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Thread: Questions about proper accessory components for a 60V system

              
   
   
  1. #21
    Empulse R #24 frodus's Avatar
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    Quote Originally Posted by Functional Artist View Post
    All due respect, but I think these systems are a little different than the systems your used to working with too.

    It may be like that on them thousand dollar controllers. (they may have a DC to DC voltage reducer built in, for the signals, but I don't think so)

    All of signals on these small Chinese controllers are "pack voltage".

    On the 24VDC YC31 speed controller, all of the outputs are 24VDC. http://www.diygokarts.com/vb/showthread.php?t=38841
    So, for the brake light I wired (2) 12VDC bulbs in series.

    On my 48VDC Torsk kart all of the out puts are 48VDC. http://www.diygokarts.com/vb/showthread.php?t=38905
    For the brake light on this one I could have wired (4) bulbs in series, but instead I "rigged up" a voltage divider.
    Partially correct. I've done anything from 24V e-bike controllers, to Kelly controllers, to Curtis and Sevcon controllers all the way up to Rinehart PM100DXR's. It's just been a long time since I've seen a controller like this one, designed so poorly.

    I did look at that controller. There's some schematics online where people reverse engineered them, and yes, they're 60V as soon as you turn things on (except throttle input), which is a very poor design. They have a 12V and 5V regulator inside there, they're just not using them for anything other than internal circuitry.

    Key switch is 60V
    Brake light output is 60V
    Indicator light is 60V
    Brake switch looks like 60V
    Throttle is 5V on pin 1

    In the end, as Ted said: You get what you pay for.
    Last edited by frodus; 16 November 2018 at 1205.
    Travis

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  3. #22
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    Quote Originally Posted by frodus View Post
    Partially correct. I've done anything from 24V e-bike controllers, to Kelly controllers, to Curtis and Sevcon controllers all the way up to Rinehart PM100DXR's. It's just been a long time since I've seen a controller like this one, designed so poorly.

    I did look at that controller. There's some schematics online where people reverse engineered them, and yes, they're 60V as soon as you turn things on (except throttle input), which is a very poor design. They have a 12V and 5V regulator inside there, they're just not using them for anything other than internal circuitry.

    Key switch is 60V
    Brake light output is 60V
    Indicator light is 60V
    Brake switch looks like 60V
    Throttle is 5V on pin 1

    In the end, as Ted said: You get what you pay for.
    Oh OK, from the answers you gave, you didn't seem familiar with these controllers.

    Most of the small speed controllers I've dealt with (on scooters pit bikes & such) are set up like this, I guess their all designed poorly.

    Thanks for the confirmation, I haven't actually hooked it up yet & just assumed everything was "pack voltage".

    I took a quick peek inside.
    Attached Images Attached Images

  4. #23
    Senior Member Ted Dillard's Avatar
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    mmmmm.

    Rinehart.

    Power in Flux: The History of Electric Motorcycles
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  6. #24
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    I have found several switches rated for 72VDC +, but they seem way "over built" to control simple "signal" circuits.

    Yes, these circuits are "pack voltage" (60VDC) but, they should not carry much (if any) "actual" current.

    This speed controller should only draw maybe ~250mA
    ...& I don't think there should not be much of an amp draw from the reverse & 3-speed circuits at all.

    Only the "big power" wires will ever carry the high amperage. (up to 35A)

    The thick red (+) & thick black (-) "Power" / "Battery" wires, "carry the current" from the battery pack to the speed controller
    ...& the thick blue, thick yellow & thick green "Motor" / "Power" wires, "carry the current" from the speed controller to the motor.

    So, "thinkin' it thru" & "outside of the box" even, I was thinking, what is the "worst case scenario" if any one of these switches ever failed?

    1.) On/off switch:
    If it failed in the "open" position, the speed controller would not turn on.
    If it failed in the "closed" position, the speed controller would not turn off.

    2.) Reverse switch:
    If it failed in the "open" position, the speed controller would not activate the reverse function.
    If it failed in the "closed" position, the speed controller would be stuck in reverse mode.

    3.) 3-Speed switch:
    If it failed in the "open" position, the speed controller would operate (in default mode) at med speed.
    If it failed in the "closed" position, the speed controller would be stuck in either low or high speed.

    I (personally) don't see where, if any of these switches failed, it would or could cause an unsafe or "runaway" situation, but to be sure, I figured It may be a good idea to get some input from electronic experts.

    So, I asked these questions on an electronics forum.


    Here is what they said:

    "If the control switches are really only operating 'functions' and not controlling the main power feed (in or out) directly then they can be 'any' switch that provides the required function.

    Only the 'power' and 'motor' cables carry high currents.

    Use an isolator switch and a fuse for the power (from the battery) and connect the motor directly to the control unit. You could even use a large contactor to switch the power on/off (defaulting to off when power is removed) which would be easier to source than a switch at those ratings. The contactor itself would be controlled by a small switch. This would even allow you to fit an emergency stop button (big red mushroom) in the event of problems or even act as a 'dead mans switch' by virtue of a cord-operated switch to shut off power if the driver falls out etc.

    The remaining control voltages are just that - control - and you can use any switch (such as those rated at 12V, 125V or 250V etc) as they carry minimal current."

    https://www.electronicspoint.com/thr.../#post-1780035

  7. #25
    Senior Member Ted Dillard's Avatar
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    So, I run into a mutual friend of a High School friend of mine. I ask, hey, how's Bob doing? My friend said, well, lemmee tellya. If Bob spent half the energy he spends trying to scam his way out of work, actually working, he'd be doing fine.

    Your post starts with asking proper components for a 60V system. It seems to me that if you started with a good quality controller with an acceptable design, you'd put a heck of a lot less work into building the system, you'd have a far more reliable system, and you'd learn how to do it the "right" way. The only thing I'd add to that is, thinking "out of the box" is something that brings us all to this crazy "building electric motorcycles" stuff in the first place, but thinking out of the box with electrical practices and components has been, in my experience, a waste of time, money, and risk.

    I started out with an Alltrax PMDC controller, the 7245, which handles up to 90V. The thing has been called the greatest unsung hero of electric vehicle DIY builders by a couple of friends. It just works. It's a tank. I use a Vicor DC/DC to step down to my 12V system, which runs my contactor. All the switches on my bars are 12V, safe as milk. I have one bigass switch to cut my pack voltage. It's never failed, I don't expect it will, and as I've said, I've gone through a box of those cheap Chinese controllers. I did some EV repairs for a couple of startup companies that needed field service people, and ultimately ended up just replacing Chinese controllers, because that's the only part of their systems that failed.

    They're junk, and they're unreliable, and ultimately they're a waste of time. In my opinion.

    I'm not saying you're scamming anything, and I get you're trying to get bang for your buck, but on anything you're going to ride past about a mile away from your tool box, I pretty strongly feel that creative thinking here is false economy.
    Last edited by Ted Dillard; 18 November 2018 at 1549.
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  8. #26
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    "You can't do that!"

    "I think I just did" ...Tony Soprano


    I have been repurposing things & using stuff for alternative purposes for years & years.
    ...just gotta "think it thru" & if still not sure do more research. (or do some testing)

    I've built at least (10) electric karts using these "low cost" Chinese controllers.
    Used ones, new ones, brushed, brushless & have NEVER burned out or had a controller fail. (knock on wood)

    I have over heated some motors (& they failed) & melted some connections (loose wires cause fires) but, never a controller.

    The main problem on most of the "broken" electric scooters that I've bought over the years (other than dead batteries) was the fuse holder (or the wires going to it) got hot & melted/seperated.


    When I first started on the DIY go kart forum I was told:

    "You not supposed to use water pipe to make go kart frames"
    ...but, "I guess, didn't get the memo" & had already made several karts out of regular old hardware store water pipe. (with no problems...ever)

    "Electric go karts are just kids toys" (big power wheels)
    ...till they kept seeing me zipping around 20MPH+. (& not having to deal with carb, choke or clutch issues...ever)

    "You can't use 12V 12AH SLA's, you have to use "big" batteries, anything smaller than 12V 20AH is a waste of time".
    ...till I show where I can & do "ride hard" for ~45 min. time after time.

    Now, they don't "tell me" much anymore, they just watch & learn.


    I am NOT tryin' to be cocky. I know that "I don't know hardly anything", but I do, do lots & lots of research (Ha, Ha, I said do, do) & testing.

    Ya can't always wait for others to answer the question for you.

    Sometimes (most times) ya gotta pretend your a Marine:
    ...Lead by example, adapt, overcome &/or "figure it the "F" out"

    * I ask questions, do research, think about it, gather info (sometimes build & test) & then, share the info/results.

  9. #27
    Senior Member Ted Dillard's Avatar
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    Just trying to give you the benefit of my own experience, there Sparky.

    I have a drag-racing belt sander they told me couldn't deliver any more power than what the power cord could handle (16A @ 120V) until I powered it with Turnigy lipo and just used the power to switch the contactor. I get it, I get you're trying to explore the limits, but there's some stuff that I feel I'm better off going with conventional solutions. You asked.

    I will point out, though, non-street legal 20mph carts are a little different than street-legal 100mph+ motorcycles that can leave you stranded 50 miles from home, and, again, as you asked for "proper" components. There they are, for you to work with or ignore.

    And yes, that last post? Comes off as pretty ****ing cocky. My suspicion is that, rather than "watching and learning", those folks have given up trying to help you. (Once again, I find myself posting on your thread to caution other readers, not to necessarily try to help you out... just sayin'.)
    Last edited by Ted Dillard; 19 November 2018 at 0347.
    Power in Flux: The History of Electric Motorcycles
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  10. #28
    Empulse R #24 frodus's Avatar
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    If you don't want our advice, why ask for it?
    This is my last comment on the topic.

    I'm a degreed Senior Electrical Engineer and design systems all day long using rated components for the application. I'd never use a 12V switch for something switching 24V, 60V or 120VDC. I'd use one rated for the voltage it is switching. There are reasons to use rated switches rather than 12V ones for switching higher voltage. Arcing causes pitting of the contacts. They WILL eventually fail and stop working, and you'll replace them and repeat the cycle. That's the trade-off of using a switch that isn't rated to switch 60V.

    Will it work? Absolutely.
    How many times will it work?
    How long will it work? That's hard to tell. The arcing is affected by a combination of current AND voltage. Sure its a low current application (signal wires only), but the voltage is higher than the switch is designed for. If the voltage is higher than the contacts have been designed for and rated by the manufacturer, it is not guaranteed to function the full expected life of the product.
    Travis

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  12. #29
    Senior Member Ted Dillard's Avatar
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    "I've built at least (10) electric karts using these "low cost" Chinese controllers.
    Used ones, new ones, brushed, brushless & have NEVER burned out or had a controller fail."


    You've also never built anything that's over 60V, amirite?
    Power in Flux: The History of Electric Motorcycles
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  13. #30
    Senior Member Ted Dillard's Avatar
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    ah, I see you got some good advice over on DIY Electric Car*: https://www.diyelectriccar.com/forum...9&postcount=12

    I'd take it, if I were you.




    *still up to your forum cross-posting habits as well, I see.
    Last edited by Ted Dillard; 20 November 2018 at 1507.
    Power in Flux: The History of Electric Motorcycles
    www.powerinflux.com

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