wiring up a key switch help please

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Jan 5, 2015
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hi I want to use a key switch on my new ebike build but im not sure how to wire it up, if I wire up the natural from the battery permanent going to the controller and have the live going through the switch to the controller will that work and be safe any advice would be helpful


chris
 
If your controller has two red power wires going into it one big, one small, then you can put a switch in line on the smaller wire.

If not, then using switches for the main power wires is not a good idea. Small affordable switches fry, and switches rated for it (DC) cost a fortune.

Just unplug for the switch. If you want it locked off, take some of the wire with you. 2 sets of plugs.
 
If your controller lacks the small gauge 'ignition' wire for a low power switch, you can simply use a DC breaker as a combined main on/off switch and protection on a main power lead. This has been used and posted by many - I have 10000+ miles on mine - works like new.

This post has links to low and high voltage/amperage units (marine and solar breakers respectively). Amazon carries these if you don't want to shop around...

To buy some headroom, choose a breaker about 150% your planned max current.

Cost is a modest $15 to $30.
 
If your controller has an ignition wire, like many do, you can use virtually any swtch you want because the current is low. If it doesn't, but you have a BMS in your battery, you can put a switch on that. It saves a lot of messy heavy wiring. Your BMS already has a switch to switch off the battery, so you might as well use it.
 
Yes, a big switch like that will work.

Cost is not so modest IMO. Not when just unplugging a decent plug like a 45 amps Anderson or 4 mm bullet is only about 2 bucks. And, you likely have a plug between battery and controller anyway.
 
csjones10d said:
I want to use a key switch on my new ebike build...
If you were going after lightweight security and not just on/off capability and your controller lacks the small gauge 'ignition' wire, then you might also look to the key switch to disable the controller as distinct from switching the power. Here you can just wire your key switch across the ebrake wires. In this configuration the bike might be powered up but the throttle will be inoperative.

For this approach you will need a key switch that allows the key to be removed in the ON position. Common security key switches allow the key to be removed in either position and are readily available from eBay. This is a 5v application with negligible current so there are no pressing electrical requirements. (Such security switches are also suitable for the 'ignition' wire approach mentioned above where the voltage switched is the full pack voltage but the current is small and arcing is not an issue.)

  • FWIW - I use a main breaker with both kill and key switches to address different riding situations.
    • For daily riding to/from my house with no parking, I usually use only the main breaker for convenience and absolute power disconnect.
    • For short periods of public parking I use the key switch + breaker and frame lock (and optionally a chain + lock as well).
    • For standing and chatting on the bike I flip off the kill switch (in series with the key switch on the ignition wire).
    One size doesn't fit all - but that's just me... :D
 
That definitely works for security.
 
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