Apparent lack of power to hub motor

[StuG]

Hi,

Today I installed a front hub conversion kit to my hybrid bike.

It has a 36v 13ah battery and is fully charged.

When I tested it first time earlier, the power was very light to the motor. When the throttle was pressed, power went to the wheel, but not enough to pull me along. Also didn't appear to be any difference using the PAS when peddling.

I thought the brake disc may be catching in the caliper. But the lack of power is the same when I've taken the calipers off.

Wires are all colour coded, so are linked up correctly. LCD says the battery is fully charged.

Any advice would be greatly appreciated.

Thanks.

 

[Nealh]

What kit did you buy just out of interest ?

 

[StuG]

Front hub kit from Woosh

 

[Woosh]

How to check the kit:

check the motor connector.
There is a ring imprinted on the motor's side of the 9-pin connector.
You want to line up the parts of the connector so that two arrow heads face one another then push the two parts together until the ring reaches the controller's side.
Post a picture of the motor connector if you are not sure.
Switch on the LCD.
Lift the motorwheel off the ground.
Press and hold the - button on the LCD to enter walk mode.
Make sure you see about 4mph on the speedometer.
Turn the cranks and check that the LED on the pedal sensor flashes and the motor starts.
Check that you can reach 15mph easily by turning the cranks.
If you have fitted the throttle:
Check that the throttle works and you can reach easily 15mph.
If you have fitted the brake sensors:
Squeeze one brake lever at a time. Switch on the LCD. You should see '25' on the LCD. Release the brake lever. The '25' should clear.
Take it out for a test ride.

 

[Woosh]

A possible cause is the side of your throttle touches something on the handebars. Unplug the throttle to see if the problem goes away.
If it does, then move the throttle a bit, leaving about 1mm gap between the throttle and other things.

 

[StuG]

Hi Woosh,

Thanks for instructions.

So, walk mode causes the wheel to rotate freely and easily. The led flashes when turning the crank.

No speed read out on the LCD though and '25' doesn't appear when trying the breaks.

Pressing the throttle sends power to the wheel but it struggles to rotate. There is space around the throttle.

Thanks

 

[Woosh]

the lack of speed readout is a concern.
The speed sensor is inside the motor.
Unplug the throttle and brake sensors to narrow the possibilities.
If the problem does not go away, unplug the motor connector, check the 9 pins for any sign of damage and reconnect.
If the problem does not go away, can you post a close up picture of the motor connector (and a bit of motor cable) as it is at the moment?

 

[StuG]

Unplugged the brake sensors and throttle. Still no read out when pressing for walk when the wheel rotated. When I pressed for a second time, the LCD says "Push" but the wheel is no longer rotating

 

[Nealh]

Does the motor wheel spin freely with no power ?
Double check you have mounted the motor wheel correctly and that it isn't being hindered

 

[Nealh]

In the first pic the motor connector is pushed firmly in place up to the raised line but on the bike the second pic (with it cable tied to the fork) it isn't the female end needs to firmly be pushed to the raised line as the hall sensors won't be registering, hence no odo reading and lack of power.

 

[StuG]

I think it is. Doesn't spin as freely as a standard wheel, but figure the motor adds some resistance. However if I tighten the nuts up that starts to restrict the movement

 

[StuG]

In the first pic the motor connector is pushed firmly in place up to the raised line but on the bike the second pic (with it cable tied to the fork) it isn't the female end needs to firmly be pushed to the raised line as the hall sensors won't be registering, hence no odo reading and lack of power.

Still no difference

 

[Nealh]

The raised line should all but touch the female connector end.

Also show us a pic of the motor wheel in the fork drop outs preferably with the bike upturned.

 

[Woosh]

in the last picture, the plug needs to be pushed in another 1.5mm

 

[Woosh]

I think it is. Doesn't spin as freely as a standard wheel, but figure the motor adds some resistance. However if I tighten the nuts up that starts to restrict the movement

the motor should freewheel in the forward direction, engages the gearbox and resists a bit in when you reverse.
If it does not freewheel in the forward direction, please post some close up pictures of the washers and wheelnuts.

 

[StuG]

Right. First off, apologies, first time doing something like this, appreciate both your help. I didn't put the connector back properly after checking the pins. Power now sorted.

With the wheel, see pics. Loosened the nuts, throttle now works with the readout to 15mph. If I tighten up too much, the wheel starts sticking.

Thanks

 

[Woosh]

check first that the brake pads don't touch the rotor.
Use a torch to look into the space between the brake pads,
If one of the pads touches the rotor, you need to loosen the two M5 bolts holding the caliper and adjust the caliper so that the rotor runs true in the middle between the two pads.

 

[Nealh]

Is there a flat washer fitted to the axle before the AR tabbed washer ?

On the disc side there is an inboard axle retaining nut that also acts to secure the bearing clear rubber seal and the seal washer in place, this might be pinched up to tight ( it may need just a 1/4 or 1/2 turn AC/W ) and when you tight the outer hub axle nut up might be pinching it all up too tight against the bearing casing the rotation stiffness.

 

[Woosh]

from memory, only two washers on each side. The tabbed anti-rotation on the inside of the jaw, a thinner washer on the outside of the jaw.
They look OK on the pictures.
That's why I thought he may have brake binding.
We'll know tomorrow when the OP checks his brake pads.
Another possibility is he may have used 12mm rotor bolts instead of the 10mm rotor bolts that are supplied with the XF07.
I'll ask him to check the rotor bolts next.

 

[Nealh]

Yes can see the possible problem if Stu used the 12mm rotor bolts but using them wouldn't affect how the motor wheel spins by tightening up the axle nuts too tight, The rotor bolt issue would show up beforehand .