Key Switch for E-Bike

General Discussion about electric bicycles.
LI-ghtcycle   1.21 GW

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Key Switch for E-Bike

Post by LI-ghtcycle » Jan 24 2010 5:41pm

Hello! I'm looking at several of these switches, and I'm afraid of getting burned, most don't list the rating (amps @ volts) and many don't indicate if they come out in both the on and off positions.

I'd really like one that only comes out in the off position, but I don't want a gas engine's ignition switch, it has more than I need.

Just looking for something to handle about 1200 Watts of power going through it. (i.e. 22A @ 56VDC)

I found this one on Ebay http://cgi.ebay.com/Keyed-Ignition-Swit ... 1395wt_939

Any thoughts? Please let me know if you have found a better one, or similar for less $$$.

Thanks!
Thank you Justin_Le for your selfless act of kindness! We all are in your debt.
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Re: Key Switch for E-Bike

Post by LI-ghtcycle » Jan 24 2010 10:57pm

Kewl, yes thank you, I have one too, that I use the battery cut-off, and I want the second keyed switch to act as the "ignition" switch, and instead of a removable battery that I take inside, I want it to be secured to the bike, and just rely on the extra security of the keyed switch. :)
Thank you Justin_Le for your selfless act of kindness! We all are in your debt.
Back on track E-Bronco! Now with Cro Motor Mid-Drive Goodness!
https://endless-sphere.com/forums/viewt ... 28&t=44997

Vision R40 w/3000w MXUS as mid-drive, NuVinci N171B rear wheel as transmission, Silent yet powerful, running 72v 11.6 ah (20s 18650 Li-Ion) to climb hills, tow trailer with zero pedaling when needed!

https://endless-sphere.com/forums/viewt ... 28&t=75247[/size]

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Re: Key Switch for E-Bike

Post by amberwolf » Jan 25 2010 12:47am

All I did with mine, for my 2QD controller, is put a keyswitch off some Briggs & Stratton device (dunno what, got it in a box of "stuff") in series with the throttle pot's power supply wire. Breaking the contact disables the controller, since it has a safety feature that does so in case of a failed pot.

On the Curtis 1204 I used most recently, it has an actual keyswitch input to do the same thing.

For controllers that dont' have a key input or a throttle check, but *do* have an e-brake line, you could use the keyswitch "backwards", so that "on" is with the keyswitch in the open (no connection) position, and "off" is with it shorted, simply by wiring it across the e-brake line.

Then you don't need any fancy large expensive current-carrying switch. Any cheap old keyswitch will work. That includes keyswitches off the front of old computer cases, harddisk carriers, etc.

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Mark_A_W   100 kW

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Re: Key Switch for E-Bike

Post by Mark_A_W » Jan 25 2010 2:38am

I thought about a keyed switch...

But where do you keep the key? On your key ring with your other keys of course....


Then you have this enormous bunch of keys hanging off this tiny little key on your bike, over all the bumps. Making a racket till one day the key breaks....and you lose your house and car keys.


Think it through, that's all I am saying. A hidden kill switch may be more practical.
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Re: Key Switch for E-Bike

Post by amberwolf » Jan 25 2010 3:21am

My key stays on my "ring" only when in my pocket. In the keyswitch it's pulled off, since I use a "ring" that is just a quick-clip (like a micro-sized carabiner).

EDIT ADDED: Oh, BTW, LI-ghtcycle, that switch you link to could not switch the power you're thinking of. It *might* handle the current and voltage as long as you never move the key while power is being drawn, but if it ever moves off-contact while a load is on there, it will probably arc and burn the contacts. Remember that the ratings on it are for AC, and with DC those ratings will be MUCH lower.

It is the kind of switch (in general) that I am using for mine, in the "defeat" style use, rather than the "keyed power cutoff" style use.

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Re: Key Switch for E-Bike

Post by AussieJester » Jan 25 2010 3:32am

Mark makes a good point, the battery isolation switch along with a hidden cuttoff switch would
IMO is enough. I take the "key" from my isolation switch when i am going into the shops etc other than that though remains on the bike, regardless of what switch you use you SHOULD be locking the bike up with a good
quality chain/paddlock when your leaving it unattended, a pissy key switch wont stop a thief that
wants it from taking it...

KiM

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Re: Key Switch for E-Bike

Post by LI-ghtcycle » Jan 25 2010 3:43am

Good ideas, thanks all! 8)

I will need a switch to carry main power however, as I want this switch to also break the connection to my controller altogether, so that only my watt meter is draining the battery unless I'm going down the road, I want to eliminate the current draw of my controller.

I also plan on having a smaller key-ring for this purpose, it's another good point about a large key-ring breaking the switch, this is why on my car I have a separate detachable ring to save it's ignition switch too.
AussieJester wrote:Mark makes a good point, the battery isolation switch along with a hidden cuttoff switch would
IMO is enough. I take the "key" from my isolation switch when i am going into the shops etc other than that though remains on the bike, regardless of what switch you use you SHOULD be locking the bike up with a good
quality chain/paddlock when your leaving it unattended, a pissy key switch wont stop a thief that
wants it from taking it...

KiM
Yes, I agree, I use a hefty cable lock that goes through the frame and both wheels, but like you say, a determined thief will get it no matter what. I just don't want to make too easy so that a casual thief will be as tempted, and I plan on covering the batteries soon either with a "clam shell" ABS cover or a re-purposed black nylon garment bag with velcro to cover them up, just making them less noticeable and enticing.

I would just get a second switch like the one you mentioned KiM, but I don't trust that "key" it comes with to make it past about the 100th time it's used, I fully expect to have to drill a hole through the side once the flimsy "handle" breaks off. :wink:
Thank you Justin_Le for your selfless act of kindness! We all are in your debt.
Back on track E-Bronco! Now with Cro Motor Mid-Drive Goodness!
https://endless-sphere.com/forums/viewt ... 28&t=44997

Vision R40 w/3000w MXUS as mid-drive, NuVinci N171B rear wheel as transmission, Silent yet powerful, running 72v 11.6 ah (20s 18650 Li-Ion) to climb hills, tow trailer with zero pedaling when needed!

https://endless-sphere.com/forums/viewt ... 28&t=75247[/size]

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Re: Key Switch for E-Bike

Post by dogman dan » Jan 25 2010 7:26am

Simple me, I just unplug the andersons and rely on crackheads being to ignorant to know what to plug back in. Two sets of andersons, and you could carry the crucial 3 inches of wire into the store with you. And a cable lock too of course. A large fuse would also function as a switch pretty well I'd think.

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Re: Key Switch for E-Bike

Post by LI-ghtcycle » Jan 25 2010 10:40am

dogman wrote:Simple me, I just unplug the andersons and rely on crackheads being to ignorant to know what to plug back in. Two sets of andersons, and you could carry the crucial 3 inches of wire into the store with you. And a cable lock too of course. A large fuse would also function as a switch pretty well I'd think.
True, of course the crack heads are less common here than the meth heads, and these ones have a habit of stealing just the WIRE! :shock: :shock: (that's another really good reason to cover up my batteries :idea:)

But that's another good idea, I'm just a perfectionist, :roll: :lol: and I like the keyed switch for the aesthetics as much as anything. :mrgreen:

I know lots of people just have high-end connectors and plug & unplug them, but that big spark makes me nervous! :oops:
Thank you Justin_Le for your selfless act of kindness! We all are in your debt.
Back on track E-Bronco! Now with Cro Motor Mid-Drive Goodness!
https://endless-sphere.com/forums/viewt ... 28&t=44997

Vision R40 w/3000w MXUS as mid-drive, NuVinci N171B rear wheel as transmission, Silent yet powerful, running 72v 11.6 ah (20s 18650 Li-Ion) to climb hills, tow trailer with zero pedaling when needed!

https://endless-sphere.com/forums/viewt ... 28&t=75247[/size]

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Re: Key Switch for E-Bike

Post by PeteCress » Jan 25 2010 1:01pm

Mark_A_W wrote:But where do you keep the key?
My battery's key implementation is downright dysfunctional: it sticks out to the side where it can be broken off/yanked out if the bike falls over or snags on something. Last week, I lost the key carrying the bike through a fallen tree. Went back and found it, but still...

After that little wakeup call, I attached the key to a loop of thin bungee and threw a lark's head around a saddle rail.

Now if the key is pulled out it's dangling from the bungee. When I park the bike, I either flip the key up under the saddle where it cannot be seen or just pull it off altogether - depending on the location.

I keep the spare key taped to the seatpost with black electrical tape - so it's not visible and you kind of have to work to get to it.
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Re: Key Switch for E-Bike

Post by lshantz » May 30 2013 8:07am

Hey guys,

I just came across a very simple and inexpensive way to key lock the bike. I had a keyed switch, but it was not up to the task. It burned up after about 3 months of use. I came across it accidentally. I was going to use one of those red key battery disconnects, but they are not really designed for constant use, and I suspect they would fail soon.

I went to a local auto parts (AutoZone) and found a generic starter/ignition switch. It is rated at 30 amps, for $15.00! More than enough I would think. I then purchased a $4.00 aluminum enclosure from Radio shack and should have it up and running shortly. :D

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Re: Key Switch for E-Bike

Post by Tommy L » May 30 2013 8:24am

To be easy on your contacts, and for the contacts not to build resistance, wouldn't the pre-charge be a must?
Or do we just replace the connectors/switch every three months.

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Re: Key Switch for E-Bike

Post by lshantz » May 30 2013 8:33am

Well the original keyed switch I used was only designed for 3 or 4 amp I think. That is just not enough. With a 30 amp rated switch, the current flowing through it, should be fine. There is not much current when just turning it on or off. I suspect the problem is when the current is flowing through it, after turned on and you are accelerating hard. That is where an under rated switch is going to heat up and fail I think. I may be wrong, but that is what I'm thinking. I expect this switch to last the life of the bike now. Fingers crossed.

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Re: Key Switch for E-Bike

Post by ken1645 » May 30 2013 8:59am

I use this one. Seems to work great. Zip tied it to the frame. I run the positive of the battery through the key switch then to the controller. The ground stays connected through a 4mm bullet plug. At night I can see a small flash when turning it on but the contacts look fine and the switch is rated pretty high.. Might do a second positive battery connection with a 200 ohm resistor to reduce the flash & precharge the caps later on.

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Re: Key Switch for E-Bike

Post by Kingfish » May 30 2013 11:10am

I solved the problem a different way:

Rather than trying to switch high current - which will produce a profound spark unless it's buried in an oil can, I chose instead to intersect the power supply to the Voltage Regulator that drives the MCU. And for that - I used a simple keyswitch:

Image
On/Off Key Switch with 2 Round Keys

You can find this beauty at Amazon for $18 USD. Better deals are sure to be found.

I have mine mounted on the side of "Da Black Box":

Image
See it there to the left on the lower image... Very discreet. The chrome was blackened with a marker to reduce the magpie effect.
myself wrote:The other feature under the front faring was da Black Box that the DC-DC converter was attached to: This unit housed the relay which triggered the brake light from the ebrake (never worked and was disconnected). It also had the Left-Right signal indicator relay which did work – perfectly! Lastly it housed the key switch that disconnected the VCC-L to the Controller brains; this worked well too.
Anyways - this works fine for me - and still does. :wink:
Best of luck, KF
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Re: Key Switch for E-Bike

Post by Tommy L » May 31 2013 4:49pm

Just keep in mind that the "Current rush" into the controller Cap is still happening with a switch, even
though you do not see a spark. Pre-charge = longer Capacitor life :)

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http://www.rawvelocity.com

- 4th Hoolagan FS Mtn 9C-2810 with 128v nom 9.2ah A123 40S40P(1.2Kw) - Lyen 18Fet 4115 - 77.8kph :)
http://endless-sphere.com/forums/viewto ... =4&t=39480

- 3rd Catrike 700 Bionx PL350 Velo build
http://www.youtube.com/watch?v=rYdnkaAhVtI

- 2nd 150lbs Pusher Trailer
http://www.youtube.com/watch?v=Q1qTc4sjORY

- 1st Sears NS mtn bike - Rigid 10a drill 800rpm - 2 12v AGM - 1000 watt inverter - 600w dimmer for throttle, wicked torque!

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Re: Key Switch for E-Bike

Post by _Chris_ » May 31 2013 5:15pm

A key switch only really needs to switch a control circuit and operate either a solid state or mechanical relay and that ends up less than one Amp. For that reason you can buy a nice key switch cheap on eBay and hook it up to the coil of a relay rated well beyond your maximum draw current and that way you wont burn out your key switch or relay and then you will have to buy your devices only one time! It is better to use electrically a device to suit its correct load. That way you end up with a small key in your pocket. My first key switch was a marine one and it is really annoying in my pocket so I leave it in it tied to a pace of string on my bike because the key falls out when switched off.

This is all you need.

http://www.ebay.com.au/itm/4-wires-conn ... 94d&_uhb=1

http://www.ebay.com.au/itm/10Pcs-Car-Au ... c3f&_uhb=1

I found it hard to get a cheap relay rated at 36 v however if you wire these in series and parallel wire the contact terminals with solder and a thick wire (4-6 mm sq) you end up with a relay capable of switching 160A and you will never burn that out at 1200 w All you do is wire the coils in series as voltage is required your voltage = 4 in series, coils wired one to another and each relay is used for a multiple of 12V. That way as you step up or down in voltage you add or subtract a relay. Wire your key switch in series with the battery and relay coils. i.e. wire goes from positive to key switch, with small wire then other side f key switch to one side of series relay coils and the other side of relay coils goes to battery negative. A capacitor could be includedeither side of the relay contacts to be doubly sure it stops arcing when you turn it off and on.

Or use 2 or 3x 24v ones if it works

Its not wonderful but it does the job and you shouldn't break 20 bucks :).
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Re: Key Switch for E-Bike

Post by Bill Nye the science guy » Jun 03 2013 9:08pm

I bought a keyed switch for a car from an autoparts place , good for 50amps run, 70amps start. 15$

I don't here a pop when I turn the power on but if it craps out, i'll spend another 15$. handles 70v at 50amps with no heat build up.

been happy with it.
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Re: Key Switch for E-Bike

Post by sfiii » May 21 2015 3:19pm

Bill Nye the science guy wrote:I bought a keyed switch for a car from an autoparts place , good for 50amps run, 70amps start. 15$

I don't here a pop when I turn the power on but if it craps out, i'll spend another 15$. handles 70v at 50amps with no heat build up.

been happy with it.
Bill, just wondering how that switch fared for you, after 2 years of use. I have burned out more than one 30A+ switch myself, but I am running up to 1600W on my cargotrike (at 36V), so maybe it isn't an equal comparison. Still, wondering how it fared, since they are rated for 12V and you appear to be running potentially at much more than this on your e-bike. Also, do you use your ebike for cargo-hauling at all (i.e. longtail or trailer)? Just wondering how many amps continuous you might be running through that little switch?

Thanks!

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Re: Key Switch for E-Bike

Post by r3volved » May 21 2015 4:38pm

I use a breaker to switch main 72V and a key on my ignition line. Works great!
Works better than my big red key switch on my 48V bike main line.

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Re: Key Switch for E-Bike

Post by ddk » May 21 2015 10:22pm

I'm really really good about losing keys...
So I don't use them on my equipment.
I use a crap 12V 30A switch for my battery packs.
... worked great until that one day ~~~~dissolves into flashback mode~~~~
I decided to make my former 10s packs into 14s packs.
Suddenly I'm having switch failures!

Strangely enough, if I inserted the switch between the 10S and 4s sections I didn't have switch failures. :pancake:
Now, it absolutely shouldn't work like that, but it did.
switch.jpg
switch.jpg (44.89 KiB) Viewed 7061 times
The power connectors I use for the battery packs are interesting because you insert them, then twist clockwise to engage
(see pics)
not engaged.jpg
not engaged.jpg (40.65 KiB) Viewed 7061 times
engaged.jpg
engaged.jpg (49.93 KiB) Viewed 7061 times
This allows me to treat the connector as a hidden (in the open) switch
-which is the best way to hide things imo.
cannot tell first gen.jpg
cannot tell first gen.jpg (37.68 KiB) Viewed 7061 times
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Re: Key Switch for E-Bike

Post by d8veh » May 22 2015 6:16am

Most controllers have an ignition wire, which switches the power for the controller. You can use any switch because it's low current. The main battery current is blocked by the output mosfets, so doesn't really need to be switched. Modern controllers only drain a few microamps when switched off by the ignition wire, so you can leave them permanently connected.

Another option if you have a BMS in your battery is to switch it off. Many BMSs already have the connector for the switch. If not, there's loads of ways to make it switch off. A switch on any sense wire should do it or you can interupt the 12v to the output mosfets to switch them off.

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Re: Key Switch for E-Bike

Post by Alan B » May 22 2015 7:48am

d8veh wrote:Most controllers have an ignition wire, which switches the power for the controller. You can use any switch because it's low current. The main battery current is blocked by the output mosfets, so doesn't really need to be switched. Modern controllers only drain a few microamps when switched off by the ignition wire, so you can leave them permanently connected.

Another option if you have a BMS in your battery is to switch it off. Many BMSs already have the connector for the switch. If not, there's loads of ways to make it switch off. A switch on any sense wire should do it or you can interupt the 12v to the output mosfets to switch them off.
The low current 'ignition wire' is a good way to control the logic power for the controllers that have this. The ignition switch and the handlebar kill switch should control this logic power.

But many controllers have bleed resistors on the capacitor bank that will kill the battery in a few months or less if stored with the battery discharged. A DC circuit breaker on the main power can be used to fully shut power down when the ebike is stored for more than a few weeks.

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Re: Key Switch for E-Bike

Post by technopeasant » May 22 2015 11:23am

Here's a funny key story, but only my second post, so forgive the length...
I recently worked as a builder and on my first Specialized Turbo, the word from the senior builders was, "Don't lose those keys; they're German and cost a hundred dollars to replace." So we would dutifully zip tie the fancy keys to the bars and send the bike to the shop for eventual sale (a $6000 ebike sells well here). Me, ever curious about electricity, noticed the controller would fire up as soon as the in-frame battery was installed. So when a crack head did finally break a showroom window at two in the morning and steal a Turbo, the first question everyone asked, "Did he get the keys?" was corrected to "Did he get the charger?" The fancy key was just a battery case lock. Specialized!

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