Another “Mobility Scooter again” thread

Discussion in 'General Electronics Chat' started by katy, May 18, 2014.

  1. katy

    Thread Starter New Member

    May 17, 2014
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    Another newbie here (retired industrial electrician) trying to fix a mobility scooter for a friend. (retired machinist)

    Scooter is a BladeZ DKS200 Sport, 24 volt. Basic machine, hand throttle control, squeeze lever right for forward, squeeze lever left for reverse, another pot w/knob to control max speed, only accessory is a small beeper. Looks like a well built machine.

    Apparently they were discontinued a few years ago and no support is available. Have the operators manual but it doesn't say didley other than how to turn it on etc.
    Web search for info, wiring diagram, schematic, etc came up blank. Did find a few posts a few years old, people looking for the same throttle pot.

    The owner/friend had problem w/the throttle, would hesitate, go, not go, etc. He suspected the throttle pot, removed it and took the pot apart, saw carbon traces(?) on the pot so ordered a new one. Installed new pot and says it worked once and then quit.
    Pot is 5K linear and checks out.
    Number of the original pot (which he doesn't have anymore) is supposedly RVQ24YNO3-8A 21S B502 Cosmos
    Replacement pot is a different brand.
    Batteries (2X12volt) are fully charged. Motor and main controller are at the back under a cover.
    I discovered that when throttle is pushed to full reverse there was a click near the drive that turned out to be the electric brake release operating.
    The throttle lever only moves the pot a small amount from centre in either direction, (approximately 22º), so I removed the lever and found that when I turned the pot manually in either direction from centre the brake release would operate then the motor would start to turn, the more I turned the pot the faster the motor would go.
    For full speed forward the pot had to be turned aprox 135º from centre. Reverse doesn’t go as fast.
    Don’t understand why the original pot only had to turn a small amount to increase speed to max and on the replacement pot it has to turn a lot more, which cannot happen w/the throttle lever on.

    Any suggestions or help would be greatly appreciated.
    Ken in Alberta
     
  2. inwo

    Well-Known Member

    Nov 7, 2013
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    Didn't understand the problem first read.:p

    What is the voltage from high side to low side? (pot)

    From low side reference, what voltage on wiper max and minimum position?

    What is max voltage when manually turning uninstalled pot for max speed?
     
  3. katy

    Thread Starter New Member

    May 17, 2014
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    4.12v

    Min = 0v, Max = 4.087v

    Don't understand what you mean by "uninstalled pot".

    With pot in place, connected and the throttle control lever not in place, the max speed is when the "forward" side of the pot reaches 3.75v.

    When switch is on and pot is in neutral (centre) position voltage from wiper to either end is 4.05v, voltage at wiper is 23.5v +

    Hope this makes sense.
     
  4. MrChips

    Moderator

    Oct 2, 2009
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    Can you make sure that the throttle pot is actually a potentiometer?
    Some throttle controllers are optical devices that vary light intensity on to an optical sensor.

    Edit: Sorry, I reread your post and you have already identified it as a pot.
     
  5. MrChips

    Moderator

    Oct 2, 2009
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    Let me see if I get this right.

    The 5k pot works and gives you full speed control to max speed.
    The throttle handle mechanism prevents the pot from turning the full amount.

    Can you post pictures of the pot and the throttle?
     
  6. katy

    Thread Starter New Member

    May 17, 2014
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    That's correct.

    I don't really know if it's supposed to be a pot or some other device that resembles a pot. The one that's on there now is definitely a pot.
    The owner doesn't have the original device. He assures me that the # RVQ24YNO3-8A 21S B502 Cosmos was on the original. But methinks ???

    Will get some pics.
     
  7. katy

    Thread Starter New Member

    May 17, 2014
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    Here's some pics, hope this works and that they're not too big.
    Control panel, pot, pot w/lever handle in place.
     
  8. inwo

    Well-Known Member

    Nov 7, 2013
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    It really doesn't.:confused:

    If you have 4v from wiper to either end, there should be 8v across pot end to end.

    The 23v must be from some other reference. Only interested in the pot readings. To figure a way to get full V swing from partial movement.
     
  9. inwo

    Well-Known Member

    Nov 7, 2013
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    As that seems correct, one solution is to bias the adjustment toward forward.

    In other words, adjust the mechanics to get full speed forward, and live with whatever low speed reverse gives you.
     
  10. inwo

    Well-Known Member

    Nov 7, 2013
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    Another solution is to add a limit switch that activates in full speed position.

    NO. contact from high side to wiper.:)
     
  11. inwo

    Well-Known Member

    Nov 7, 2013
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    And yet another...................:D
    A center tap should cut travel in half if you just use one side.

    [​IMG]
     
  12. katy

    Thread Starter New Member

    May 17, 2014
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    The more I think about it the more I wonder if the pot is the wrong device. Maybe it should be something else? All I know of the device is what I was told by the owner and posted previously.

    Is there such a thing as an optical or some other device that would look like a pot and only have a small amount of travel? I'm not up on modern electronics.
     
  13. MrChips

    Moderator

    Oct 2, 2009
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    Where is the throttle control?
    Normally I would expect it to be a twist handle on the handle bar.
    I am not familiar with mobility scooters.
     
  14. inwo

    Well-Known Member

    Nov 7, 2013
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    Kids scooters use hall effect sensors.

    I still don't understand your voltage readings.
    "When switch is on and pot is in neutral (centre) position voltage from wiper to either end is 4.05v, voltage at wiper is 23.5v +"

    End to end should be 8.1v then:confused:
    The 23.5 I don't get at all.

    Hall effect throttles I've seen go from 0-5 volts I believe.

    ps.
    The ones I have run on 4-6vdc. Have about 90 degrees of travel.
     
    Last edited: May 20, 2014
  15. inwo

    Well-Known Member

    Nov 7, 2013
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    What about the switch or center tapped pot? No good?

    A 50 degree pot................
    http://www.robotmarketplace.com/products/4QD-POT-050.html

    Or the correct throttle pot. (possibly)
    http://www.monsterscooterparts.com/throttle-pot-pride-victory-sc1600-sc1700.html


    [​IMG]

    http://www.monsterscooterparts.com/...t-92821211804676&query=throttle pot&x=15&y=15
     
    Last edited: May 20, 2014
  16. katy

    Thread Starter New Member

    May 17, 2014
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    Mr. Chips,

    Throttle control is a "wig-wag" handle on the steering handles, looks similar to what you posted in your last post. You can see it in the 3rd pic I posted.

    I looked at monsterscooter parts and they don't list a throttle control for the BladeZ DKS 200 Sport scooter. I see a lot of the throttle controls listed use a 5K pot.

    The scooter looks similar to the Pride Go-Go, http://www.pridemobility.com/gogo/index.asp

    That 50º pot looks promising, if it's available in a 5K version. I'll have to research research that.

    inwo,

    I don't understand the readings either, but that's what they are.
    Because the normal position of the pot is w/the wiper in centre I assume the feed is to the centre and it feeds out from either end to wherever it goes.
    The 3 wires from the pot plug in to a small (2"x3") PC board with a few components on it, an LED, 3 resistors, 2 caps, 3 diodes, a 24v relay & a transistor. Resistors and diodes check out. The back of the board is covered with a very, very sticky black foam pad, almost impossible to remove.
    There is a 7 conductor cable (actually 8 cond, but only seven used) that plugs into this board and goes to the main controller, "down under" beside the drive motor. Where this cable connects, hard wired, to the main controller it is covered with a large glob of hardened glue or epoxy so I cannot see where the connections go.
    The main controller has a gazillion components on it, mostly surface mount.

    I'm not familiar w/the center tap you mentioned. (A center tap should cut travel in half if you just use one side.) Can you elaborate? Or provide a link.

    I'm going away for about a week so will be out of touch until I get back.
    FWIW, I don't have a laptop.
    Ken in Alberta
     
  17. MrChips

    Moderator

    Oct 2, 2009
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    5kΩ pot with 50° rotation seems to be the commonly used pot for this application.

    I suspect a 10kΩ should also work.
     
  18. katy

    Thread Starter New Member

    May 17, 2014
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    Update, I finally located what methinks is the correct pot, 5K Ω, with 45º rotation. Couldn't find a 5K 50º one. Kinda pricey at $31 & $19 shipping, but as long as it works. Couple of weeks for it to get here and then I'll do another update, hopefully a happy one.

    BTW, what are you guys using to get the ohmega symbol? I searched and came up with: alt 234, alt 937, alt 8486 and alt 269, but none of these worked for me.
    Have Windows XP, using MS word.
    Had to copy and paste. Ω
     
    Last edited: Jun 1, 2014
  19. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,553
    2,375
    The pop up on the RH side when you post a message/reply.
    Go 'advanced', not 'Post Quick Reply'.
    Max.
     
  20. katy

    Thread Starter New Member

    May 17, 2014
    9
    0
    Got it, thanks.
     
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