Hi Everyone, I am after a little advice please from those with knowledge. I brought a cheap e bike from fleabay about 3 years ago called a "bizobike" who are no longer in this country or on ebay. It has a motor that drives the crank (like a baked bean tin if you will) , controler on the handlebars, speed sensor with a magnet on the back wheel and also a small plastic ring sensor on the other side of the crank to the chainset. The bike was garbage and I have just swapped all the electrics onto a different one but I seem to have lost the pedal assist function. Everything else works as it should so the motor and throttle/display are all good. I know a little about electronics but ebikes are a bit like dark magic to me atm, can anyone shed any light on this for me please? It has a display/controller that seem to be fitted onto the juicy bikes now
new member needs tech advise
- Thread starter twistedsanity
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Thanks for the prompt reply, when I dismantled the old.one the motor and chainset came off as one with a long drive shaft that the other pedal attached to, on the non chainset side there was an aluminium cap that screwed onto the outercasing of the shaft to keep it in place and a circular sensor that fitted onto it with two small screws then the pedal arm went on, is this what your referring to? I've just looked on eBay and it's a bang something or other unit, the only other sensor I can see is the one that picks up the magnet feed that attaches to the wheel.spokes, I'm assuming that is the speed sensor? If so the speedo works so I'm guessing that's ok. I didn't notice any magnets attached to the crank area though?
I'm not familiar with the Bafang BBS units, assuming it's that, but the common pedelec arrangement on the crank is a plastic disc with a ring of tiny magnets inserted in it. Adjacent is a Hall sensor like a tiny transistor which is cable connected to the controller and that picks up the passing magnetic fields. This is additional to back wheel speed sensing.
If the unit doesn't work that way hopefully one of our many BBS owners will come in soon and advise.
N.B. Crossed with Woosh's post.
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If the unit doesn't work that way hopefully one of our many BBS owners will come in soon and advise.
N.B. Crossed with Woosh's post.
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That sounds about right, a plastic disc adjacent to the crank that has a cable with maybe 3 pins that connects to the control unit, the plastic disc with the cables locks with 4 pins onto the aluminium screw cap that holds.the crank in place and sits adjacent to the crank cartridge with the aluminium cap inbetween, I hope that makes sense, I can't get photos until the morning
I understand what you mean now, that's different from the method I mentioned in which the disc rotates. The rotating element that signals in yours may be inside the bottom bracket and perhaps isn't close enough to the disc to signal.
I'm afraid that as I don't know these units and their bottom bracket arrangement I can't give practical help. We need someone with experience of one to come in to help, but Friday and the weekend are always quieter in the forum. If no-one comes in meanwhile I'm sure you'll get answers on Monday. Adding photos will help.
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thanks, I did check on that site but nothing like mine now, mine was a cheap Chinese mountain bike with mag wheels , I got it mainly with a view to swapping the electrics over at a later date, all the ones on their site seem to have the motors in the wheels. I cant see I missed anything when I swapped it over an I assume the plastic ring with the cables would be the pickup so thye magnets must be the other side of that rotating in the crank, is it possible to test the pickup with a meter?
it is but we need pictures so to avoid putting you on the wrong track.
first, you must retrieve the magnet ring that is behind the silver cup.
first, you must retrieve the magnet ring that is behind the silver cup.
is this ring supposed to rotate with the crank? I dont recall seeing anything so maybe its internal to the cartridge as I didnt see anything attached to the crank
I can't tell you where to look other than if your bike has pedal assist, then there is usually a magnet ring attached to the bottom bracket.
You may have lost it during the transfer. That would explain why the pedal assist does not work.
is there a brand name or serial number on the motor?
You may have lost it during the transfer. That would explain why the pedal assist does not work.
is there a brand name or serial number on the motor?
ill check for a name tomorrow , assuming the pickup is the plastic ring that fits around the crank so is static this magnet would need to rotate with the crank?
yes, that's correct but there are other designs too.
For example, the Bafang BBS has the magnet ring under the main gear cog. pedaling forward moves the cog, triggering the sensor.
For example, the Bafang BBS has the magnet ring under the main gear cog. pedaling forward moves the cog, triggering the sensor.
I see, mine is like the bafang ones on ebay, but my sensor(im assuming thats what it is) attached to the opposite side of the crank pulley not where the cog is so it couldn't trigger from the crank wheel as thats on the opposite side
thats lookd right except my motor is actually under the crank, the aluminium cover screws onto the crank cartridge to hold it securely and the plastic ring you see on the outside of it has a cable thats out of sight that goes to the controller, the plastic ring has 4 lugs that fit securely into the aluminium cap which I assume are pickups for a magnet?
your motor is fitted to a standard frame. The one in the picture is fitted to a frame designed to host the motor in a better position to avoid surface water splashes but both function in the same way.
Thanks for the information on both fault and cure, my stab in the dark guess was right about the gap.
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