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    Keyed-switch no longer is now a 12V DC circuit, and both the power for the main fuse-panel, and the motors' power-switch circuits are now controlled via the keyed-switch by relays.

    The halogen headlamps' circuitry, are also fed via signal-legs from the headlight-switch, then relays for the higher-current load.

    The little battery which pretends to be a car-battery, and will maintain the radio's memory whenever the main 48V battery is removed--also connects for recharging--via a relay.

    Initially, when I purchased my Cyclone kit from Taiwan, I also ordered the 10A buck-converter to go with it. Obviously, it didn't take long to realize that the accesories and lights that I wished to use were going to need more than 10A worth of power--so I bought a 30A buck-converter (from Uncle Ali)--to do the job.

    I've been actually using both DC-DC converters for some time, but having two has proven to be super-helpful in terms of setting up these relay-circuits.

    When trying to feed a switched relay-circuit, if it happens to share a switched-leg with a positive-lead coming from the same voltage-source--once that relay has been switched on, it'll bypass it's own switch-leg, and backfeed its coil via its voltage source. Once turned on, the switch leg won't disconnect. Now--that's handy--if that's what you're going for. A simple "momentary" switch can easily activate a relay-powered circuit--and it'll stay on until the power-source is totally switched off...

    But that's not what I wanted.

    My situation is made more complex--because the battery doesn't work like a car battery at all--the system can share many "automotive" components, but there's no alternator for recharging--and the battery itself is operating at four-times "automotive" voltage. Needless to say, the circuitry in my machine has to be carefully done--to prevent any unwanted current-flow.

    I needed the radio's little backup-battery isolated from the electrical-system----only feeding the radio's memory via its "always-on" wire. But I also needed it to be able to connect too--because as soon as the power-switch is thrown on, I wanted the radio fed from the 30A buck-transformer--while I also wanted that battery connected so it could then begin to recharge. A relay was obviously going to be needed, in order to facilitate that.

    But to prevent back-feeding, I not only had to protect that recharge-relay's trigger-coil from the main-30A transformer's circuitry backfeeding it--I also had to prevent that coil from being backfed via its own little backup-battery.

    It was a puzzle. Until I was able to figure it out, the radio's backup-battery was giving me issues. As soon as the charge-circuit was closed, it just wouldn't reopen--and then the battery was back-feeding the whole electrical panel.

    The solution--to prevent the back-feed issues--was ultimately simple. I decided to use the small 10A buck-transformer to power the keyed-switch's circuit--which in turn powers all three power-system relays' coils.

    This eliminated any possible paths for those coils to become back-fed--and the system is working perfectly.


    Now, the Battery Disconnect Switch can remain on, allowing the charger to charge, perhaps to power the yet-to-come alarm-system---but now the key controls basically everything else: Lights, horn, signals, UBS-charging-outlets, motors, radio--all that switches off with the key.

    Last phase of this will be to completely replace the wiring (again) this time, it'll be a proper wiring-harness--still set up for maximum-modularity, but hopefully also for a lot more tidiness.

    More to follow...
    Last edited by tklop; 04-18-2020, 11:55 PM.


      Just got back from a couple hours' worth of night-riding... Beautiful weather--lots of stars out...

      I saw a lot of resting cows, and waterfowl, and I saw an owl, and a lot of bats--and not too many other human beings at all.

      I had the time to adjust the headlights' beams, and do some other fine-tuning.

      I'm still waiting on my temp gauge, so I'm commited to being careful, but within that frame-of-mind, I did a little bit of experimenting tonight while monitoring the BMS via its Bluetooth App. I did indeed do some "peak-power" testing--but it was all in brief intervals, and the amperage-consumption of the DD's remained precisely within their expected (and advertised) parameters. Suring, the motors' vendor, gave me instructions on just how long I could exceed the "max-temp"... I took note--but it's been awhile, and I cannot remember the exact numbers... It's someplace further up this project-thread--last page, I think... Anyways, the DD motors aren't supposed to exceed some certain temperature (something like 200 or 220 Celsisus maybe), for any longer than some particular multiple-number-of-minutes (therefore at least two)... Because I'm worried about cooking them, I've never operated the motors at peak-power for anywhere near two-minutes, since the moment of their installation--including tonight. Peak-power applications have been more like a few seconds--never even a minute. Though unreliable data-wise (I do know heat-buildup won't quickly transfer to the motors' housings) --even so, the motors' housings still have yet to feel even skin-temperature warm to the touch... In other words, I am pretty sure I've not damaged them (yet).

      Some data: Peak-consumption (either under hard acceleration, or in "High Speed Mode") seems to be right around 65A; with 25A going to the Cyclone mid-drive, and 40A split between the two DD's.

      At my peak-speed in "Normal" mode (on the 3-speed switch), consumption holds steady at around 45A--with still 25A going to the Cyclone--I think they're pushing less, as they're approaching their own top-speed--but in any case, only 10A each is going to the two DD's

      Using PAS mode (PAS level 5--default), consumption hovers around 25A split between all three motors (assuming I'm only "ghost-pedaling" --obviously if I'm actually helping, that consumption will drop).

      Remembering I've got 114AH real-world non-exaggerated battery-capacity to work with, that gives me some ideas of speed vs. range, with my current config.

      Anyways... Off to sleep. More to follow, undoubtedly.
      Last edited by tklop; 04-20-2020, 04:00 PM.


      • calfee20
        calfee20 commented
        Editing a comment
        200 - 220 Celsius is to high 130C should be considered max. Grin's cycle analyst is preprogramed to shutdown at 130C. I was having intermittent power outage on one of my bikes and it turned out to be a bad wire in the temp sensor circuit. When it went open circuit the cycle analyst thought the temp was 700+ degrees so it shut everything down. My PAS is wired through the analyst but my throttle is direct to the controller so my throttle still worked and I drove home like a motorcycle.

      • tklop
        tklop commented
        Editing a comment
        Yeah--that's what sleepiness will do to one's memory... Those numbers I was guessing at were too high; more appropriate for the Fahrenheit range versus Celsius.

        It doesn't matter a bit though, because the reasoning behind considering my testing "safe" was based on not-remembering anyway. That same reasoning applies--and remains just as sound--and that would also be true if the Manufacturer's Recommendations put the limit at only 129 degrees Fahrenheit--I doubt I'll have ever exceeded that either--and certainly not for the length of time specified!

        As I thought, I did have Suring's recommendations further back in this thread:

        [copy/pasted from post #67] "...My manufacturer's advice, is to keep the motors from exceeding 120 degrees Celsius for more than 20 minutes---and in no case, to let them exceed 129 degrees Celsius. I can set that meter to flash it's little triangle at me, whenever I exceed 120 degrees Celsius--and oh, yeah--I also like that it's not going to SCREAM its warning at me; a visual notification is adequate...." [end copy/paste]

        No matter how lousy my memory was last night, I've never done any full-power operation for much longer than 20 seconds--let alone 20 minutes. I remain confident there has never been any overheating--or even any risk of it...

        But soon--hopefully--ambiguity will become a non-issue. The dual temp-meter arrived today!

        If I do find myself venturing above that 120 Celsius limit--into the "Danger Zone" between there --and that Do-Not-Exceed-Temp of 129 Celsius--well... I'm not going to set up some auto-shutdown or anything--I'm just going to have to monitor the gauge. Hopefully it'll be unusual to be operating in the "Red-Line-Temp-Range" so-to-speak, and if I am, I just have to make sure I shut it down before it goes over 20 minutes--or reaches 130 Celsius (the same shutdown-temp your Grin's CA is set for).

        Currently, if experimenting with (relatively) high-power, I'm also traveling at a pretty decent rate of speed--and the motors can therefore enjoy significant air-cooling. But if one day (as I'm planning) I do venture out on an extended camping trip, there might be a different landscape to work with. There may be long grades--perhaps even mountain passes maybe--and it is times like those, where using high-power at low-speed, or where using lots of e-braking on the way back down--where I expect the risks of overheating will be greatest.

        But now that there's going to be a gauge, that means soon there'll be some real info. I still need to figure out how to make the meter work properly with my existing built-in temp-sensors, but I don't expect that will be too difficult to figure out.

        Clearly--there'll be more to follow!
        Last edited by tklop; 04-23-2020, 10:08 AM. Reason: for clarity--and to fix some typos

      Here's a handy way to utilize all those (generally unused) tiny-size ring-terminals in the typical crip-terminal assortment, while turning those unreliable screw-type terminal-blocks, into an effective electrical-connection component:
      Last edited by tklop; 04-23-2020, 05:17 AM.


        Temp meter...

        First attempts at trying to get the dual temp-meter to read the signals from the DD motors' sensors have been unsuccessful.

        The sensor can handle various temp-ranges, but it may simply be incompatible with the type sensors in the wheels.

        Worse comes to worse, I can replace the wheels' internal sensors with the ones that came with the sensor.

        That'll involve removal and partial dissasembly. That's not a big deal, I've had both DD motors apart already, and have replaced the hall-sensors in one--so I'm more than certain I can handle the task... I just don't want to right now. My machine is up and running (reasonably), and I want to be able to enjoy it some before taking things apart again--essentially breaking it--until I can complete the needed upgrades.

        So still no temp-sensing for now, and I'll continue to handle everything with kid-gloves.

        Of course it will all have to come apart again eventually--and I will get those sensors working (or replaced.)

        More to follow--as always.
        Last edited by tklop; 04-23-2020, 10:03 AM.


        • tklop
          tklop commented
          Editing a comment
          The wheels' own temp-sensors may not work with this meter, but I'm still curious to see what other options I may yet have.

          The Cyclone Bluetooth Controllers (YK controllers) do have a temp-display in their app--but I've no clue what it is monitoring. Perhaps its' own controller-temp--that'd be handy--but if so, perhaps there's room for additional sensor-inputs. I obviously don't know--and that's the problem. I am aware that some of Cyclone-TW's motors have temp-sensors installed in them as well--but can't say I'm sure any of those motors are using the same YK controllers, or some other type. I am not afraid of opening up the controller's housing, and soldering onto the correct contact-point, if there actually happens to be one inside there somewhere... But how in the hell I'm supposed to know which it is--or where it might be hiding--is just beyond my pay-grade at this point.

          I'm sure the info exists--I'm sure somebody has "back-engineered"--mapped out the circuitry of the YK controllers... That crowd at the Endless Sphere site is a promising place to look--that site always seems to showpromise, but all my searches just revealed others' curiosities--never anyone's actual info or solutions.

          I know a lot of things are proprietary and whatnot--and that a lot of "manufacturer" specs just aren't going to be publicly available... But at the same time, I'd be more than a little amazed if there's not been at least a dozen different Cyclone users who've had reason (and expertise enough) to have opened up and rewired or reworked their Cyclone controllers at one time or another--if not fully "back-engineering" as earlier described... I'm relatively certain, there's at least a dozen or two who've gained extensive knowledge about their YK controllers by doing things like that... And of that group of expert-tinkerers, I'm sure at least a handful of them have also been Endless Sphere users--and as such, it seems surely at least one of them might've taken the time to have mapped out the circuitry somewhat thoroughly--if not extensively...

          That's a lot of assuming--yes. I know. But it still seems safe to assume all that--given the level of interest in the Cyclone, the number of years it has been around (in various stages of metamorphosis), and given the staggering number of worldwide users of the Cyclone kits...

          Yes, I do still think those assumptions are safe--but I'll be damned if I can find anything myself. I'm certain the info is there--it's just that the Endless Sphere search-engine is utter crap or something--I dunno. It's hard to really ever be sure over there. It's like going down Alice's rabbit-hole. Endless Sphere is well---just that... And a sphere is endless--can be wandered in any given heading--and in any roundabout way--and you may or may not ever actually get anywhere--but the odds are good you'll eventually end up wherever it was you started... Yes... Endless Sphere is much like that. You can search the Sphere Endless(ly) and come back right where you started--knowing nothing new, but feeling weary from the toils of the searching... A site destined to discourage...

          In fairness to Endless Sphere too--maybe it's an issue of "proprietary" info--and maybe there's legal reasons why circuit-maps can't be shared. Again--all questions and concerns well above my pay-grade. I just wanna know if I can find a way to plug in my damn temp-sensor.

          More to the point:

          I've a growing list of projects which require wheel-removal; none of which I'm feeling particularly eager to get started upon.

          1) Fender-liners. I need to install metal sheeting between my nice new fenders and the box, to help protect the wood. To this task, there's an added subtask--to replace the lower support-bolts at the center of the cargo-box (currently hidden behind each DD motor). Objective: Install eye-anchors to better improve battery tie-down methods.

          2) Temp-sensors. Apparently... Because I'm not cool enough (or smart enough) to know how to find anything on Endless Sphere, it looks as if the chance is high I'll need to install my new temp-sensors into the DD hub-motors if I want my dual temp-gauge to work.

          3) Disc-brakes. No, I'm not proud to admit it, but I'm still relying on e-braking for the front-wheels. I do need redundancy--and the longer I press my luck, the closer I'll come to the day I've got to deal with it.

          Eventually I'll get to these things...

          More to follow.
          Last edited by tklop; 4 weeks ago.

        • tklop
          tklop commented
          Editing a comment
          Another lovely thread/topic/discussion which I'm absolutely certain must exist--but I obviously cannot possibly locate over there (or here for that matter)--is just what's possible, in terms of using the itsy-bitsy teeny-tiny brake-switch signal-leg to trigger a relay--or maybe a transistor-circuit--which in turn could be used to activate brake-lights---a way of splitting the brake-switches' signals for dual-purposes, without taking so much of the "juice" away from the sensor-circuit...

          I know that can't only be possible in my head--in fact I'd bet a hundred dollars at least a dozen people between here and Endless Sphere have tried it--but I'm unable to find anything...

          Especially over there--I swear...

          Not to beat a dead horse...


          *Thump* (horse)

          It's an Endless Sphere alright. It's like wandering the surface of a cueball... No landmarks, no map--no chance. Endless Sphere indeed.

          In their defense--and everyone else's--my own Devil's Advocate speaks his mind too: "If I'm so sure 'it's been done' --then I may as well go ahead and prove how simple it is--and do it again, on my own. Put my money where my mouth is."

          Now, now--D.A. I wasn't born yesterday--and I can read between my own lines. You make a fair point--but you don't have to call me lazy!

          Vehicle lighting serves either to help the vehicle operator to see--or to communicate with other vehicle operators. Communication? Yes. Even simple "anti-collision" lights--daytime running lights, marker lights--being easier to see; more visible to others--that in itself communicates: "I am here!" --which is obviously an essential thing to try to let other vehicle operators know--if you don't want them to crash into you...

          Turn-signals and brake-lights further communicate driver intentions--but turn-signals only work if physically separated enough from each other to be visually effective. Any silly bicycle tail-light-cluster with little arrows on its sides--will be utterly ineffective. Worse still--if it gives the hapless rider who bought it a false sense of confidence--it might even prove fatal to them. Inadequate visual separation renders such designs more harmful than helpful. An extended arm--provides an unambiguous signal (don't forget--I do live in The Netherlands--hand-signals are actually normal here).

          That's why I have have zero interest in turn-signals for my commuter-bicycle. I briefly considered handlebar-end type lights--but since those could easily become blocked by thick gloves or sleeves too (esp for traffic to your rear), I think they too may give false confidence which they clearly don't warrant. For the bicycle? Gonna stick with the arm.

          However... Brake-Lights? Totally different story. Nobody on Earth uses the "hand downward, palm facing to the rear" to indicate braking. No--most cyclists don't signal anything at all--they just plain stop. Pay attention--or you'll rear-end somebody.

          But brake-lights do work--even here in The Netherlands--even though only a tiny number of cyclists (like me) use them here.

          They work really well, in fact. A brake-light has no "visual-separation" issues--because it goes in the middle. That also means people's eyes already know where to look--and a brake-light's message is simply impossible to misinterpret--and nearly impossible to miss.

          Brake lights are wonderfully effective communication devices for accident prevention... And yes--as my own experience as shown--brake-lights do work excellently on bicycles. On my Commuter Bike, I use a front-wheel-dynamo-powered tail-light with an automatic brake-light function. In the past, the bakfiets had the option to use those lights too, but I have no wheel-hub dynamos anymore--so it's no longer an option.

          In contrast--unlike a narrow normal bicycle, the wide-ass three-wheeled bakfiets actually does have plenty of visual separation--and so I've found having turn-signals to be actually extremely effective. Being a trike, with odd geometry, I risk significant loss of control if letting go with one hand on the bakfiets. Esp. when maneuvering (turning, etc) in traffic--I want my hands on the controls. It's just plain more to handle than when compared to the city-bike... So, to be able to communicate my turning-intentions, while still hanging onto the handlebars (ready on the brakes) with both hands--is really nice. Turn-signals are most definitely a win--on the bakfiets!

          I would like to be able to warn people that I'm stopping too. I feel when sharing the roads and bike-paths with others, more (visual) communication is better than less...

          But... To address the issue of laziness... Well, maybe there is some of that. Maybe I do want somebody else to have done the experimenting--so I can swoop in and benefit from his or her hard work... Yeah--I suppose I do have to admit there's a bit of that in there...

          And it's still true, that brake-lights are non-essential... Brake-lights aren't expected on the bike-paths; not required... So, how much I do or do not wish to invest into their system's development, installation and operation--will have to be measured against the gains--of "a nifty feature"...

          (as tklop mulls that over, he starts to sing the Tin Man theme from The Wizard of Oz... "...If I only had a brain...")
          Last edited by tklop; 3 weeks ago.

        Maybe I shouldn't use my thread as a place to keep track of things... But I've already set that precedent--so...

        Electromagnetism, UK, ca 1975, monorail technology... Another random technical nerdy clip I don't want to lose track of...


          Originally posted by tklop View Post
          Maybe I shouldn't use my thread as a place to keep track of things... But I've already set that precedent--so...

          Electromagnetism, UK, ca 1975, monorail technology... Another random technical nerdy clip I don't want to lose track of...
          I talked about brake lights back in 2016. It took me a while to find the thread. I have not tried this but I am 99% sure it will work. It seems I am always working on new bikes instead refining old ones. Right now I am working on a solar system for my travel trailer. Oh Well.

          This is the part.

          This is the thread, down toward the middle/bottom of the page.

          I know what you mean about endless sphere. There was an outrageous thread somewhere all about wiring an ebike. Let me think about it.

          Here is a photo of the batteries in my RV. They are the same chemistry as the ones in your trike.

          Click image for larger version

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          Hey be carful on your trike. I rolled mine up on it's right side a few days ago. I guess I was getting to cocky on my little sport trike.


          • tklop
            tklop commented
            Editing a comment
            I appreciate your help sleuthing calfee20 !

            AZguy 's drawings and plans looked solid (at the link from post 97 below)... I'm honestly surprised nobody has come up with a little solid-state relay/transistorized signal-amplifier/splitter -- something like he was describing. If I understood his posts--it seems like the components would cost practically nothing; the ciruitry could be made quite small--so it'd weigh only an ounce or two--and it just sounds like a really fantastic product idea--yet it still doesn't exist...

            If I could get a brake-light switching-module, triggered by the low-brake cutoff signal (as described--without interrupting that signal's normal functionality)--a module with a simple set of normally-open contacts for my own brake-light circuit--a module allowing me to choose my own lighting-system's type and voltage--that'd be just perfect...

            I would gladly pay in the neighborhood of $25 maybe even $35 shipped for such a little module--and I bet a lot of other people would too. How can it be nobody is mass-producing such a thing? Seems an absolute slam-dunk... Seems to me there should be fifteen vendors to choose from over at Uncle Ali's!

            You know what would also not surprise me--is if exactly such a switching-module actually already does exist--but it is something simply used in some totally unrealated industry or application which we e-bikers are (as yet) competely unaware of. Maybe somewhere in manufacturing, telecommunications, aerospace, or elsewhere, they're using something exactly like this already; and it's just that whoever manufactures the lovely little module is as unaware of us e-bikers and our needs--as we are of their product's existence. Perhaps all that needs to happen is for us to find one another--so that such a (hypothetical) manufacturer can be introduced to a brand new broader customer-base...

            Anyways... Dang--that spill looked unpleasant indeed... I hope you are not badly hurt. Gorgeous weather, empty streets--the ride video looked like you were really having a very nice time--at least up until that last moment.

            I will not lecture--believe me, I understand--and I do appreciate your warning--and I do indeed take heed. We pilots of three-wheeled beasts do need to keep away from "the ragged edges" of control. When things go awry, it's much like that clip. About a tenth of a second between "I've got a problem here" and "WHAM"--and obviously, that is not a lot of time to work with...

            If I'm willing to be honest with myself about it, every single close call and spill I've had on my bakfiets (to date)--has been my own fault--defensive driving failures--and I can't think of a single incident that didn't come as the direct or indirect result of excessive speed.

            The instability of any trike means our primary "emergency-manouever" is going to be hard, straight-line braking. Because sharp swerving isn't our friend, it generally means that any "scrubbing off speed" has to be done before we've entered a turn.

            I've mentioned before the emergency-braking technique of separating a turn into multiple straight-line hard-braking segments--a technique which I'd learned in a motorcycle rider training course. This technique was taught as particularly helpful when traction is compromised, but it's a technique which is especially good for us trike-users--for obvious stability reasons. Once we've found ourselves going too fast into a tightening curve--once that balance begins to shift--once the weight comes off that inside front-wheel--well, a crash is pretty-much inevitable... But even in a situation like that--when it's too late to actually avoid a crash anymore--squaring the bars and braking hard can still remain a decent option (depending upon circumstances) --I mean--if that means you'll impact the tree in front of you a little more softly--then I say, go for it. But if squaring the bars and braking hard only sends you plunging off that cliff at 20kph versus 30kph--then maybe that's actually not going to be so helpful.

            Straight-line hard braking might've saved you too--but you'd have had to stay on that pre-turn street/pathway--that is to say intentionally overrun the turn you tried to make. That might've allowed you to stop, instead of flip over... But really--from what I can tell, it's a moot point--because by the first warning of instability, it was already far too late for you to do anything about it. You just had no time... I played that clip a couple times--and yeah... Like I just described--it looks like from instability to "WHAM" was only a couple frames--maybe a tenth of a second. Who knows? Perhaps taking a different track might've helped too--it's hard to say for sure. But it looks to me, as if the only way you'd have made that turn, is if you'd managed to "scrub off" some speed beforehand.

            One thing's for certain: Were I consistently to have behaved like a properly defensive driver (esp with regards to speed), I'd have avoided trouble in each and every bakfiets scare I've had so far. Luckily, the overal numbers are low--and there have been far more close-calls than actual spills... But still...

            Yet fast is fun--and I suspect I'll continue to make judgement-errors from time to time. I ain't no saint. We're human--and we all have moments of varying degrees of irresponsibility I suppose--and accidents will happen, even though obviously nobody wants to pose a danger to themselves or to others.

            Anyway, I do hope in your incident--that damage to both rider and machine was minimal.
            Last edited by tklop; 2 weeks ago.

          • tklop
            tklop commented
            Editing a comment
            I like the looks of your RV setup. Nice clean box, got your selector-switch there I see... That's going to be nice!

          Another thread Still looking though.


            I just thought of another possibility. Someone mentioned using one brake lever for motor shut off and the other for the brake light. Not a bad idea but a little awkward. My brake cut switches have been both built in micro switches, or magnetic reed switches.

            Well why not set up both at the same time. One set does the motor cut and the other does the brake lights. You could stay away from electronics and use a miniature relay.


            • tklop
              tklop commented
              Editing a comment
              The industry could easily just put a three wire (or four wire) normally-closed DPST microswitch in the brake-handles instead--and that'd fix it too.

              I still might not want to pull full light-circuit amperage thru the switch, but it'd certainly power a relay problem-free. Same type switch; additional poles. Simplicity.

              Maybe I should open my brake-handles, and try to find a plug-and-play replacement.

              But I still think an electronic option would be nice.
              Last edited by tklop; 2 weeks ago. Reason: for clarity

            • tklop
              tklop commented
              Editing a comment
              Wait a sec... Same thought--different angle; different approach.

              They've got to make double-pole double-throw relays, right? Five or six-pins, I'm guessing?

              Anyways: Brake handles still in a parallel circuit--but now, either brake-handle closes the circuit for such a relay's coil (any voltage you specify). DPDT relay-contacts--where one set of contacts activates your brake-light; the other set of contacts closes your controller's "Low-Brake" circuit...

              A relay whose coil were powered by the controller's standard +4VDC, could switch on a tail-light circuit of any particular voltage, while simultaneously "grounding" that "Low-Brake" sensor-wire... Right?

              Seems that should work just fine...

              Or is that just too dumb simple to work?
              Last edited by tklop; 2 weeks ago.

            • calfee20
              calfee20 commented
              Editing a comment
              Oh I wasn't following you for a moment there. That is simple and it may work. I wonder how many ohms is across that coil.

            E-bike Brake Lights via a $5 relay, suggested circuitry:

            Many have suggested using a relay, but have run into obstacles. I think they've been going at the problem the hard-way. Seems most have been trying to power their relay's-coil via the super-low-current "Low-Brake" signal, and the resistance added by the coil, and other factors have made that plan prohibitively problematic... So I've decided not to do that.

            There may be reasons this might not be the ultimate relay choice--this is just a model of the correct basic configuration needed. Many other relays of the same configuration might work--but at least this one has specs which can be easily looked up. Anyways, for better or worse, here it is:

            Omron G6B-2214P-US 5 VDC

            That's a 5VDC relay, with 2 normally-open contacts, which has six-pins--and no "common" or "shared" contacts.

            And here's how I'm going to attempt to use it:

            First, I'll splice a jumper into one of the controller's (+POS)4VDC leads (from either Throttle or PAS sensor).

            Next I'll connect my e-bike brake-handles' switches--in parallel with one another. One pair of those brake-switch leads will connect to the jumper I just made, the other pair will connect to the relay's Pin 4 (on that relay, (Pins 4 and 5 are for the relay's Coil Circuit).

            When either brake-handle switch closes, it feeds that (+POS) 4VDC controller's current via Pin 4, thru the relay's coil--activating it--exiting via Pin 5, and finally on to (-NEG) (Ground)--completing the Brake Handle Switches Circuit.

            That relay has two sets of contacts which close simultaneously when the coil is activated. One set of contacts uses Pins 1 and 2, the other set uses Pins 3 and 4. Either set of contacts could be used for either purpose below--I've just chosen and labled them as they are for the sake of simplicity.

            Pins 1 and 2 will be used to connect to the controller's "Low- Brake" wires (the controller-wires that used to be connected to the e-bike brake-handle switches). Whenever the relay's coil is powered, these contacts close, completing the Low-Brake Sensing Circuit and stopping the motor. (Note: That's really the big difference. That stupid, finicky, wimpy, fragile, problematic little Low Brake signal which made others abandon the idea of using a relay--will not be used to power anything at all in this relay circuit. No--instead, it will go sailing virtually resistance-free thru a pair of closed contacts--just as it had previously done thru the switches on the handlebars--only now, those contacts will be located nice and snug in a little relay-housing)...

            Pins 7 and 8 will be used for the Brake-Light Circuit.

            Any Brake-light power-source will do, any voltage. Polarity won't really matter either--but let's say we just connect the (+POS) source-wire to Pin 7.

            When the relay's coil is powered, these contacts also will also close, allowing Pin 8 to provide the (+POS) needed to illuminate the Brake-Light, and then from there, obviously on to (-NEG) (Ground)--and the Brake Light circuit is complete.

            That particular relay can handle up to 8A nominal for its contacts--and I think most of us using LED lighting would find our brake-lights operating way, way below that.

            Now--this might just be too dumb and simple to actually work--but I hope not...

            All the best, everybody.

            Last edited by tklop; 2 weeks ago.