Broken my 'new to me' Wisper bike after 5 minutes

crystaljohn

Pedelecer
May 29, 2019
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Can't believe this has happened- but it did.

Yesterday I bought a Wisper 905 classic bike. It's 5 years old and on the short test ride I took behaved perfectly. It was raining heavily so I transported the bike back to my house using a towbar rack.
This morning I rode it round to my garage which is a 1/4 mile away from my house, fitted a Bungee strap onto the rear rack and also a padlock device. Rode a few hundred yards to visit a bank where I secured my new bike to the railings with the padlock device. Exited the bank, and made my way home. Whilst riding home I suddenly heard a noise and the bike seemed to grind to a halt. I dismounted and saw that the Bungee strap had got caught up in the rear hub. I pulled the 2 halfs of the strap which seemed to come away easily free and jumped back on the bike. No action from the motor.

I see that when I switch the bike on a red light blinks on and off on the battery charge indicator, and after approx 15 seconds all 6 light blink on and off on the display below which is the diagnostic display. According the the manual if all 6 lights flash at the same time this is a 'System electronics/Software failure.'

So far I have removed the cover on the frame, pulled the controller out from it's enclosure and checked the voltage going into the controller at the connector ( it's 40.6v)

My first thought is that possibly I have overloaded the motor and blown one or more of the F.E.T's.

I do know how to run a check on these, but as I am totally unfamiliar with this new to me bike I thought it would be prudent to seek advice here as maybe I have missed something obvious as to why the display is behaving like this.
any advice appreicated please.


Here is a 30 second video of the display:https://photos.google.com/share/AF1QipNN7oX7JmuXU92m-eJvu72KCQ9grehzie7R0AH6cGvSbp3r46AMcziHQ1LhWbF7ew?key=S0hKeDN1OW4zV2F3aDN6cENiaHNLOUtDSWdYbFBB
 
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vfr400

Esteemed Pedelecer
Jun 12, 2011
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Hopefully, it's something simple, like you've pulled the motor connector a bit, so it's not making good contact. It has to go all the way in until the edge of the outer reaches a line around the other side.

The mosfets only blow when you give full power via the throttle or PAS while the motor is going too slow. Whatever you do, don't try giving it full throttle until the motor is running properly.

Also, have a look at the motor cable to check that it's not damaged, especially where it comes out of the axle.
 

crystaljohn

Pedelecer
May 29, 2019
138
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Thanks for your reply vfr400.
I have taken onboard your advice about not applying full throttle until the motor is running properly.

No damage done to the motor cable , it wasn't effected in anyway by what happened, and the motor connector is securely plugged together and has been fitted in such a way at the factory with cable ties fastening it to the frame that its not likely to become loose.
 

Nealh

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Aug 7, 2014
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Did the bungee get caught up any where near where the motor cable exits the axle ?
 

Nealh

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Regarding vfr 's reply do not dismiss the motor cable connection out of hand, although held by cable ties it only needs a tug for the pins to disconnect. The final 1 - 2mm of connection can make the difference between working and not working correctly. Often the obvious can be the culprit as many have found out.
 
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crystaljohn

Pedelecer
May 29, 2019
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no the bungee was wound around the hub, nowhere near where the motor cable exits the hub, I believe somehow the Bungee got caught in the sprockets and the chain severed the Bungee, some of the cord was wrapped around the hub, but definitely nowhere near the cable, I have examined it carefully.IMG_20201014_213311.jpgIMG_20201014_213251.jpg
 

vfr400

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I can't understand why you're saying that. the motor cable is right next to the gears. How could the bungee get wrapped around the gears without touching it?
 

crystaljohn

Pedelecer
May 29, 2019
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The motor cable exits the axle on the LHS of the bike, the sprockets and chain are on the RHS of the bike.
 

Nealh

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Aug 7, 2014
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Must be an Aikema hub bike then ?
I believe they were used for a year or so.
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
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The photo show that the connector isn't in properly. You didn't listen to what we said.
Yep it is about 2mm shy of fully being connected.
 

crystaljohn

Pedelecer
May 29, 2019
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Definitely listened to what you said about the connector. I tried very hard to push the 2 ends together as tightly as I was able too.
I will now cut off the cable ties fixing it to the frame and try again.
 
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crystaljohn

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May 29, 2019
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Cut off cable ties, pulled connector, and reconnected together. It's not possible to push the 2 parts any further together, they are fully home.
 
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vfr400

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The cable is also at the wrong angle, so you must check it for damage under the plastic cap. The slot it comes out of is vertical, but the photo shows it nearly horizontal. Normally, that shouldn't be possible without the edge of the slot digging into the cable.. If you can, shift the whole cable backwards to make the cable go vertically down from the motor
 

crystaljohn

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May 29, 2019
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Ok. I don't have an allen key in my house atm to remove the Metal guard which has to come off before I can pull off the plastic cap. From what I can see at the moment the cable is exiting at about 200 degrees, ( 7 o' clock ). I will do this in the morning.

Thanks for your help, much appreciated.
 
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crystaljohn

Pedelecer
May 29, 2019
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I removed the guard and the plastic nut. I can now see the flats on the axle are parallel with the slots in the frame in which the axle sits. No damage to the cable- it is as the designer intended.cable exiting axle.jpg
 

vfr400

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That's weird. You would only normally find angled drop-outs on a bike with hub gears so you can tension the chain. All bikes with derailleur gears should have vertical drop-outs. Also, it has one of those weird adjusters for the brake caliper mount that you have to shift after adjusting the chain on a hub-geared bike. I've never noticed that before on a Wisper, but I just checked an image of a 905, which is the same.

OK, so motor cable and connector are OK. Now we have to test to see where the fault is. First step is to pull out the controller from under the battery and show us the connectors. You won't be able to proceed any further without a digital multimeter, so if you haven't got one, you have to get one from somewhere.

We've seen a couple of Wispers recently with melted motor wires from the controller, which could happens when you over-load the motor. I think that's where I'm going to place my bet.
 
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crystaljohn

Pedelecer
May 29, 2019
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I have already removed the controller from it's housing. All nice and dry in there, and no sign of any overheating of any connectors. I have disconnected all the High current connector blocks, all look brand new, clean, perfect absolutely no signs of overheating.
I have a digital voltmeter btw, that I am competent with. I'm a retired electrician.
 

vfr400

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Jun 12, 2011
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I have already removed the controller from it's housing. All nice and dry in there, and no sign of any overheating of any connectors. I have disconnected all the High current connector blocks, all look brand new, clean, perfect absolutely no signs of overheating.
I have a digital voltmeter btw, that I am competent with. I'm a retired electrician.
You should do a quick test of the mosfets. Measure the resistance between the black and red battery wires, then between each and each of the three thick motor phase wires. each group of three phase wires should have the same result, though the the two groups of three might be different. Typical readings would be in the range 7k to 14k, but can be a lot higher or lower. The number isn't important, but they should be the same as their partners.
 

crystaljohn

Pedelecer
May 29, 2019
138
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O.K I will try that tomorrow. I believe I have to discharge the capacitor first by shorting the Live and Ground together, is that correct?