KT LCD p1 won't save

[jimriley]

I have an old crystalyte DD hub, resurrected with KT 25a controller and lcd3, working fine, but just can't get the P1 magnet count to stick below 20. Afaik there are 18 magnets. The speed is 1 or 2 mph below actual, as checked with a speed app on phone.
I've tried a variety of options, setting P1 then saving with long press of I/O , setting and scrolling through to P5 etc. It keeps reverting to 20!
Any thoughts welcome.
I could cut and run, get a speed sensor on wheel, but can't see why this shouldn't work. I have read that others have had the same issue.

 

[Nealh]

If it is a DD hub then usually P1 is 46, one doesn't use motor magnet count as the setting.

 

[jimriley]

Thanks I'll give it a go tomorrow.

 

[jimriley]

Setting p1 to 46 made it worse. From what I've read with a DD motor p1 equals the number of magnets, which makes sense if p1-20 is almost right. The destruction manual says p1 can be 1 -255 IMMSMR, so why won't anything below 20 save.

So I tried a different tack, wheelspeed sensor with signal wire connected to speed wire on controller with p2 - 1, it sort of worked but the reading jumped about a lot.
So still no nearer a correct speed and distance reading.
Any thoughts welcome.

 

[jimriley]

I sent an email to torquetech, I got the kit from them. Interesting reply, a possible solution. The P1 range in the destruction manual is an error, it should read 20-255. So it won't save owt below 20.

Hi Jim

I have a previous customer that once experienced the very same problem with a Crystalyte 408 motor.

Firstly, I should confirm an error with KT LCD documentation, where the user guide incorrectly states that custom parameter P1 can be set to 1-255. As you have discovered, '20' is the minimum acceptable value.

The solution to the problem was to set the wheel size to the next size up in order to bring the displayed speed back into alignment with the true GPS measured speed.

An erratic external wheel speed sensor reading will usually be caused by either a sensor positioned too far from the passing spoke magnet, or electrical noise on the signal line caused when running unshielded cable in parallel with high power motor or battery wires.

Best regards,

Dan

 

[jimriley]

Update, I moved the wheel speed sensor wire away from the rest of the wires, lo and behold, it works. So all now functioning as it should.