E-bike brake-lights via $5 relay

I do not intend to promote any particular relay brand nor vendor; any relay with a matching configuration will work fine. The relay is 5 Volt DC, has a total of six pins; with 2 normally-open non-shared sets of contacts.
The particular relay used in the video-mockup is an Omron G6B-2214P-US 5 VDC (pdf data sheets and specifications are available online).
Note: This modification is intended for bike-conversions, but it will also work on factory e-bikes. However, if you do not have the skills or understanding to work with basic wiring and electricity, you will struggle to make this modification by yourself.
But don't worry. If that is the case? Just find a local e-bike shop, and show their service technician this video. They will be able to set this modification up for you.
Naturally you will lose your Do-It-Yourself discount, because you won't be doing it yourself. Expect to pay your e-bike technician's normal shop-rates for the modification.
Best of luck with your projects, and ride safe everybody!

[@schrodinger3467]

Thanks! This gave me a hint on using 2x 12V 10A 5-pin SPDT relays instead since my tail/brake light is 12V, and those relays are what I have laying around. The 1st relay toggles and powers the brake light, while the 2nd relay also toggles but merely shorts the "low-level brake input" wires for the controller--replacing the brake lever action, since it essentially does the same thing.

[@SaberToothBicycle]

Nice job! Yes, that's a good adaptation. The version I made, being powered by the 5V sensor-power source from inside the controller, can use any voltage of brake-light--and that's advantageous for two main reasons. First, because e-bikes operate on a wide range of system voltages (36V to 72V are common enough), any choice of brake-light and voltage will be compatible. Second, the low-voltage low-current (5VDC) going thru the e-bike brake-handles (out there in the rain) prolongs the life of the microswitches in the brake-handles. On my bakfiets, I also use two relays. I use that little one from my video as a trigger-relay for an off-the-shelf automotive 12V relay--which controls the brake-lights. I chose this, because I have more lighting (along with trailer lighting circuitry) so my total brake-light amperage was getting close to the limit of that little Omron relay. Best of luck with your project! Ride safe!

[@ChrisB...]

The brake circuit was the hardest part to figure out, but eventually I got it right with a few relays (shift sensor signal also feeds into the brake signal). I also have a key-on 12v circuit that is dimmed to around 11.2v via a resistor so I can use my brake lights as running lights, made everything double hard because I had to put a diode on all the 11.2v lines to keep the brake relay from tripping via back voltage. Overall it was a very satisfying problem to solve.

[@SaberToothBicycle]

Thanks for the comments, Chris B Nice job customizing the concept to work with your own particular system! Well done! It is a very satisfying feeling when the puzzles come together. Ride safe! And all the best!

[@Jerbrown]

Can you help me? :)

[@przemoet]

that's a very cool and simple solution. well done

[@SaberToothBicycle]

Thank you!

[@xfunkyflipx]

Hi, I would like to have a copy of the wiring diagram. Going to be helping a friend add brake light on his trike using your method.

[@SaberToothBicycle]

Thanks for taking the time to comment! My compliments to you--I think it's really cool that you're trying to help out your friend. If you scroll thru these comments, you'll find where I've helped someone find a nice big version of that thumbnail-image, which I posted on an e-bike forum page. I've never actually made one myself. But between that image, and the video--you really should be able to map out your own wiring-diagram. Best of luck with the trike project! Be safe!

[@rayzapata2630]

I would like one to if possible.

[@alireza071]

nice one bro tjis is what i was looking for aftet all research thank u can u kindly advice what switch relay shall i use as the one in ur video is very small to other 12v car relay for 12v brake light 12v already feeded to the light and relay just works as a switch witch it powers on with 5v from ignition am i right.... do i have to search part for 5v relay? advice pls

[@SaberToothBicycle]

I've updated the video-description with a more details. I hope that can answer your questions!

[@antoinemark543]

Hi man, could you tell me please how you assembled the power input? I am mounting a ebike but I do not know nothing about eletronic

[@SaberToothBicycle]

Hi, @antoinemark543 I'd like to help, but I'm not sure I understand your question. Listen--if you do not know anything about electronics, you will probably struggle with this. Show the video to somebody who does understand basic-electricity, and they'll be able to help you!

[@nelutataru4662]

Hello. I bought an Yume M11 electric scooter. The scooter came with the rear light broken (the red diffuser ) and because was mounted on the rear fender after a while broke completely. Yume sent me a replacement but now I have no brake light. I changed the connectors between them and the led's are working either 2 either 3 from 5 total which 3 I presume should be for the brake light. I understood that the controller has a low and a high brake wire. Is the high 12V? I will mount a separate brake light but I see other connectors with only 1 wire. It means the wire is only +? If yes which one. And the ground is common with other ground wire? Please help me. [Smile]

[@SaberToothBicycle]

Hi there! I'm sorry you're having trouble with the brake-lights on your electric-scooter. The relay-modification in the video here is meant for electric-bicycles which didn't already come with brake-lights. Since your scooter originally came with working brake-lights, it'll be best if you can get them working again--as original. I suggest you inquire at your local scooter (or e-scooter) dealership. If they haven't an in-house service-department, maybe they can still recommend a technician who can assist you. Best of luck!

[@radicalgames9256]

Hey! When I connect my positive and negative break cables from my controller to my relay, the controller sees it as if I'm breaking. Any idea why? Could you post a diagram for your wiring?

[@SaberToothBicycle]

I cannot be certain, but it sounds like your brake-cables from the controller might be reversed in polarity. The "Low Brake" circuit has a very-low-current positive signal, and the circuit is designed to be completed via your brake-handles to negative/ground. With my modification, the relay's coil is what becomes "triggered" by the brake-handles, and the relay's contacts close that "low brake" circuit (and the other set of contacts are for your brake-light). Because I'm not a monetized member of KZbin, I am prevented from being able to post a link in either the description, or the comments, so I'm unable to post a wiring diagram. However, I do have that image (with the arrows and labels) posted over at the electricbike dot com e-bike forum. That forum is actually a great place to find help. If you go there, and enter the rest of the following, after the "m" in com--you can find the image (remove any spaces): Forward-slash forum forward-slash filedata forward-slash fetch?id=107768&d=1591984287 I hope that isn't too much of a puzzle! Good luck with your project, RadicalGames!

[@radicalgames9256]

@@SaberToothBicycle I just had a look at your diagram. So when the handles are pressed, the positive wire closes, and the coil turns on. Then what happens? Is it that the circuit for the break wires that goes in the controller opens (so the controller senses you've hit the breaks) circuit for the break lights closes, so the rear light turns on?

[@SaberToothBicycle]

@@radicalgames9256 The coil circuit is closed by the brake handles. The Low Brake circuit is a sensing-circuit. One wire is Positive, and is always on, the other one is Negative (ground). The Low Brake Circuit is completed (closed) by one set of contacts, your (personally-chosen) brake light circuit is closed with the other set of contacts. Be patient with yourself. It is not a lot of wires. I have faith in your abilities. If you find your frustrations persist, I will be here. But if those frustrations mount up, you also may wish to try to find somebody near to you, who can help. Best of luck, RadicalGames!

[@radicalgames9256]

@@SaberToothBicycle I just wanted to let you know I've figured it out thanks to your video, comments, and diagram! Thanks a lot you absolute king! 👑

[@SaberToothBicycle]

@@radicalgames9256 That is fantastic! I'm glad to hear that you got it working! All the best, RadicalGames. Ride safe!

[@historyunderbeneath]

i want to add a brake light to my stealth bomber bike. i have a 72v li-ion battery with a 12v DC/DC step down fitted. would i need the use a 12v omron g6b-2214p-us relay from the step down unit. or find a 5v wire if there is one. coming from the speed controller.

[@SaberToothBicycle]

You'll want to use the same relay (or an equivalent). The voltage source for the relay's coil (as described) is the sensor-power circuit. Regardless of system voltage, the sensor-circuits are 5vdc. Similarly to what I did in the video, you could tap into the Throttle Signal circuit, or your PAS (pedal-rotation sensor) circuit. You will not be able to power the relay however, from the Low Brake sensor signal circuit. There's not enough current available in that circuit to power the relay's coil--and that's the reason most others in the past abandoned the idea of using a relay. If you are uncertain how to proceed, find an e-bike technician to set it up for you. That stepdown transformer will be helpful for providing power to your brake light; as you'll be able to choose any automotive or motorcycle lamp assembly you wish (as I mentioned--LED lamps are a good choice--because their current-draw will be well within the relay's limitations). Best of luck with your project!

[@historyunderbeneath]

@@SaberToothBicycle Hi again Tim and thank you for replying back to me. the thumb nail picture that you have for this video. would it be possible please if you could send me a larger sized viewable photo of it. thanks in advance. also. i have just done a voltage test from the PAS cable from the speed controller and it's voltage is showing up as 4.26v is that normal/ok to work with the 5v rely?

[@SaberToothBicycle]

​@@historyunderbeneath Yes, that PAS circuit should be an adequate power-source for the relay's coil. Regarding that thumbnail, I've been wanting to get a viewable version up with this video. I keep trying to figure out KZbin Studio. It shouldn't be hard to insert that still-image into the video--to sit on screen for a few seconds. Viewers could pause, take a screenshot--whatever. Because it's a technical video--that would be very helpful, but so far I haven't been able to figure out how to do that. I'll keep trying.

[@historyunderbeneath]

@@SaberToothBicycle if i give you my email address would you send it to me please.

[@SaberToothBicycle]

@History_Under_Beneath For privacy reasons, I'll ask that you please don't share your email address in the comments. It's nothing personal--but it just seems for the best. Anyways. Because I'm not a monetized member of KZbin, I am prevented from being able to post a link in either the description, or the comments. However, I do have that image posted over at the electricbike dot com e-bike forum. That's actually a great place to find help--just saying. If you go there, and enter the rest of the following, after the "m" in com--you can find the image (remove any spaces): Forward-slash forum forward-slash filedata forward-slash fetch?id=107768&d=1591984287 I hope that isn't too much of a puzzle! Good luck!

[@shadoworkz123]

Hi. I want to apply this to my Ebike. I'm using 52v and 12v tail light so it will have a step down converter. My question is if I can use that relay to switch on and off my tail light? I ask because the relay is 5v only, I'm confused.

[@SaberToothBicycle]

Yes you can! I have got a combo taillight/brakelight (aftermarket, LED, meant for a scooter or the like). The relay lights up the brakelight independent of the taillight in my case. But yeah. Absolutely. It will work! What I have is basically the same as you. 48V system, 12V lighting (via transformer). As shown in the clip, any voltage brake light will work. If you listen to me carefully, all the instructions you need are in the clip. It does go by fast, I realize... Maybe I should add some subtitles. Read the other comments too. I have described where to find that picture with the relay. If you still are struggling to understand, ask an e-bike technician in your local area for help. Let them watch the clip. Pay them for their time generously. They'll be a helpful ally for you!

[@shadoworkz123]

@@SaberToothBicycle Thank you for a fast reply.

[@SaberToothBicycle]

@@shadoworkz123 you're welcome, and good luck with your project!

[@shadoworkz123]

@@SaberToothBicycle Hi again. I just want to thank you for this. I works for me. Great help.

[@SaberToothBicycle]

@@shadoworkz123 Oh, fantastic! Glad to hear another success-story! All the best, John-- take care, and ride safe!

[@freakenstein1984]

Do you think you could build a full motorcycle lighting system horn . Turn signals. Beake lights. Head lights. All led . kit runing off a 12v rechargeable battery.

[@SaberToothBicycle]

Yes. I have all that on my bakfiets, along with fog lights, and connection for a trailer with complete lighting. All the switches and components were readily available off the shelf items. If I can? You could too.

[@freakenstein1984]

@@SaberToothBicycle I have a razor mx650. If you look it up I want a full street legal light and horn system for it but running off a 12v rechargeable battery. I don't know anything about wiring

[@SaberToothBicycle]

@@freakenstein1984 If you don't understand wiring, you're going to struggle. I suggest you find a local technician to help you. If you have a scooter/motorbike shop they should have both the knowledge and access to the parts you'll need. Yes, that will cost you more. But alas, you cannot enjoy the "do-it-yourself discount" if you can't "do-it-yourself". Best of luck with your project!

[@SigmaMale9901]

I'm running a 60v li-ion batt. I'm adding a DC/DC step down to 12v to power my headlights blinkers and brake lights. Now can I use my regeneration brake wires on my brake handle to activate my brake light? If so that seems to simple compared to what I was really expecting.

[@SaberToothBicycle]

Yes. Exactly as outlined in the video--assuming you use that exact relay. And yes--it's a lot simpler than you'd expect. I'm running a 48VDC battery, using a buck-converter (48VDC --> 12VDC) to power my lighting (and radio/USB outlet/etc). All e-bike systems, regardless of voltage--will use +5VDC for their controller's (+) sensor voltage-source. The +5VDC wire going to either throttle or PAS sensor can be spliced into. The controller's +5VDC passes through the brake-handle switches' circuits--to power the relay's coil, then back to (-) negative/ground/black-wire. One set of contacts is used to complete the controller's "Low Brake" circuit. The other set of contacts is used to complete the power-circuit to the brake-light (any voltage). In the video, you can see the relay I've set up for the demo is equipped with connectors. I've configured it basically like a plug-and-play module--something you could drop right into an existing system--without having to cut and splice any wires. You can see I've soldered on all the appropriate standard e-bike brake-handle connectors (male and female) to make that possible--but "plug-and-play" was mostly just for the sake of clarity--for the sake of the demonstration video. You could do the same--make it modular if you'd like to--but obviously all those little connectors aren't really needed. All the connections could just be soldered directly. But keep a careful eye on your e-bike brake-handles' wiring-connections--you won't want them in series; but in parallel--so either (or both) handles triggers the relay. Sorry for the late response. Best of luck!

[@SigmaMale9901]

@@SaberToothBicycle nah your good with the time. I'm still waiting on parts. The info exceeds my expectations Some of the best I've found. Easy to follow. Kinda made me feel stupid and frustrated after I'd realized how simple the whole ordeal is. Thanks man keep up the great work helped alot.

[@SaberToothBicycle]

​@@SigmaMale9901 Thanks for the kind words. Don't feel frustrated--and certainly not foolish. I've been on one of the big e-bike forums for a long time, and I've seen seen many postings by many other bright people struggling with various very complicated attempts to make brake-lights work for their e-bikes. Motion-sensors, separate switches, one brake-handle for the brake-lights, the other for the motors' shut-off function, and various other "accidents waiting to happen". I just felt there must be an easier way... There was. Having figured it out, I wanted to share it!

[@SigmaMale9901]

@@SaberToothBicycle very helpful information I'm building mine from frame up in my livingroom. My first go at it. Seems to be coming along piece by piece. Couple snags here and there. Thank you again.

[@alireza071]

@@SaberToothBicycle i didnt get the first bid +and - from throttle, is + of throttle goes to the brake sensor and - of throttle go to relay so when brake active they power up the relay? then 12v in my case already connected to the rear brake so when the relay activated the light comes on

[@alireza071]

in details u mentioned the relay is a 6pin, then at the end u mentioned pin 7 and 8 so is the relay has 6pin or 8pin pls in video it looks like 6 pin but what about pin 7 and 8pls

[@SaberToothBicycle]

Relays come in various configurations. The Omron relay I used is available in various versions, some of which use eight pins--some of which use fewer pins. All the relays in the series, have their pin-positions numbered in the same way--one through eight. So, the relay I selected does not have pins in the positions numbered 3 and 6. That's why there's no mention of those two pins in my description. Hopefully this makes sense to you! If you need more clarification, I suggest you try to search for the Omron G6B-2214P-US 5 VDC relay's specification sheet online. It is available for download. I cannot post links here, because I'm just a "basic" KZbin member (since I do not pay Google for the extra services, I am not allowed link-posting). But you can find and download the specs in pdf format from many sources. I found the data-sheet at the Conrad website, but it is available from the Mauser website also (for examples). Best of luck to you!

[@LDem-xj7ex]

Your explanation is clear, but I noticed that if you connected you brake lever "through" the relay and through the throttle wires, you then lost the brake cut-off function on that brake side......I was trying to avoid that, in a way both brake handles cut the motor AND turn the brake light AND are turned on-off via the light steering switch (light/horn).......Unfortunately, if i use the brake handle 5v signal, it doent work because the signal is so weak that the 5v relay doesn't activate at all, and the cut-off function still goes through the relay and cuts the motor, but the relay remains dead........I cant figure out how to do what I want.......

[@SaberToothBicycle]

Thanks for your reply. I don't "lose" any brake-cut-off functionality at all with my modification. I've only used one brake-handle in the video, but there's room for both. Squeezing either, or both brake-handles activates the brake-light, and cuts the motor off (and in my case, it triggers the controller to begin regenerative-braking). So I must admit I do not fully comprehend what you're trying to describe. However--I do have an answer to that problem you are having--with the weakness of the brake-sensing circuit. That's 100% normal, and is in fact, the exact reason why I wired the relay to work the way it does! You have simply discovered for yourself just how essentially ineffective that "low-brake" signal is--for anything but deactivating the motor-controller. That's it's job--and it really is totally useless for accomplishing anything else. That's why in my modification, the relay simply devotes a set of contacts to close that circuit instead of the brake-handles. That circuit plays no other role--because it really truly and honestly--just can't. Again--perhaps I misunderstood--but just for clarity's sake: I would not recommend throwing away the safety-benefits of brake-lights during daylight hours by setting them up to be switched on and off with your headlights. If you have only one light--you can opt to keep that for your "tail-light" and add another brighter one for your brake-light circuit. As I said in the video--you can choose anything you like--for your brake-light. For my tail-light, I used an aftermarket LED lamp, 12V DC (for a motorcycle/moped/scooter), with three wires: One is obviously ground (-), the second wire is a (+) "tail-light" wire that lights it up regular-brightness; and the third is a (+) "brake-light" wire that lights the lamp up extra-brightly. The way I wired it up for myself, that "taillight" function goes on and off with my headlights-switch, while the brighter "brake-light" function (via my relay's contacts) is always active (or... to be more precise--it's always active whenever my power-switch is turned-on). If you have a basic understanding of electricity though, you can consider your desired functionality, select a relay (maybe more than one) which allows you to have all the appropriate contacts for your purposes, and then take the time to carefully wire it all up accordingly. Best of luck with your project! Be safe!

[@Gwatts78]

Bink

[@garyrendano4717]

just another thing to fail on an e-bike