I am a little stumped on a problem that, for the time being, is purely theoretical, but if not addressed, will become painfully practical. I'd appreciate some insight!
I am redesigning certain components of my motorcycle's electrical system in preparation for a round-the-world ride. I'm probably fiddling too much, but so far my projects have gone unexpectedly smoothly. One of my modifications is to remove the ignition key circuit from having anything to do with starting the bike. Too many stories of people having to hotwire their own bikes due to some inept screwdriver wielders out there. The actual bypass is already done and working, just so y'all don't think I'm trying to get help hotwiring a bike (i actually left the key barrell in place, but when anyone tries to close its contacts with a screwdriver or by hotwiring, it closes a latching relay that prevents ignition until the power to the relay is interrupted by detaching the battery terminal from the battery...and I'm considering attaching my upgraded and loud horn to this relay to prevent continued tinkering by the would-be-thief).
The way the ignition (not starter, just powering the bike up) works is by using two relays tied together such that a momentary grounding of the coil of the first relay will turn on and latch the second relay, which provides power to all bike systems. Even though it requires two relays to achieve this mode of latching (negative impulse to continuous positive flow), i like it because it will make the momentary grounding switch easier to hide (i am actually toying with having an exposed wire terminal near a frame ground source that needs to be shorted with a metal object for this).
The trick is that i want to disable the latched relay with my existing engine kill switch. The solution is obviously to wire the switched end of the kill swich to the input of the second relay - the switch gets juice when the second relay is powered up by the first relay, and as long as the switch is closed, the second relay stays latched.
But the.kill switch also provides positive voltage to the primary coil in the ignition coil. When the switch is opened to kill ignition, and in my case also all power to the bike, that primary coil produces a pretty beefy inductive kickback. Problem is that i can't prevent this kickback because that is what enables the secondary coil to generate the high voltage necessary for ignition (20-40 kV).
My question is thus: can the inductive kickback from the primary ignition coil damage the coil in my automotive 12v relay, which is wired parallel to the primary coil and provides the only ground path once th switch is opened?
Part of my gut says yes, because these relays are usually used without protection diodes and can obviously handle their own back emf. But i would hate to lose the relay in a thousand miles.
Thanks!
I am redesigning certain components of my motorcycle's electrical system in preparation for a round-the-world ride. I'm probably fiddling too much, but so far my projects have gone unexpectedly smoothly. One of my modifications is to remove the ignition key circuit from having anything to do with starting the bike. Too many stories of people having to hotwire their own bikes due to some inept screwdriver wielders out there. The actual bypass is already done and working, just so y'all don't think I'm trying to get help hotwiring a bike (i actually left the key barrell in place, but when anyone tries to close its contacts with a screwdriver or by hotwiring, it closes a latching relay that prevents ignition until the power to the relay is interrupted by detaching the battery terminal from the battery...and I'm considering attaching my upgraded and loud horn to this relay to prevent continued tinkering by the would-be-thief).
The way the ignition (not starter, just powering the bike up) works is by using two relays tied together such that a momentary grounding of the coil of the first relay will turn on and latch the second relay, which provides power to all bike systems. Even though it requires two relays to achieve this mode of latching (negative impulse to continuous positive flow), i like it because it will make the momentary grounding switch easier to hide (i am actually toying with having an exposed wire terminal near a frame ground source that needs to be shorted with a metal object for this).
The trick is that i want to disable the latched relay with my existing engine kill switch. The solution is obviously to wire the switched end of the kill swich to the input of the second relay - the switch gets juice when the second relay is powered up by the first relay, and as long as the switch is closed, the second relay stays latched.
But the.kill switch also provides positive voltage to the primary coil in the ignition coil. When the switch is opened to kill ignition, and in my case also all power to the bike, that primary coil produces a pretty beefy inductive kickback. Problem is that i can't prevent this kickback because that is what enables the secondary coil to generate the high voltage necessary for ignition (20-40 kV).
My question is thus: can the inductive kickback from the primary ignition coil damage the coil in my automotive 12v relay, which is wired parallel to the primary coil and provides the only ground path once th switch is opened?
Part of my gut says yes, because these relays are usually used without protection diodes and can obviously handle their own back emf. But i would hate to lose the relay in a thousand miles.
Thanks!