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Master power switch for E-bike ideas

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  • eccerr0r
    replied
    Re: Master power switch for E-bike ideas

    PLA and incandescent bulbs of any type do NOT mix.

    And no, don't use those high wattage halogens, you want low wattage bulbs for their resistance, like a 4W night light bulb... or less. Enough to charge the capacitors, not enough to run the bike in any capacity. Unless the intent is to give a thief a false sense of hope?

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  • sam_sam_sam
    replied
    Re: Master power switch for E-bike ideas

    Yes and less current than 500 watt would be
    If you have an old light fixture that uses this type of bulb then you just need to figure out how to use the holders together so it will work maybe make it on a 3 D printer
    Last edited by sam_sam_sam; 12-12-2021, 07:34 AM.

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  • Dannyx
    replied
    Re: Master power switch for E-bike ideas

    Originally posted by stj View Post
    bulk? use a linear halogen tube - they are like a short pencil.
    Might work. Would still need a holder for it....or I could go ghetto and solder to it directly I already grabbed a 50w resistor from Ali for like 2 bucks which has lugs on the end already. Like I said: no rush, since it's going to be another 4-5 months until I can go for a ride on this thing

    Originally posted by sam_sam_sam View Post
    Yeah but I would use a 250 watt version not the 500 watt version
    Because 250w = higher resistance ?
    Last edited by Dannyx; 12-12-2021, 06:44 AM.

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  • sam_sam_sam
    replied
    Re: Master power switch for E-bike ideas

    Yeah but I would use a 250 watt version not the 500 watt version

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  • stj
    replied
    Re: Master power switch for E-bike ideas

    bulk? use a linear halogen tube - they are like a short pencil.

    Leave a comment:


  • Dannyx
    replied
    Re: Master power switch for E-bike ideas

    Originally posted by eccerr0r View Post
    Could stick a 120V incandescent bulb there instead of a resistor...still not going anywhere fast, and really cheap.
    This is actually a good idea and I thought of it myself a while ago, though the resistance would be all over the place. It's bulkier too, so space is a bit of an issue. Not sure what the "idle" power consumption would be (with the FET off), because the bulb would be in series with the controller box all the time, so long as the battery's connected, but the resistance is probably high enough the power consumption would also be negligible, even with a stone-cold filament.

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  • eccerr0r
    replied
    Re: Master power switch for E-bike ideas

    I don't think you really can "take off" with the resistor regardless. Worst case it'll run really slowly and the resistor will burn out... Put an appropriately sized 100 ohm resistor there, you can't even get one twentieth of a horsepower out of the motor - that's not going anywhere fast.

    Could stick a 120V incandescent bulb there instead of a resistor...still not going anywhere fast, and really cheap.

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  • Dannyx
    replied
    Re: Master power switch for E-bike ideas

    Naah - too basic

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  • stj
    replied
    Re: Master power switch for E-bike ideas

    just put a fucking 2pole switch on it and stop over-complicating things!

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  • Dannyx
    replied
    Re: Master power switch for E-bike ideas

    Just remembered this bike has a "power enable" pin in the cable which connects the display to the controller. I could tap into that to act as my power on signal to turn the FET on after the caps have already charged through the resistor idea. That way, it becomes physically impossible to take off on JUST the resistor(s) by mistake. Problem solved
    Last edited by Dannyx; 12-11-2021, 03:29 PM.

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  • Dannyx
    replied
    Re: Master power switch for E-bike ideas

    Glad to see people find the topic funny around here

    I went with 100v version after all. Should have it somewhere the following week.

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  • kaboom
    replied
    Re: Master power switch for E-bike ideas

    Originally posted by stj View Post
    just use a contactor to short the battery and blow them to hell
    /jk
    Watch it there, Kreosan!
    /thread

    Leave a comment:


  • eccerr0r
    replied
    Re: Master power switch for E-bike ideas

    Originally posted by Dannyx View Post
    I was thinking of a low-ish value, like 100ohms, which WOULD allow the display to fire up, making someone think it's ready to go, but the whole system would collapse as soon as the motor tries to kick in. It would also burn a ton of power...like 50w or so. Not sure if practical in the long run...
    Or add more capacitors and they can watch the screen fade away as they discharge... or sooner if they try to engage the motor.

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  • stj
    replied
    Re: Master power switch for E-bike ideas

    just use a contactor to short the battery and blow them to hell
    /jk

    Leave a comment:


  • Dannyx
    replied
    Re: Master power switch for E-bike ideas

    Originally posted by eccerr0r View Post
    You can't ride the bike with a 1K resistor there though you probably should go 100K or so, just to cheapen things.
    I was thinking of a low-ish value, like 100ohms, which WOULD allow the display to fire up, making someone think it's ready to go, but the whole system would collapse as soon as the motor tries to kick in. It would also burn a ton of power...like 50w or so. Not sure if practical in the long run...

    Leave a comment:


  • eccerr0r
    replied
    Re: Master power switch for E-bike ideas

    You can't ride the bike with a 1K resistor there though you probably should go 100K or so, just to cheapen things.

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  • Dannyx
    replied
    Re: Master power switch for E-bike ideas

    Originally posted by eccerr0r View Post
    Now that's a really low ESR capacitor... Then again it is an ideal capacitor, and ideal capacitors have 0 ESR.
    Can't remember if at that point I tried using "generic" caps or some of the "real" models the program offers...

    I may be overthinking it, but that FET is one expensive part like I said Seems I can't smooth out that spike any more, at least not without exaggerating the startup time AND possibly driving the zener out of regulation because its current would be too LOW at that point.

    Another thing I tried was placing a resistor across the FET (D-S) so it charges the caps FIRST and THEN the FET shunts it. I was happy with the simulation results, but then it became obvious that there'd be nothing would stop me (or someone else) from attempting to ride the bike with the switch in the 'off' position, so all the power going through that resistor and I can't think of a way to keep this from happening, unless I complicate the circuit even more and use that slow rise time as a switch for a secondary command, like cutting power to the control panel of the bike....dunno....

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  • eccerr0r
    replied
    Re: Master power switch for E-bike ideas

    Now that's a really low ESR capacitor... Then again it is an ideal capacitor, and ideal capacitors have 0 ESR.

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  • Dannyx
    replied
    Re: Master power switch for E-bike ideas

    Out of curiosity, I tried hooking up the caps directly to the power supply in LTSpice and of course the current went off the chart to like 350a at startup, so I'd say around 1.4a is reasonable there
    Last edited by Dannyx; 12-10-2021, 11:23 AM.

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  • eccerr0r
    replied
    Re: Master power switch for E-bike ideas

    depends on your default model. Looks reasonable though, you should expand out the waveform.
    TBH the "real" waveform is what to expect, and not much you can do about it, though you can slow it down even more by messing with the rc delay but it'll slow turn on time even more...

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