Anti-theft relay with no power drain

[auraslip]

When you trigger the relay, it latches shut connecting all three phase cables. This makes the wheel hard to turn. I know the infenion controller already has such a feature, but it requires you to leave the controller powered on which means stand by amp drain. Because this relay is latching, it will stay open or closed until it's coil is powered up. The two momentary switches are added for security against accidental or other un-authorized usage. Keyswitches would also be acceptable here.


Question for the community: I'm terrified of the relay activating while riding. What are the chances of this? Although no current travels through the phase cables, is their a risk that the high voltage of the phase cables may spark across? Would thicker cables need to be run to the relay or would 20 gauge wire be fine?

 

[Alan B]

Many latching relays can be actuated by a physical bump. So hitting a pothole might put you in full ebrake.

 

[fizzit]

Maybe put a fuse on each phase so that if it gets activated while moving, the fuse will quickly blow instead of the wheel locking up.

 

[auraslip]

Alan, Isn't it the case that latching relays on actuate accidentally only in one direction? Like a normally closed relay would get bumped in an open position and close but not the other way around?

Fizzit, good idea. Will definitely do that if I use try this.

 

[Alan B]

Depends on how they're made. They are bistable, so they can sit in either position and the coil(s) can move the armature. A mechanical impulse can also flip it to the other state. One state may be more likely than the other, depending on the mass distribution and the mounting direction and direction of the motion. It might take more force than you would have, you could test it by banging the relay on the table from different directions. The larger the relay the higher the force likely required to trigger it. Shock mounting it on rubber may help also.

I've had friends motorcycles stolen out of backyards and they had to be lifted over tall fences. The amount of security this actually provides is pretty small.

 

[auraslip]

Truth Alan. You could just snip the phase cables or unplug them. Definitely wouldn't be good for anything but a quick pop into the store.

Since it'd only be a quick lock down and amp draw wouldn't be much of a problem, it might be better to just use the anti-theft features in the controller.

I'm trying to make a system that only needs one key switch, but two would definitely be easier; One keyswitch to connect the ignition wire or main power relays, and one key switch for jump that anti-theft jumper to ground.

 

[auraslip]

What do you think of this? Key switch to power up relay that controller iginition and the power to 12v accessories. A momentary switch and spst toggle switch to lock on a DPDT relay that connect ground to the anti-theft jumper on the infenion. The only way to turn the DPDT jumper off is to turn the keyswitch.