Very weak PAS

[alban]

PAS engages but only supplies weak assist - only a couple of As drawn. No-name controller 36V 350W Brushless E-bike& Scooter Controller With Hall | eBay
Throttle fine. Tried reversing rotor, cleaning it and sensor. Can't get it nearer to sensor - about 4mm. Tried re-self studying.
Blurb says 'provide 1:1 power' whatever that means. Perhaps it requires a torque sensor?
3-speed switch wired by me to give high speed according to blurb.
Any ideas guys?

 

[Deleted member 4366]

A couple of ideas:

Just to eliminate it as a possibility: Make a bridge wire and poke one end in the middle position of the three speed switch connector and the other end in one of the other positions. One way will make it faster, and the other slower.

Some controllers have an algorithm that gives motor speed (power) according to cadence. Ideally, you need to get the bike up on a stand and measure the wheel-speed whilst turning the pedals. You'll then be able to see/hear/measure what effect pedal-speed has on motor speed. If you have to pedal at 120 to get motor speed of 15 mph, then you need a magnet ring with more magnets. You can buy magnets on Ebay, drill holes and glue them in. You have to put them in the right orientation, so check the pattern that you already have.

You also need to get the sensor closer to the magnet ring in case it's missing pulses. Make a spacer out of 3mm thick plastic; unscrew the sensor from the bracket and use a longer screw to re-attach it. Epoxy it all together if you can't get the screw to work. You need a gap of 1mm

 

[alban]

Thanks Dave. Tried changing the 3-SPD switch connections with little effect at slow speeds which is when I want full power. Pas works as I wish with a spare controller so I think that it's the algorithm rather than disc etc.