Power in Flux
Likes Likes:  1
Page 2 of 2 FirstFirst 12
Results 11 to 20 of 20

Thread: Step by Step Circuit Diagram Buildup

              
   
   
  1. #11
    Senior Member
    Join Date
    Feb 2011
    Posts
    520
    Post Thanks / Like
    The enable line draws <0.1mA You can use any key switch you want directly from the enable.

    Pack the connector to the DC/DC and your keyswitch with diaelectric grease or use a pull-up resistor, or a drip of water in the wrong spot can turn on the Sevcon DC/DC

  2. #12
    Member bugeyebug's Avatar
    Join Date
    Apr 2012
    Posts
    32
    Post Thanks / Like
    My EE friend agrees that I *can* use the OEM key switch to handle full pack voltage, but he said he'd avoid it if possible. Here's his preferred method. The 12V battery is used to power the contactor that enables the DC-DC system. Then 12V is used to turn on the bigger contractor with the smaller one. It feels a bit like overkill to me, but I have to admit that it keeps the OEM switches operating at their rated voltages. As usual, comments and/or suggestions are greatly welcome.

  3. #13
    Empulse R #24 frodus's Avatar
    Join Date
    Aug 2010
    Location
    Portland, OR
    Posts
    2,673
    Post Thanks / Like

    My Social Networking

    Follow frodus On Twitter
    do you have the SW200 yet? Is the coil pack voltage?

    It's seems a bit overkill to run a contactor and relay, but if you have the contactor already, use it. If not, consider getting one with a 12V coil on it, and it'd eliminate the little relay.
    Travis

  4. #14
    Member bugeyebug's Avatar
    Join Date
    Apr 2012
    Posts
    32
    Post Thanks / Like
    Yes, I have the SW200 (it came with my controller and motor)... but I still have to buy the smaller contactor to operate it per my diagram. Therefore, maybe you're right; i.e., I should think about getting a contactor that has 12V operation, but can handle the big voltage on the other side. This would simplify things.

    Does anyone have a preferred part number or model of contactor that takes 12V input, but can handle the big voltage on the controlled side? Where's a good place to shop for such animals?

    thanks again. you guys rock.

  5. #15
    Seņor Member podolefsky's Avatar
    Join Date
    Oct 2010
    Location
    Boulder, CO
    Posts
    3,890
    Post Thanks / Like
    Quote Originally Posted by bugeyebug View Post
    My EE friend agrees that I *can* use the OEM key switch to handle full pack voltage, but he said he'd avoid it if possible. Here's his preferred method. The 12V battery is used to power the contactor that enables the DC-DC system. Then 12V is used to turn on the bigger contractor with the smaller one. It feels a bit like overkill to me, but I have to admit that it keeps the OEM switches operating at their rated voltages. As usual, comments and/or suggestions are greatly welcome.
    You can use the 12V keyswitch for the enable without a problem, because the enable input has such a low current limit. The place you run into trouble is when there isn't a current limit - the keyswitch *will* work, for a while. Eventually arcing will burn out the contacts. With the low current, you won't get any arcing and you'll be fine.

    Keyswitch to DC-DC enable, then a 12V contactor coil run from the DC-DC would be simplest.
    - Noah Podolefsky -
    The GSX-E

  6. #16
    Seņor Member podolefsky's Avatar
    Join Date
    Oct 2010
    Location
    Boulder, CO
    Posts
    3,890
    Post Thanks / Like
    Quote Originally Posted by bugeyebug View Post
    Yes, I have the SW200 (it came with my controller and motor)... but I still have to buy the smaller contactor to operate it per my diagram. Therefore, maybe you're right; i.e., I should think about getting a contactor that has 12V operation, but can handle the big voltage on the other side. This would simplify things.

    Does anyone have a preferred part number or model of contactor that takes 12V input, but can handle the big voltage on the controlled side? Where's a good place to shop for such animals?

    thanks again. you guys rock.

    LEV200 or EV200. Both are great, totally sealed, come in 12V versions. The EV200 has a coil "economizer" that uses less power, and it's nice and small. Either will work fine from your DC-DC.
    - Noah Podolefsky -
    The GSX-E

  7. #17
    Empulse R #24 frodus's Avatar
    Join Date
    Aug 2010
    Location
    Portland, OR
    Posts
    2,673
    Post Thanks / Like

    My Social Networking

    Follow frodus On Twitter
    The smaller one is usually called a relay not contactor since it's low current. High current relays are called contactors.

    What is the coil voltage of your sw200?

    Lots of people use the ev200 and they're cheap on eBay and go up to 900vdc. And they're sealed.
    Travis

  8. #18
    Member bugeyebug's Avatar
    Join Date
    Apr 2012
    Posts
    32
    Post Thanks / Like
    Okay, how does this look?


    A few things to note:
    • I'm starting to get more comfortable with the idea of running high voltage/low current through the OEM key switch. I also like the idea of eliminating the relay to activate the main contactor. What this means, however, is I now have to buy a different main contactor than the one currently in my possession... ah, but so be it. I can sell the existing SW200 unit on eBay or the forums, and recoup some of my money. Said another way, I'm more interested in doing this all correctly (and simplify things) than skimping on a few bucks.
    • I also like the idea of not carrying around a heavy, bulky 12V aux battery. Space is limited on the bike as it is, and if I can do away with this unit, I'll be quite happy.
    • I think I need an on/off enable switch on the 12V side of the DC-DC converter to ensure the aux equipment can be turned off in the event the converter fails in the On configuration. This is unlikely to happen, but a switch seems cheap insurance to add.
    • I've included a master manually-operated disconnect switch on the negative side of the battery bank. This will be used primarily when I'm doing maintenance on the bike (i.e., to isolate the battery), but will also be located in a prominent front-and-center location where I can operate it in the event of an emergency. Is this reasonable?

    Comments/Suggestions/Criticisms/Rotten-Tomatoes are welcome...

  9. #19
    Seņor Member podolefsky's Avatar
    Join Date
    Oct 2010
    Location
    Boulder, CO
    Posts
    3,890
    Post Thanks / Like
    Looks good. Very clean diagram. Nice job.

    Move the main fuse to the other side of the charger connection, so that there is nothing between B+ and the fuse.

    You can (probably should) use more like a 10A fuse on the HV side of the DC-DC. If it's 20A output at 12V, that's going to be about 3A at 76V input side.

    Not sure you need a fuse just for the contactor coil. I guess it can't hurt, but seems unnecessary.

    Having the disconnect switch is a good idea. Just know that it's only rated to break 800A. In most situations that should be fine, but if you have a controller fault that shorts the battery to motor, you could see well over 1000A. In that case, the LEV200 is going to be your only safety valve.
    - Noah Podolefsky -
    The GSX-E

  10. #20
    Empulse R #24 frodus's Avatar
    Join Date
    Aug 2010
    Location
    Portland, OR
    Posts
    2,673
    Post Thanks / Like

    My Social Networking

    Follow frodus On Twitter
    The charger should have it's own fuse unless the manual specs otherwise.

    In this situation, I'd 100% go with an EV200 (the one with economizer) as it uses less current to hold and it's a bit smaller.

    The output of the DC-DC doesn't really need to be switched. An ON/OFF on the enable line to the DC-DC will turn it off completely. Turning off the output doesn't turn off the DC-DC, it'll still idle and use power.

    +1 on the lower rating fuse on the input to the DC-DC, it's way too high and the "low current" fuse on the input is redundant (unless the DC-DC manual specs it).

    Your fuse on the Contactor is fine, and you should really have a fuse for all loads (kind of like the fuse block on a motorcycle)... but since you fuse before it, you may be OK without it.

    If you DO use that shutoff as emergency, don't expect it to work more than ONCE under load. It WILL be damaged.
    Travis

Page 2 of 2 FirstFirst 12

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •