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Thread: Should you have a mechanical, manual pack disconnect?

              
   
   
  1. #1
    Senior Member Ted Dillard's Avatar
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    Should you have a mechanical, manual pack disconnect?

    Yes.

    Power in Flux: The History of Electric Motorcycles
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  3. #2
    Senior Member Ted Dillard's Avatar
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    Pro:

    - Easy, fast disconnect for working on the bike. (Depending on where your battery terminals are, it's not often too convenient to disconnect the pack using them. Also, if your terminals are sealed or whatever, disconnect there gives you wear and tear.

    - Redundant safety. Sure, your contactor is supposed to take care of this for you, as well as fuses, and even two contactors, but then again, I'm supposed to be rich and good lookin'.

    - Cheap, takes up no space, is really easy to wire in. $40. Game over.


    Con:

    I'm not seeing one.
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  4. #3
    Empulse R #24 frodus's Avatar
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    I say Sure. Brammo had a battery plug that could be disconnected while working on the bike.

    For my Kart, I'm using SB350's for the disconnect between pack and the contactor. PLEASE, PLEASE fuse before this if you possibly can.

    I won't be using a manual switch or e-stop that passes current. I'll have a BRB (Big red button) that interrupts the KSI on the controller I use, to disengage the contactor and stop the controller from electrically commutating.
    Last edited by frodus; 4 Weeks Ago at 0803.

  5. #4
    Senior Member Functional Artist's Avatar
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    Yup!

    I even go "dual purpose" & use resettable circuit breakers for the fuse & main cut-off switch for all of the go karts that I design/make.

    I also use a circuit breaker as a fuse & main cut-off switch, mounted right on the battery pack, on my bike.

    But, mine is a low powered (48V) art bike. (I was originally offended by "low powered art bike" but, it's kinda true & I seem like it now)

  6. #5
    Senior Member Stevo's Avatar
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    I've got my chicken curry simmering in it's coconut milk now, so I finally have time to add my 2 cents worth.
    I'm going to be the forward thinking, lone dissenter here and disagree with all of you!
    I say MAYBE, depending on system design and components used. We've come a looooooong way in 10 years! Yes,
    I've used the mechanical cutoffs in the past, but.....
    The affordability, quality, and availability of today's components are truly amazing.
    If you want to compare a shutoff switch to a pitcock valve on an ice motorcycle, that's a good start. My 1996 Honda VFR has a mechanical shutoff on the bottom of the fuel tank, like most ICE motorcycles, but you can't get to it! Its only there for removing the fuel tank. There is, however, a diaphragm on-off valve that is controlled by a vacuum line. Hmmmmm....a lot like a contactor switch!
    Did I say "Switch"? Yes! A contactor is a switch. And today's contactors are way more robust of a switch than any mechanical switch available.
    Tesla uses 2 contactors to disconnect the battery packs on their mass produced cars. No mechanical switch.

    Thanks for the hijacking of my build thread! And thanks for starting this thread here, where it belongs!!
    Current rides: '96 Honda Ohlins VFR, '03 Cannondale C440R, '03 Cannondale Cannibal, '06 Yamaha 450 Wolverine 4x4
    Current builds: WORX.VOR.v3.2

  7. #6
    Senior Member Ted Dillard's Avatar
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    mmmm. Chicken Curry. I'll be right over.

    Funny you should mention petcocks. I have never, ever, had a manual petcock leak, and I've ridden for almost as long as Richard. I can't say the same thing about the vacuum shutoffs.

    Ultimately it comes down to your trust the technology, your trust of your own design and build skills, the risk, and the price (in all senses of the word) of eliminating that risk. That's where your petcock example breaks down.

    Also, as an aside, what's the deal with the sanctimony of build threads these days? In the past, a build thread was to look at what someone was putting together, give them a chance to ask questions about what they needed help with, some constructive critique, stuff like that. You know... discussion. It's not like we spun off into talking about the Red Sox or anything -it is all pertinent to your build... and a fine build it is.
    Last edited by Ted Dillard; 4 Weeks Ago at 1234.
    Power in Flux: The History of Electric Motorcycles
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  8. #7
    Senior Member Stevo's Avatar
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    Lol...
    I'll tell ya what Ted, if you read in my obituary that I was electrocuted by my diy emc , you can be the first to say "I told ya so!"

    Sent from my Pixel 2 using Tapatalk
    Current rides: '96 Honda Ohlins VFR, '03 Cannondale C440R, '03 Cannondale Cannibal, '06 Yamaha 450 Wolverine 4x4
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  9. #8
    Senior Member Ted Dillard's Avatar
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    bdb3355eaa78e1913c74e7631d691892.jpg

    I'd rather hear you say, "GEE TED, YOU MAY BE RIGHT!" but like I said, I have a 24 year old son. I have realistic expectations. You did however say "maybe" so I'll take it.
    Last edited by Ted Dillard; 4 Weeks Ago at 1243.
    Power in Flux: The History of Electric Motorcycles
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  10. #9
    Senior Member Stevo's Avatar
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    I'm glad you saw that because I have used them in the past and I do use one on my fishing kayak! I actually use a Jackson plug, a Gigavac switch, a tethered kill switch controlling an LEV200 contactor, AND an Eaton waterproof circuit breaker for extra redundancy due to salt water being such a great conductor.

    I will also add that I am by no means an expert here. I was just joining the discussion/debate and adding my opinion. I do have several years of engineering education under my belt, mostly metallurgical, and completed a TV repair course. I know about degaussing old crt tubes.... the capacitance of which will surely shock the shit right out of you, even after being unplugged and turned off for some time. I'm a Rad Tech for career... I chose a different life path way back that coincided more with my life's values of helping others and making life easier for other people. I still have lots to learn but I'm pretty confident in my latest build and the technology that is available to us today. We live in truly exciting times, and changes and advances are coming upon us faster than ever before at any point in history. I am an optimist and prefer to be. My choice!
    Sent from my Pixel 2 using Tapatalk
    Last edited by Stevo; 4 Weeks Ago at 0041.
    Current rides: '96 Honda Ohlins VFR, '03 Cannondale C440R, '03 Cannondale Cannibal, '06 Yamaha 450 Wolverine 4x4
    Current builds: WORX.VOR.v3.2

  11. #10
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    I have an estop with a overcurrent magnetic blowout on the negative side and an LEV200 on the positive side. I will say that when I have accidentally had the bike go into uncontrolled acceleration when messing with settings that e-stop sure is more handy then turning the key to off. Second it is easier to store the bike for the winter. Hit the estop and disconnect the balance connectors and I'm done.

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