Urban Movers Uglider UM36X 'project'

[mikeybhoy]

Hi Forum,

while working on a job at the local council offices, the staff came around asking if anyone was interested in buying old e-bikes. They had about 12 in total in various conditions (flat tyres, cut cables etc.) but I bagged a UM36X for the princely sum of £25 that was a bit manky, had a flat, but otherwise looked in working order.

Although listed in the manual as optional, it comes with a crank mounted torque sensor.

The bike did work, after a fashion, in that with a bit of a peddle the motor would kick in for a couple of seconds, giving a wee bit of oomph but then didn't seem to provide much power after that - a bit of a let down really.

Read up on the technology and it seems this is what a torque sensor does, only provides enough power to get you moving and a little bit of assist, until if determines you're really having to pedal hard and then it gives a bit more juice.

Anyhoos, after a bit of a powerwash, it stopped powering the rear wheel. Wheel and battery were OK as attaching battery direct to wheel would spin the wheel briefly but battery would then cut out. I suspected the crank mounted torque as there seemed quite a bit of play in the wire going in. At one point, with a bit of wiggling the rear wheel did spin up, but have had nothing after that.

Made a bit of a mess trying to get the crank off with a big hammer and given the cost of replacements (and the price I paid for the bike) I am looking to replace the cranks with new standard ones, but add a handlebar throttle instead (to replace the torque sensor).

Is this possible? Can the torque sensor input on the VPAC be bypassed like this, or am I stuffed?

Cheers all

Mike

 

[Deleted member 4366]

First thing: Did you charge the battery? Did you measure the voltage on the battery?
Next thing: I thought these were three-phase motors. How many wires are there connected to the controller?

 

[billadie]

Urban Mover Torque sensor's do not like water. I nearly killed mine by washing the cranks see;

http://www.pedelecs.co.uk/forum/electric-bicycles/13830-urban-mover-not-moving.html

If your controller is OK you can connect a throttle. Urban Mover in Cheltenham can supply.

 

[mikeybhoy]

First thing: Did you charge the battery? Did you measure the voltage on the battery?
Next thing: I thought these were three-phase motors. How many wires are there connected to the controller?

Hi d8veh, yes battery has been charged over night and shows full power on the connected power-ometer.

There are loads of wires connected to the controller, but if you mean from the motor wheel, there are 3 thick wires and 5 (from memory) smaller wires.

 

[mikeybhoy]

Urban Mover Torque sensor's do not like water. I nearly killed mine by washing the cranks see;

http://www.pedelecs.co.uk/forum/electric-bicycles/13830-urban-mover-not-moving.html

If your controller is OK you can connect a throttle. Urban Mover in Cheltenham can supply.

Hi billadie,

that threads an interesting read and glad you got it sorted in the end. So assuming the controller is still OK, I can simply disconnect the torque sensor entirely and run it from the throttle? I read in your thread that the controller has to sense 0v before providing power to the rear wheel (a safety measure) so I guess disconnecting it will always mean 0v.

Is it a specific type of throttle needed for this bike, or would any tom, dick or harry throttle work.

Cheers

 

[Deleted member 4366]

It's a three phase sensored motor, so connecting the batteru to the motor won't do anything other than burn it out. Only the controller can power the motor. the controller is the thing with all the wires coming out of it. It's a shame you smashed up the crank because the torque sensor has no detrimental effect. You've totally misjudged how it works. You could have connected a normal throttle with or without the torque sensor in place. The torque sensor tells the controller when you're pedalling. The controller gives continuous power to the motor. If your power kept cutting, it's for a different reason - nothing to do with the torque sensor.

You have to measure the voltage of the battery about half hour after charging to see if it's any good. lights/LEDs mean very little.

You should never power-wash an electric bike. The electrics, including the motor, are not sufficiently waterproof. As Bill points out, water in the torque sensor can not only wipe out the torque sensor, but also the controller.

So far, you've done a lot of bad things to this poor bike. Sorry to be blunt, but you need to slow down a little bit and ask first before attacking it again.

My assessment from what you've said so far is that all that was wrong with it is a weak battery, which probably can be easily fixed. When a bike doesn't work properly there's simple tests that can normally quickly get to the root of the problem. You need to start with the battery.

 

[mikeybhoy]

Just had another idea if that doesn't work. Assuming that the spare 4-way connector is for a throttle with LEDs, we need to confirm that the yellow has battery voltage on it, so could you measure the voltage between the yellow and the black - being careful not to touch the other pins with your probes. It might be easier to stick them up the back of the connector. If you get about 26v there, then the green is the throttle signal and red 5v. You should confirm 5v between red and black. If you don't get those voltages, report back what you do get.

if you then join the green and red wires, the motor should give full power like you've opened the throttle fully. Make sure that the wheel's off the ground unless you want to chase after your bike. The easiest way to do it is to scrape a bit of insulation off the wires to touch them together unless you know how to release the pins from the connector by pushing back the barb with a needle.

Thanks again d8veh, you're right of course, I think I've been a bit quick, not to say cack-handed, with the 'project'. I followed your advise above from another thread. Measuring the voltages above I get 25.9v between yellow and black, 4.9 between red and black. Battery was last charged about a week ago. I then shorted the green and red with a metal rod. I could feel the wheel very slightly pull forward (almost imperceptible) but not enough to actually turn the thing. I was shouting through to the missus about what a waste of £25 when the next thing I knew the wheel started spinning up quite fast (I have the wheel removed and in a vice). I nearly kekked myself with the shock

Tried again (I'm shorting using a bit of metal across two needles stuffed down the back of the connector) and nothing as before, however I didn't realise that the connection has to be made for a few seconds before the power actually kicks in. Wheel up to full speed again. It does seem a wee bit inconsistent with the timings before the power kicks in (between 2 and 5s), but once power is applied it remains pretty consistent.

I'll get a throttle ordered up tonight and take a trip to Halfrauds for some new cranks.

Cheers

 

[Deleted member 4366]

If you could take a picture of all the connectors from the controller spread out, I can tell you if there's a connector for the throttle, or whether you have to do something else. The battery voltage is getting a bit low. If it goes much lower, it'll start cutting out. You need a 29.4v charger (or thereabouts but not higher). They're often sold as 24v chargers. It has to be one for lithium batteries. A 24v lithium battery is about 21v when flat and 29.4v fully charged.