• 11-15-2017
    1 Attachment(s)
    Want to install turn signal on my electric bike
    I'm a freshman computer science major, and I still have a lot left to learn in the realm of circuitry, but I have a decent understanding of the fundamentals.

    I have made an electric bike, and I wanted to install turn signals. The bike's battery is a 52 volt nominal, Lithium Ion battery (max 58 volts), so all my components must be able to operate on the voltage of this battery (unless I wanted to get a dc-dc converter to reduce to 12 volts, which I don't).

    I installed a 60 volt solid state flasher relay(Solid State Relays Online Ordering | PDF Datasheet | In-Stock) to control the LED turn signals, but one problem is that the flasher doesn't allow the signal lights to flash completely on and off. Instead, they flash from 100 percent brightness to about 50 percent brightness. There appears to be some electricity leaking through the flasher. When I insert my body into the circuit, my own dry skin is enough of a conductor to light the LEDs to about 40 percent brightness. (Crazy huh?) So, the LED's apparently don't need very much electricity. Therefore, I expect it might be difficult to use a resistor to reduce the system power enough to prevent the LEDs from lighting at all when the flasher is "open." My knowledge of resistors is still limited, so any suggestions on this approach are appreciated.

    Alternatively, my next idea was to use two electromechanical relays to completely break the circuit. I plan to control the energizing of the relays via my dashboard turn signal switch on my handlebars. Observe the following diagram (You'll have to forgive my circuit design skills):

    Attachment 1167621

    Are there any flaws in this idea? Improvements? Will this work, given I get the right relays? If so, can you point me to the best relay for this (must handle up to 60 volts)?

  • 11-23-2017
    Not enough info to give a definitive answer, but here's some random thoughts on the subject:
    1. What solid-state relay are you using? The link shows a page of all the solid-state relays listed by the manufacturer.
    2. MOSFET SS relays will have a leakage current (in the off state) of a few microamps, which is enough to get a bit of a glow from most modern LEDs. SCR SS relays will leak a few milliamps in the off state, which is enough for quite a bright glow.
    3. Lots of circuits out there switch LEDs with MOSFETs, and the usual fettle to eliminate off-state glow is to put a shunt resistor in parallel with the LED string. 1 kohm to 10 kohm is the usual sort of range, depending on the voltage across the LED string.
    4. What flasher unit are you using?
    5. What LEDs are you using? I'm assuming the LEDs in the OP circuit represent an LEDs+drive circuit module.

    Tieerd, PM me if you reply to this thread as the chances are I'll forget all about it. Given the spec for the flasher unit and LED modules it should be possible to rustle up something simple and reliable.
  • 06-27-2018
    Want to install turn signal on my electric bike
    Just curious, but what made you want to change the steering wheel to an aftermarket without an airbag?