Emergency cut off switch---yes or no?

[PJIII]

Lately I have been running across references to an "emergency-cut-off-switch for e-bikes. They are mounted for easy & quick access by the rider in the event of a controller or throttle gone-WILD and interrupt the primary wire to the battery as shown in the drawing. One would have to use a 40 amp or so switch or possibly a fuse you could grab in a hurry. With Toyota's Prius in mind it might not be a bad Idea! I think I might do it.

I know we have e-brakes but what if that circuit fails along with your throttle because the controller fails?

I am curious as to how many of you have them installed along with the method of installation and location of the switch.

 

[dogman dan]

With my controller mounted behind the saddle, I can easily find and yank out the andersons between the battery and controller. Just reach under the right cheek and yank. If I dare to let go of the bars with both hands!

 

[deardancer3]

Yep, a 50 amp switch easily reachable.

easy enough to do, just mount the switch anywhere on the battery oputput with a string to your seatpost.
Reach down and pull the string, tripping the switch. no long unsightly runs of 10 gauge wires.

d

 

[Zoot Katz]

I bought this one.
It's mounted in the battery box where I can shut it off with my foot. I figure that was a good place since both hands will likely be busy grabbing the brakes.

 

[amberwolf]

I did it like Dogman, except mine's any of the inter-battery connections on the frame of CrazyBike2 between my knees, on the right side. But first I would try the circuit breaker I can flip on the left side, before yanking plugs--only if the breaker fails to let go would I pull the plugs.

Before either of those I have a run/stop switch on the bars next to the shifter and throttle that cuts off the throttle to the controller, and the keyswitch in the steering post also in series with that. If it's not a MOSFET failure it'll probably stop the bike right then.

But I can definitely say that full-throttle, just the brakes won't stop CB2 from moving even if I started out from dead stop, at 48V. If I'm already moving down the road, and the motor couldn't be shut off, forget it.

 

[AussieJester]

Yep, a 50 amp switch easily reachable.

+1 same here... Highly recommend it as do race organisations on
race cars, the switch should be clearly marked with an "on/off" to for others to
switch in case your unable to for what ever reason..sprawled out
half dead on the road, hanging from a tree or the front windshield
of a car etc etc...

KiM

EDIT:

Was interupted TAXI arrived to take me to electronics store funnily enough haha
wanted to add this pic of the particular type switch that I use.

 

[coln72]

Aussie, is the switch your talking about one of those battery isolation switches used in motorsport. The ones with the red T handle????

 

[dogman dan]

Brilliant idea, putting a switch you can activate with the foot. Kill switch for the throttle wire is pretty smart too! I guess a controller could fail so throttle imputs didn't matter, but most runaways are from wet throttles shorting, or other reasons for a shorted throttle.

 

[Drunkskunk]

I had a key switch on my first bike, but finding it, grabbing it, and turning it the right direction in a panic could be improved on, so my next two bikes I routed the battery wire close to the top tube on the frame, with the connectors on both ends angled so it could be pulled free easily.

 

[AussieJester]

Aussie, is the switch your talking about one of those battery isolation switches used in motorsport. The ones with the red T handle????

Exactly, sorry the image wasn't showing i have edit the post and upload pic to ES server it should be
viewable now Works a treat have it connected directly off the battery shuts down all
electrics on the bike.

KiM

 

[PJIII]

I had some time to look so these are the various 50 amp or so switches I found. Some are quite small which surprised me. It may be that one of these will work for you.View attachment 8View attachment 4View attachment 8

 

[AussieJester]

The Moroso switch is exy

KiM

 

[FeralDog]

If 'on-off-momentary' doesn't bother then

http://www.basspro.com/webapp/wcs/s...6_225000000_225001000?cmCat=CROSSSELL_PRODUCT

 

[PJIII]

Ok, I had some more time so here are some various clamps you may want to use for switch mounting or for other things.View attachment 4

 

[John in CR]

With brushless motors you don't need a heavy duty switch, just one in the right place. All you have to do is be able to turn the controller off, because without the controller powered up there's no failure that can continue a runaway condition. An on/off switch for the controller and a fuse on the battery lead is all you need. The need for high power cutoff switches is just a carry-over from brushed motors where the ability to cut the battery power is a key safety issue, because the motor only needs + & - , so even total controller failure could result in a runaway condition.

Personally, I prefer key switches so an unsuspecting kid can't flip a switch and twist that throttle, creating a real problem for him and your bike. Also, I know with just a switch I would often forget to turn it off, which puts the battery at risk along with anyone walking by with the urge to goose that throttle.