think about it.

 

[Berto]

Hi Guys, Thanks for all of your help and quick responses!

Definitely given me a good direction to start testing.

Wapping: Relax, no chav ground lights planned.

Will let you know how it goes.

 

[(RIP) Miff]

Are you not worried about flattening the battery???

If not, why not just wire them direct to the battery (via a fuse) with a master switch somewhere (under the seat to stop accidentally switching it on).

Or you could just carry a head torch under the seat...