switching issue.

[piratepaul]

What about a short fuse Rick?

[Richard]

Yes - can't have too many fuses in vehicle systems!

[piratepaul]

Moderation: Abusive post removed.

[piratepaul]

That said... I would suggest you only switch on at low revs to prevent damage to the alternator.

Perhaps a switch with an LED, lots on eBay. When you switch the ignition on, if the switch is on the relay will be closed.
If that is not what you want, I suggest a momentary switch, 12/5v voltage converter(£2 eBay) a flipflop and transistor.

[piratepaul]

The flipflop would need to have a clock input and would have a special name, I'm not sure of the name off the top of my head. If you want to go down this rout let me know and I will find you a suitable chip.
It doesn't need a clock, just a clock input for the button.
You also need a bit of strip board. About £10/15 all in I should think. Don't be put off by the word chip, its a very simple chip.

Tar&stuff.

[Richard]

I an not prepared to put up with gratuitous insults when I am trying to assist. Sort things out in your own way.

[piratepaul]

What does it look like I'm doing, If he wants to proceed I will.
At least it not but poo.

Slanderous comments rick.

Tar&stuff.

[piratepaul]

Insult to follow, bull poo.

Tar&stuff.

[Clip Rite Andy]

I should think you want a 50A + relay, you might get away with a bit less but...

I am getting one myself, thanks.

Tar&stuff.

Hi Paul. I.will be using a transit relay. They fit them in cars that come off the factory floor before going into the dealership. It is rated to 120amps I believe. It just has a simple 2 prong connection which is wired back to the ignition so when the car sits idolly the battery is completely disconnected, but swithing on the ignition triggers the relay. All you do is connect it to the neg terminal on your battery, these are already the right size to fit over battery terminal and has another stump to fit the cars earth lead to. Jaguar used to use them. I have mine kicking around in my garage from nearly 10 years ago.
Kind Regards
Andy

[piratepaul]

OK the relay sounds perfect.

Are you happy with a switch and LED, or do you want a circuit and a momentary switch?