Electrical problem with Suede E

Discussion in 'Electric Bicycles' started by rds1228, May 23, 2010.

  1. rds1228

    rds1228 New Member

    I purchased a used Suede E for my wife and it appears to have an problem. When you attempt to ride it, there is a resistance in the front wheel that almost feels like you are riding with the front brake on sort of shudders a bit. The front wheel has been replaced (which is where the motor is ) and the battery is fully charged. The odd thing about it is that if you unplug the motor, the front wheel turns as it should. Does anyone have an idea what the issue might be or how i can diagnose the problem... I would be grateful for anyones input.. Thanks

  2. safe

    safe Active Member

    That's called "Cogging".

    It's normal... some rare motors exist that do no have "cogging" but they are not the norm.

    When the motor is running the "cogging" will seem to disappear, but if you are costing without the throttle on you will get this behavior.

    People do "regen" which is a way of capturing that drag for a useful purpose, but you need a regen controller to do that.

    Everythings fine...
  3. johnrobholmes

    johnrobholmes Member

    Sounds like the controller has a brake feature, if the issue goes away when the motor is unplugged. Does the issue also go away when the battery is removed? This would support the controller being to blame.

    The technical term for the bumpiness of a motor (magnet to steel attraction) is detent force. Cogging can also describe a rough startup due to the controller, so it may not be the best term to use without some confusion.
  4. rds1228

    rds1228 New Member

    The problem still persists ( it may even have more drag ) with the battery removed from the bike and the motor is plugged in.. It appears the only time it does not drag is to unplug the motor. Does that indicate the controller being the issue? If not, are there any other things I can try to troubleshoot it? I have a very basic amount of electical knowledge.
  5. safe

    safe Active Member

    When the motor is plugged in it creates an electrical circuit. (in a sense a battery) When the motor is unplugged then there is no electrical circuit and the movement ("Cogging" or whatever name you want to use) does not get blocked by a stored electrical charge.

    If you were to have the motor connected and watch the voltage in the lines you would see an AC wave as you rotated the motor.

    This is actually why there can be regen... any time a wire passes next to a magnet it creates a current in the wire. Conversely any time you pass current through a wire it creates a magnetic force on the magnet / wire relationship which is how we get power.

    The bottom line is that motors never spin freely unless you use something like a Halbach Array which still creates forces, but they are at least linear. The Halbach is a very unique thing that happens to be used in the Solar Racers (CSIRO) and they tend to produce the best efficiency of anything known to man.

    I'm pretty sure you are experiencing a normal motor...
  6. rds1228

    rds1228 New Member

    What we are experiencing cannot be normal... The bike litterally cannot be ridden with the motor plugged in.. The drag experienced while trying to peddle virtually make it impossible to ride. The best way I can explain it is that it feels like your riding while applying hard brake pressure to the front wheel.. Isn't the bike suppose to assist peddling rather than impede it? It appears that the main components are the motor, battery ( we have 2 ), main controller (driver board), dash panel control board and throttle. Is there a chance that any of these could be malfunctioning and if so, how can I tell which is the culprit.. Just an FYI, the front wheel which contains the motor has been replaced and did not remedy the situation.. Thanks for any advice...
  7. safe

    safe Active Member

    Maybe I need more information...

    I'm assuming that when you apply the throttle that you get forward power and the bike runs normally.

    You only experience the resistance when you let off the throttle and attempt to ride under pedal power alone.

    The resistance disappears when you disconnect the motor entirely.

    ...if these three conditions exist then you have a normal condition for a hub motor powered ebike. I have an ebike which uses a freewheel and so when I let off the throttle I can coast, but that's not very common. I've written several (long) articles about the benefits of freewheels in conjunction with ebikes so this isn't my first time thinking and discussing the topic. Basically the natural "cogging" of an electric motor when it is not being powered is a drag that is not a good feature. Some hub motors have attempted to do things like twist their internal structures (core) so as to mimimize "cogging" behavior, but it never completely goes away.

    Have you ridden other hub motor ebikes that did NOT exhibit this behavior?

    (I'm wondering what your foundation of comparision is based on)

    The easiest way to solve the problem is to just use light throttle when you want to get around slowly (by pedaling).... just enough throttle to overcome the resistance.
    Last edited: Jun 2, 2010
  8. rds1228

    rds1228 New Member

    First let me clarify that this is the first electric bike of any kind that we have owned so I have nothing to compare it to and other than the owners manual we don't know anything about the Giant Suede E. Any information you can give us on this type of bike and powering system will be a great thelp. There is no forward power when the throttle is twisted and no pedal assist either. With the motor hooked up and the power turned on the display ( Has 3 lights that indicate the amount of battery charge ) will start to blink after riding for approximately 3 to 5 minutes and then shut off which according to the manual means it has overheated.
    Last edited: Jun 2, 2010