View Full Version : Keyed switch

10 September 2013, 0834
I'm parting out components for my EV build and I can't seem to find a good keyed switch. I'd like one that is double pole/throw so I can turn the key into the first position to turn on the 12v accessories and then the 2nd position for the HV system. I'd put in some covered rocker switches but I like the security of a key. Would a key switch from the original motorcycle be usable? Anyone have any suggestions or links?


Also, has anyone had luck with integrating breakers instead of fuses into their system? I'm just curious.

10 September 2013, 0900
For ignition switches, a salvage yard might have them. I know many boat parts suppliers have them. Aircraft Spruce also has them, but chances are they will have the "aircraft surcharge" to make them too expensive.

Ignition switches are usually rated for 12v (and sometimes 24v). So, you can't run pack voltage through them. But, you can still use them to control a relay or contactor rated for pack voltage and/or current.

Sorry, no experience with breakers.

10 September 2013, 1116
I agree w/ robo. Don't run pack voltage through the key switch; use it to control a contactor.

Here's what I did. The keyswitch turns the DC-DC converter on to enable the accessories, just like in the original gas bike. This also pre-charges the capacitors in the controller. The keyswitch AND the engine kill switch both need to be on to close the HV contactor to the battery pack. This is analogous to enabling the engine to run. So my startup sequence is key switch then kill switch.

10 September 2013, 1200
Why not use the original keyswitch? You can use a multimeter to see what contacts are closed in the different positions.

Also, use it to control a 12V coil relay with 150VDC rated contacts. Something like the Tyco KUEP series. That way it keeps HV away from the handlebars.

10 September 2013, 1212
These are great suggestions and clarifications so far. Thank you.

10 September 2013, 2050
Lowbrow Customs have a two position key switch which is perfect for switching the 12 V supply to the vehicle. A toggle on the right bar where the starter was can be used to power the main contactor.

DPDT versions would be great though, as you can power independent circuits in an isolated manner.

10 September 2013, 2310
I have my stock keyswitch turn on the 12V system, then the start button triggers a latching relay circuit that turns on the HV system. Sequence is keyswitch on, then push start. I just leave the run/kill switch on.

Actually, the latching relay is a circuit using a standard 12V automotive relay - it's not necessary, but I like being able to use the start button. Plus it's an extra thing you have to do to turn on the bike, which is sort of a safety feature.

I use a solid state relay to switch on HV to the controller (the low power input, usually labeled KSI). I just like SSRs because they have very low power draw, no mechanical contacts or moving parts, and handle high DC voltage. Mechanical relays like Travis mentioned are fine too. Just make sure whatever you get has contacts rated for DC voltage, not AC.

Haven't messed with circuit breakers. Fuses are small and cheap.

10 September 2013, 2324
Also - if you're using the original keyswitch from the GSX-R 1100, it has two circuits, so it's essentially a DPST switch (not that you need them both). It is also pretty heavy duty so you can run your 12V system through it - you don't need a separate relay for main 12V power. Same goes for lights, turn signals - all the stock switches are made to handle the full current.

Here's a mod I did of my GSX-R keyswitch so that it would turn off my DC/DC when in "park". Normally I just leave the DC/DC on all the time. Power draw is very low if there's no load.


11 September 2013, 1833
I just threw a DPDT key switch from my ICE Honda 400 in the trash today ( I converted it to RFID Keyless!) The wires have been cut, but there is still enough to splice to. You can have the switch for the cost of shipping if you want it.


send me a PM if you want it.