FreeGo Knowledge

[RollerToaster]

I know the UK company went out of business a few years ago, but they sold a few bikes, so my assumption is there must be some people out there with relevant knowledge and experience. It would be nice to be able to tap into that.

I have two little-used FreeGo folders dating from 2016 which I am just putting back into use. Surprisingly the batteries seem to be accepting and holding a charge. But one of the bikes is suffering from motor assistance surging when pedalling. The motor cuts in as I press down the left pedal and cuts out when I start pressing down the right one. It doesn’t seem to happen in respect of the 6kmh twistgrip throttle.

I thought I had discovered the reason when I found the 12 magnet disc on the crank was disintegrating. But replacement (and checking the new disc was running true and close to the sensor) did not cure the cutting in and out. I then thought I would replace the sensor, but while I had no difficulty in removing the chain wheel, I cannot for the life of me shift the bottom bracket nut which holds the sensor bracket in position, even though I have the right tools for the job. Trouble is that while the drive side bottom bracket nut is most often a left hand thread, some bikes do have a right hand one and so I have no confidence in which direction I should apply greater force. Can anyone advise me in which direction the FreeGo folder bottom bracket nut, chain wheel side, can be loosened?

Not sure that replacing the sensor makes any sense though, given the regularity of the cutting in and out. Anyone got any suggestions what else the cause might be? Must surely be related to the pedal cadence somehow?

 

[matthewslack]

No specific knowledge, but can you jury rig a new sensor just for problem solving?

 

[RollerToaster]

Funny you should say that. I designed just such a device in my head as I was lying in bed last night, broadly a vice and an electric drill. Just have to make up a mandrel to hold the magnet disc running true. Still can’t see the logic which would cause the sensor to pulse rather than produce a steady signal, but, as you imply, worth doing if only to prove that it is not the old sensor which is at fault. Then I suppose it becomes a controller, or rather worse a motor investigation that is needed. Are those cheap e-bike system testers on Amazon any use for doing that, I wonder?

 

[Ghost1951]

This might be mad.... but is it possible that there is too much play in the bottom bracket bearing and the wobble induced by pressing hard on alternate pedals is causing the magnet disk to move away and then return to the required distance from the sensor for the signal to work? See if there is play in the bottom bracket bearings... worth a try maybe.

Alternately, is the magnet disk really running true on the shaft. Upend the bike so you can work the pedals around and look down on the magnet disk to see if it is running the same distance from the sensor as you rotate it at all points of rotation.

Hope this isn't a wild goose chase, but it won't take long to check those things.

 

[thelarkbox]

My limited understanding is that the controller will be looking for a pattern of pulses from the pas/cadence sensor, dictated by the number and spacing of magnets in the rotating disk, to initiate and continue movement.

Overtight cable ties have been found to cut into sensor wires causing issues.

If bought direct from chinese/far east suppliers via ali express/ebay.. cadence sensors are cheap(<£5) and having a spare or 2 at hand isnt a bad idea as they are vulnerable to knocks and bumps.

 

[saneagle]

I know the UK company went out of business a few years ago, but they sold a few bikes, so my assumption is there must be some people out there with relevant knowledge and experience. It would be nice to be able to tap into that.

I have two little-used FreeGo folders dating from 2016 which I am just putting back into use. Surprisingly the batteries seem to be accepting and holding a charge. But one of the bikes is suffering from motor assistance surging when pedalling. The motor cuts in as I press down the left pedal and cuts out when I start pressing down the right one. It doesn’t seem to happen in respect of the 6kmh twistgrip throttle.

I thought I had discovered the reason when I found the 12 magnet disc on the crank was disintegrating. But replacement (and checking the new disc was running true and close to the sensor) did not cure the cutting in and out. I then thought I would replace the sensor, but while I had no difficulty in removing the chain wheel, I cannot for the life of me shift the bottom bracket nut which holds the sensor bracket in position, even though I have the right tools for the job. Trouble is that while the drive side bottom bracket nut is most often a left hand thread, some bikes do have a right hand one and so I have no confidence in which direction I should apply greater force. Can anyone advise me in which direction the FreeGo folder bottom bracket nut, chain wheel side, can be loosened?

Not sure that replacing the sensor makes any sense though, given the regularity of the cutting in and out. Anyone got any suggestions what else the cause might be? Must surely be related to the pedal cadence somehow?

To get the BB out, you need a bolt and washers to hold the tool in. Then you need the longest arm you can get on the socket or spanner to turn it, then you whack it in the clockwise direction (top side forward) with a lump-hammer. I've never seen or heard of one that didn't have a left hand thread on that side.

Freegos are no different to any other Chinese ebikes, so you don't need any special information. How is the magnet disc disintegrating? Have you lost a magnet from it, in which case you can buy a replacement and glue it in, or if one fell out, make sure that you put it back the right way up.

If you replace the magnet disc, it will probably be better to replace it with one that has fewer than 12 magnets.

 

[RollerToaster]

Thank you for all those suggestions. Saneagle- the plastic disc literally fell apart into five bits as soon as I put pressure on it to clean it. I have replaced it with a new one with the same number of magnets (12). Interested to hear you suggest fewer. What is the rationale for that, please? Discs with more magnets are often advertised as providing greater smoothness of response. I had assumed - having no knowledge on the subject - that the number of discs needed might depend on what the controller was expecting to see? Why do some discs have five, some eight, and some twelve magnets? I’d appreciated being educated!

 

[saneagle]

Thank you for all those suggestions. Saneagle- the plastic disc literally fell apart into five bits as soon as I put pressure on it to clean it. I have replaced it with a new one with the same number of magnets (12). Interested to hear you suggest fewer. What is the rationale for that, please? Discs with more magnets are often advertised as providing greater smoothness of response. I had assumed - having no knowledge on the subject - that the number of discs needed might depend on what the controller was expecting to see? Why do some discs have five, some eight, and some twelve magnets? I’d appreciated being educated!

I've tried every type of magnet disc. I can't say I've ever noticed any difference between them regarding smoothness and response time. I'm guessing that anybody, who came to that conclusion, probably changed the controller at the same time, and the difference came from the controller, not the sensor.

The problem with 12 magnet discs is that there are a lot of compatibility issues. Nobody ever gets problems with 10 magnets or less. It's always 12 magnets.

The controller doesn't expect anything. It'll respond when it sees pulsing on the pedal sensor signal wire. It has its own response time to that signal programmed in with a delay to make sure it doesn't go off every time you touch the pedal.

When pedalling at a slowish 60 rpm, a 12 magnet disc takes a maximimum of 0.08 seconds for the first magnet to pass. A 5 magnet one takes 0.2 seconds, so the difference is about 0.1 second. Do you think that you could detect that difference, when it takes more than a second for your controller to respond to the pulsing?

 

[RollerToaster]

Thanks for that explanation. I may try a fewer magnet disc if my jury rig test is inconclusive. Had any experience of these cheap electronic testers I see on Amazon?

 

[saneagle]

Thanks for that explanation. I may try a fewer magnet disc if my jury rig test is inconclusive. Had any experience of these cheap electronic testers I see on Amazon?

The testers are designed to work with controller and motor cable connectors that have the 6-way white block connector and three bullets on the phase wires. For anything else, you would need to make some connector adapters.

You can do all the tests on a normal multimeter, but it takes a little longer because you can only test one thing at a time, while as you can see everything in 2 seconds with those testers. You can test the pedal sensor using the throttle test. I've just seen these for £1.84. How do they do that?

Brushless Motor Controller Tester 24V/36V/48V/60V/72V Electric Car E-Bike Scooter Hall Tester Test Device - AliExpress 1420

Smarter Shopping, Better Living! Aliexpress.com

vi.aliexpress.com

 

[RollerToaster]

How indeed?! However, for the time being I don't need to go further down this route. I tested the existing sensor and the new one by mounting the new magnet disc on to my electric drill. The new one caused the motor to run, the old one didn't. So I adapted the new sensor to fit on the old one's bracket (which I couldn't remove), put everything back together and all works just fine now. I just need to re-waterproof the hole where the wires go through the frame into the controller box, and it'll be good to go. Thanks for the helpful thoughts.

 

[saneagle]

How indeed?! However, for the time being I don't need to go further down this route. I tested the existing sensor and the new one by mounting the new magnet disc on to my electric drill. The new one caused the motor to run, the old one didn't. So I adapted the new sensor to fit on the old one's bracket (which I couldn't remove), put everything back together and all works just fine now. I just need to re-waterproof the hole where the wires go through the frame into the controller box, and it'll be good to go. Thanks for the helpful thoughts.

By all means do something about the hole where the wires go through, but do not attempt to seal the sides of the compartment. I had to repair about three bikes like yours after the owner tried to seal the compartment, but they filled up with water when it got in, but couldn't get back out, so drowned everything inside. It's designed so that any water getting in can get straight back out. I've never seen a problem in one that hadn't been sealed!

 

[RollerToaster]

Ah, good advice. I had a similar problem in my Volvo XC90, when the sun roof drainage decided to reroute itself to the inadvertent storage tank created by the double floor containing lots of the car's electronics. Solved eventually by drilling holes in the lower floor. Water didn't cease to run out of a 1 cm hole for three minutes... The electronics proved surprisingly robust to operating for some months underwater, though!