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 yo
For a bicycle I don't bother with emergency cutoff and don't quite see that it's so important. For bigger (faster) vehicles I agree it's important. My motorcycle has a big red switch front and center that acts as both main ON-OFF and emergency OFF.
Most controllers have a failure mode that is full ON full power. The only way to stop if the controller gets in that mode is to wait for the battery pack to wear down. Obviously it's desirable to stop before the pack wears out.
The switch would be placed as you suggest. The switch has to be rated for enough current to handle whatever the controller takes - more actually. Switches rated for less might have their contacts weld shut and be ineffective in turning off power.
- David Herron, The Long Tail Pipe, davidherron.com, 7gen.com, What is Reiki
Or, if you have a relay rated continuous and a switch to turn on the 12v dc-dc converter to your lights and relay LaTeR
thank GOD I wake up above ground !!!!
Good Lord man!!!---a full ON failure mode!!! That I did not know. Thanks! Now I KNOW I am going to install an emergency cut off switch on my bike. I hate to think about approaching an intersection in heavy traffic with a controller failure. I'll post the parts I find when I find them.
Cyclone 650 watt 24V trike
Although the relay may work the contacts can & do arc together at times & why ad a DC/DC converter when you don't have to. I think a switch is a more fail-safe way to go.
This is a battery cut off switch rated for the purpose & is commonly used on boats.
This is about as small as a 40 or more amp switch can be made.
There is another route & that is to use a "contactor"---it is similar to a relay but specifically designed to switch large amounts of power. You would treat the contactor like a relay for wiring purposes so you could install the contactor, say, near the batteries & then run small guage wires to the light duty, say, toggle switch
Cyclone 650 watt 24V trike
The CuMoCo C130 I'm testing has a 'winter storage' switch under the seat, next to the main circuit breaker. It cuts all power draw from the batteries, even the relatively low draw for the bike computer. I hadn't really thought of an emergency cutoff, and can always just turn the key off if there's a throttle emergency.
However, it still might be useful to put this switch on the dashboard. If nothing else, I can see police/fire people wanting to kill all electrical power after a fall. Motorcycles with a gas engine always have an engine cutoff switch next to the throttle, essentially for this reason. It sorta makes sense to extend this to a battery cutoff switch.
My electric vehicle: CuMoCo C130 scooter.
CuCoMo, I agree with your thinking---it just takes one situation you don't anticipate to KILL YOU! I would rather be safe than sorry. I have a thread going here Thread where all can see the different types of switches I have found along with others so they can custom install theirs to suit their specific needs.
Cyclone 650 watt 24V trike
Hi guys,
i would like to point out that only *brushed* motor controllers fail full on.
Even the Chinese EV industry moved away from brushed motors 5 years ago.
they are now almost unobtainium.
BLDC motors (which every 2 wheeled EV in the past 5 years uses) fails most commonly off, or with a locked wheel (short between phases).
a full on failure with a BLDC setup only happens when the accelerator signal fails.
still an easy shutdown, use your key
most setups cut-out on break activation aswell.
so, unless you are using a brushed motor setup, don't worry.
Matt
Daily Ride:
2007 Vectrix, modified with 42 x Thundersky 60Ah in July 2010. Done 194'000km