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About gwhy

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    E-sherco E-bmx

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  1. what are the dimensions of the motor they use. i.e diameter and length. engine braking is a function of the controller, not because is the motor is brushless
  2. the armature should just pull out of the other bearing, be careful that you dont damage the brushes if the whole bearing comes out of the housing still attached to the shaft as the bearing will hit the brushes, try just tapping the mounting ears of the end cap while holding the armature in the air.. but dont go mad with the hammer :-).
  3. the tamers are no longer available.. sorry. I have posted a few other options that you can experiment with listed with in this oset thread.
  4. If it were me I would just replace the plug and socket with a much better suited ( off the shelf ) Plug and socket. i.e xt60's
  5. with the charger connected to the battery the voltage should come down to more like 48v and will only get upto the (aprox 55v) when nearly or fully charged. measure your battery voltage with it disconnected from everything first, if it flat and the battery is still ok then this will be around 47v ( if its lower then you prob have a faulty battery ) a fully charged battery should be around 52v (off the charger )( the aprox cutoff voltage when your battery is being charged will be around 56v) basically the charger voltage should drop down to more like what the battery voltage is when you test it when not connected to anything, if it dont drop down when you plug the charger in then the most prob reason is either faulty battery or a bad/no connection from charger to battery.
  6. a bigger front sprocket or smaller rear sprocket will actually put more stress on the motor/controller and battery.
  7. there should be no slack in the chain on a oset as the chain stays at a fixed length , you need a tensioner on a petrol bike (engine in the main frame ) because the distance changes as the suspension goes up and down
  8. I look at a clutch on a petrol bike is torque control and the throttle on a petrol bike is speed control and when riding a petrol bike you mix the 2 to achieve nice smooth riding.. the power control sets the maximum current limit ( i think depending on the oset controller ) if that control was used as a clutch function on the handlebars then this may solve the problem but then you will also need to move the rear brake on the handlebars to a foot brake.
  9. I would like to try to throw some light on this subject if I can, There are 2 types of motor control ( controller ) there is speed control and torque control and some controller mix these 2 to blend these types of control. The current going through the motor generates the torque and the voltage regulates the velocity ( speed ) . With a speed type controller the max Current that is allowed through the motor is fixed at a maximum level at any throttle position i.e 100A , so for example when you twist the throttle this send a voltage to the motor proportional to the throttle position ( so the more voltage the faster the wheel rotate ) which sounds fine but the problem with that is very slow throttle control is difficult.. think of this extreme example of a speed based control at very slow speeds: you are approaching some large slippery stones at a very slow speed ( maybe 1/3 throttle position ) and the approach is flat, at that moment the Current will only be high enough to produce enough torque to maintain momentum on the flat as you come to the first stone the front wheel hits the stone and decreases you momentum but not enough so that you come to a stand still and the bike still moves forward, when the rear wheel hits the slippery stone this then decreases the momentum even more by which time the front wheel have also dropped into a ridge and if you did not increase the torque the bike will become stationary so you twist the throttle a little more to try a push the front wheel through the ridge , you may have to increase the throttle much more than needed to achieve this ( because the voltage to motor generates the needed current ( torque) you may have to increase the throttle position to 2/3 just to keep up the bikes momentum to overcome the ridge ), all is good upto this point but as soon as the front wheel comes out of the ridge the current then drops but you still have a 2/3 throttle speed demand at the rear and this can then break traction on a slippery surface and so the cycle continues. There are good torque controllers and there are bad ones, the kelly controllers allow you to mix the 2 types through the programming software and can achieve pretty good results, but ideally the 2 systems should be independent of each other unless you also setup electronic motor breaking ( normally done through the throttle). Torque based only control would be comparable to riding a petrol bike at full throttle all the time and using the clutch to regulate speed, which is fine when there is a load on the bike i.e uphill or over stuff, but riding down a hill velocity will just keep increasing unless you also shut the throttle off , and this is where a blend of torque a speed is needed to maintain good control of the bike. I think this is why a lot of people have problems with the osets ( electric bikes in general) for very slow control, a electric bike needs quite a bit of torque (on a speed based controller this can mean you need to twist the throttle 1/2 of its travel before it generates enough current at the motor) to start moving but the instant the rear wheel starts spinning the torque ( current ) drops but speed is still dialled in to 1/2 throttle (speed), some people learn to compensate others dont this results in very jerky throttle control at very slow speeds.
  10. a 10ah battery with a 10c continuous discharge will be fine, a 20ah 10c would be much better.. the 10ah 10c rating = 100A cont discharge and the 20ah 10c rating = 200A cont discharge.. but all hobbyking batterys that I have played with they all have over spec'ed C ratings and a 10c rated battery normally comes out as a 2c cont rating .. they can peek a lot higher so this is not so much of a problem on a small bike so rule of thumb would be at least 10c cont with 15c peak ( spec'ed) for a 10ah battery, I still have a 10c 16ah 48v battery that i used on a daily basis ( complete charge and discharge cycle every day , 5 days a week for 3 months ) often pulling 80A+ at certain parts of my journey for maybe 30seconds at a time , towards the end of the 3 months the capacity drop did start to become noticeable but I still have them and are now around about only 8ah but this was after around 3.5 years of major abuse. they have around 200 charge/discharge cycles total.
  11. So thats a total of around 34v for the 4 batterys, did the bike cut out at that voltage? . that is pretty low and to be honest I would expect it to cutout, I have a recollection that the lvc is around 36v for the oset 48v controllers
  12. Out of intrest and information, did oset say what the lvc is on the controller ?
  13. Yes it can be more complicated than that, but unlikely. Check all connectors and make sure that they are clean and well connected tot he wire at the crimp ,even at the battery's, The relay is also inline to the controller so this is another place to look at the connections, but it could be the relay itself ( high resistance contacts in the relay).
  14. ok, so no bms. one thing you could check is the lvc ( low voltage cutoff ) built into the controller, if the bikes voltage drops to below the lvc limit of the controller the bike will cut out. The battery voltage drops under load i.e going up hills Im not 100% sure what the lvc is on the oset controller but I think its around 38v, you will need away on logging the voltage under load to fault find this problem, or if you can borrow a set of batterys to see if the problem goes away. It may not be the batterys at fault but could be just a poor ( high resistance ) connection between the battery and the controller, you may be able to feel for this by feeling the temprature of the connections when this fault happens as if it is really bad then connections will be much hotter than normal.
  15. What batterys are you using ?.. it sounds like it could be a bms problem.
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