SW900 speed measurements without PAS

GuitarHero1969 · Sep 7, 2021

I’m using my bike (Voilamart 1000 watt kit and 52 volt battery) without PAS sensor since I couldn’t get the pedal crank arms off.

The speed is shown as 62mph which is nonsense.

Is there anyway the SW900 can measure the speed of the bike accurately without the PAS sensor ?

E-HP · Sep 7, 2021

GuitarHero1969 said:
I’m using my bike (Voilamart 1000 watt kit and 52 volt battery) without PAS sensor since I couldn’t get the pedal crank arms off.

The speed is shown as 62mph which is nonsense.

Is there anyway the SW900 can measure the speed of the bike accurately without the PAS sensor ?

The PAS sensor has nothing to do with the speed read out. You need to set your wheel size (P06), and units (P02) in order to calibrate your speed.

GuitarHero1969 · Sep 7, 2021

Yes, both of those are set accurately!

E-HP · Sep 8, 2021

GuitarHero1969 said:
Yes, both of those are set accurately!

You have to set P07, depending on whether you're using an external speed sensor, or a signal from the motor hall sensors. If the latter, you need the number of magnet poles.

GuitarHero1969 · Sep 8, 2021

I’m not using a speed sensor, so would I set “number of magnets” to zero ?

E-HP · Sep 8, 2021

GuitarHero1969 said:
I’m not using a speed sensor, so would I set “number of magnets” to zero ?

Depends on your motor. I believe that a 9C clone motor has 46 poles, or 23 pole pairs. I don't have a Voilamart motor, but the ones I see on ebay look to be 9C clones.

GuitarHero1969 · Sep 9, 2021

Setting P07 to 46 did the trick!
Many thanks

SW900 speed measurements without PAS

GuitarHero1969

100 µW

E-HP

10 GW

GuitarHero1969

100 µW

E-HP

10 GW

GuitarHero1969

100 µW

E-HP

10 GW

GuitarHero1969

100 µW

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