Wiring logic for starter button

[pupp]

Anyone fitted an aftermarket starter button? Want to do this and have obtained a nice quality ally button from Peninsula that sadly came without any wiring suggestions at all. I'm assuming a relay (guess about 30-40 amps will suffice) will need to do the load switching in place of the lock barrel and that's easy enough. However, would like to rig up some sort of circuit that prevents the button operating the relay once the engine is running (just in-case of accidental pressing)...ideas anyone? The switchgear on the button is twin pole with momentary contact and take-offs on each side for 'make' and 'break' respectively.

Additionally, the button is led illuminated and I'm sort of assuming the feed from this can simply be from the battery/charge idiot light. That way the illumination is only on when the engine is not running. Any other options?

[TEXET]

Hi pupp, email me for required logic, oh and I'll throw in the password to access my bank account. No,No,No, thanks are just not necessary.

[joospeed]

you could have a relay operated from the charge warning light wire? .. i think the coil resistance shoud be over 70ohms to not interfere with the circuit operation .. use the relay to switch the light and the starter button feed , only works the button when the charge circuit stops ,er, charging ie when engine stopped ..

[joospeed]

better way still might be to earth a relay through the oil pressure switch ..

[Ballistic Banana]

David Beer of Modwise was does one HERE
I am sure if you drop him a line he may send you his kit. It looks like it includes arelay in the wiring and I am sure he will prehaps give you a price without the actual button??

BB

[Apache]

pupp said:

Anyone fitted an aftermarket starter button? Want to do this and have obtained a nice quality ally button from Peninsula that sadly came without any wiring suggestions at all. I'm assuming a relay (guess about 30-40 amps will suffice) will need to do the load switching in place of the lock barrel and that's easy enough. However, would like to rig up some sort of circuit that prevents the button operating the relay once the engine is running (just in-case of accidental pressing)...ideas anyone? The switchgear on the button is twin pole with momentary contact and take-offs on each side for 'make' and 'break' respectively. Additionally, the button is led illuminated and I'm sort of assuming the feed from this can simply be from the battery/charge idiot light. That way the illumination is only on when the engine is not running. Any other options?

feed the supply through the N/C contacts

[pupp]

Ok, some more help needed on this please. Both the oil pressure and the charging lamp ideas (I think) are not going to work. When cranking the car (on the key for now), both lamps dim (due to the current drawn by the starter) and actually go out a moment or two before the motor fires. Although I've not tried it, my best guess is that a relay driven off either of these circuits would not stay closed long enough to allow the starter to function properly, or would 'stutter' as the supply fluctuated (unless some form of 'delayed' feed could be arranged).

Now wondering how likely it actually is that the (button) starter would be inadvertently operated. I've managed to avoid this for 20+ years in key-start cars and for longer on motorcycles that have button starts. Am I worrying about a problem that doesn't really exist? The button depresses into its surround to operate BTW...it would need to be a positive press, not a glancing knock.

[5ltr-chim]

First thoughts :

Have you considered the pulsed signal to the tacho ? or thinking further out of the box - reverse baising a zener diode of the Alternator output ?

[GreenV8S]

The setup that seems most common is a toggle switch for the ignition/fuel with a flip-up guard to stop it being knocked on/off accidentally, and a starter button without any special protection. Since this is so common, I guess most people don't find it a problem.

[Apache]

KISS.........works every time

[kevinday]

Being a techno weeny, I would think of taking the wiring off the ignition switch and applying it to the button, such that the ignition switch works the ignition and the start position wiring is now controlled by the button instead of the switch. Some techno giant can tell me why it wont work......

[900T-R]

I did it that way - I'm not sure why everyone talks about relays and such. You're actuating the starter solenoid, not thestarter motor - I can't imagine it drawing 30-40 A current as some DIY guides say, and if it did:
a) why would the ignition switch cope, and a pushbutton switch not?

b) why's the wire running to the 'start' position of the ignition switch (the one you take out and run to the pushbutton switch instead, the other end being a switched + 12V source) 1.5 mm2 thick, and not at least 10 mm2 (4 gauge)?

[pete]

I thought the whole complication was wiring the starter button so it's only "live" when the engine isn't turning? Otherwise there's the danger of accidentally pressing it while motoring along, which has a good chance of stripping teeth off the flywheel or pinion

If you're willing to risk it being live whenever the ignition is on, then it's child's play to wire it up in the same way as the ignition key switch.

I'd recommend the route of a relay activated by the "battery discharging" warning light (as Joolz has already suggested) - this should stay lit while the starter motor is running, as the starter will be drawing so much current that the alternator has no chance of keeping up! Should be more useful than the oil pressure light in that respect.

Pete

>> Edited by pete on Sunday 4th January 00:52

[wedg1e]

900T-R said:

I did it that way - I'm not sure why everyone talks about relays and such. You're actuating the starter solenoid, not thestarter motor - I can't imagine it drawing 30-40 A current as some DIY guides say, and if it did: a) why would the ignition switch cope, and a pushbutton switch not? b) why's the wire running to the 'start' position of the ignition switch (the one you take out and run to the pushbutton switch instead, the other end being a switched + 12V source) 1.5 mm2 thick, and not at least 10 mm2 (4 gauge)?

On most cars you're not even switching the starter solenoid from the ignition switch 'start' feed; you're feeding a relay that in turn pulls the solenoid in.
Must admit that on the few occasions that I've considered a start button, I've intended to use the alternator warning lamp output as a means to disable the cranking function... but not actually designed a circuit to do so. To be fair, I may have some electronic abilites that would allow me to resolve the issue easier than many auto-sparkies, but off the top of my head I don't have an instant solution to the (hypothetical) relay chatter that was mentioned earlier. It could well be that a combination of ignition pulse sensing and alternator warning lamp output would be needed (consider: if the alternator was faulty and the engine was running, it might be possible to engage the starter).

Ian

[900T-R]

pete said:

I thought the whole complication was wiring the starter button so it's only "live" when the engine isn't turning? Otherwise there's the danger of accidentally pressing it while motoring along, which has a good chance of stripping teeth off the flywheel or pinion If you're willing to risk it being live whenever the ignition is on, then it's child's play to wire it up in the same way as the ignition key switch.

I know, but before that even started putting in a relay was mentioned.

Anyone knows how 'diverting' the 'start' position wire to a separate pushbutton affects the safety feature of having to turn the key back to the parking position after a starting attempt, before continuity is allowed back to the 'start' position?.

[dannyboyo]

With a start button, the start "lock" feature would be irrelevant i'd imagine. As long as your key is in the IGN position you could bash away at the start button as many times as you want and the engine would crank.

[graham66]

You could always earth it through the reverse light, so it would only work if the car was in reverse - adds a security feature as well (what thief would think of putting it in reverse to start it) and then the button would not work while driving along (forwards)

Graham

[wedg1e]

graham66 said:

You could always earth it through the reverse light, so it would only work if the car was in reverse - adds a security feature as well (what thief would think of putting it in reverse to start it) and then the button would not work while driving along (forwards) Graham

The problem I have with this is that you are now asking the starter to crank the engine over with the clutch depressed. So you are forcing the flywheel, and hence the crankshaft, forward against the crank thrust bearings with NO OIL PRESSURE. Bad idea.

[kevinday]

My simplistic head on again, why not have a simple on/off switch in line with the button, turn it on to start, and off when the engine is running?

[pupp]

Ok, job done. I opted for a simple relay to switch the solenoid load (despite what's been said earlier, I don't think there is a relay in this circuit as standard...the wiring back to the ign lock is hefty and I tested continuity to the solenoid. This appears to to tally with the wiring diagrams I've seen). I've got no 'safety' measures in place except for a recessed button that needs a good push and a sharp slap for anyone that looks like meddling on the move I like the result with the button sitting below the fuel guage.