I am building a 24v e-bike and would like to add a kill switch that would cut power to the motor but I am afraid of a high voltage spike
- Thread starter Bighurtx
- Start date
SlowCo
1 MW
Most ebike controllers have brake switches/connectors that cut the power. What controller are you using?
slaphappygamer
100 W
If you are using a display, you can also introduce a switch on the battery positive between the controller and the display. I’m using a key switch, in the same place, on my system.
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docw009
1 MW
What kind of ebike are you building? Is it a DC motor powered right off a battery or does it have a controller box, Controllers always have a low current line that you switch to turn it on or off. Show a listing of what you plan to use if you don't know where it is,
Most Ebike controllers also have brake inputs which turn off the motor and leave the controller running. Well, I've never seen one that didn't have brake switches, but it's a big world,
Most Ebike controllers also have brake inputs which turn off the motor and leave the controller running. Well, I've never seen one that didn't have brake switches, but it's a big world,
Chalo
100 TW
If you use a dual pole switch on two of the motor phases, that will open the motor circuit without disconnecting the controller from the battery (so the battery will clamp the voltage on that side, and the motor's inductance will be taken out of the system).
It's easier to have a hard kill switch or yankable plug on the battery wire, but if the motor is spinning super fast, its back EMF could exceed the ratings of the components in the controller. I've not had that problem though, and that's where I put my disconnect.
It's easier to have a hard kill switch or yankable plug on the battery wire, but if the motor is spinning super fast, its back EMF could exceed the ratings of the components in the controller. I've not had that problem though, and that's where I put my disconnect.
DaLanMan
10 kW
you know there is a joke here about cross connection from the grips to the seat with a good 2-4 farad capacitor in line... Don't kill the battery, just the rider...
If you can't find a key connection option in your controller (I have one here that doesn't have one) and your controller also lacks a "brake engaged" connection, then the only option you have is an in-line interrupt somewhere. You can do dual connectors but that is literally asking for a surge clamp event. (which is what Chalo was talking about, it is when the disconnection occurs and it just throws an arc across the separation because the electrons are really good at follow the leader) There are ways to do this safely, but in all honesty if the line is hot enough...
Well
There
are
risks
If you can't find a key connection option in your controller (I have one here that doesn't have one) and your controller also lacks a "brake engaged" connection, then the only option you have is an in-line interrupt somewhere. You can do dual connectors but that is literally asking for a surge clamp event. (which is what Chalo was talking about, it is when the disconnection occurs and it just throws an arc across the separation because the electrons are really good at follow the leader) There are ways to do this safely, but in all honesty if the line is hot enough...
Well
There
are
risks
lnanek
1 kW
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- Sep 26, 2022
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The ignition switch sounds like it is high voltage if you check the specs, since it generally runs at full battery voltage, but it's usually just feeding a DC-DC converter to power the low voltage components in the controller and elsewhere like hall sensors at 5V and torque sensors at 10V. So I don't think it's prone to arcs and shocks. Low current as has been said. There are rotary battery switches out there commonly used on boats and the like that are rated for the voltage anyway, and of course, circuit breakers, if you really want the extra protection.
DaLanMan
10 kW
Like this I have used I think that exact model as a cutoff for a buddies trolling motor, it has been on his boat for 3 years now and despite new batteries, new outboard and new trolling motor (which departed the boat with a lot of noise and kerfuffle when he launched off a wake and got about 5' of clear air before we all found out how little suspension a boat has) it has sat there happily doing it's thing and not breaking.
