KT-LCD3 display - speed report wrong

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Firedog   10 W

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KT-LCD3 display - speed report wrong

Post by Firedog » May 17 2019 6:47pm

I just installed a KT36/48VPRL controller with a compatable KT-LCD3 display driving a Crystalyte 408 front hub with 54V. The speedometer function is calibrated with a setting for wheel diameter (26,700c,28,29) and P1 (Motor characteristic parameter setting) where P1= motor gear reduction ratio x number of magnets. The 408 has 18 magnets and is a direct hub. The manual says P1 can be 1 to 255. I should use P1=18, but it will not keep any setting below 20. At 20 the report is about 10% low (even using 29 diameter). Any one have a fix or an idea get a more accurate speed and distance report?

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E-HP   1 MW

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Re: KT-LCD3 display - speed report wrong

Post by E-HP » May 17 2019 7:22pm

Firedog wrote:
May 17 2019 6:47pm
I just installed a KT36/48VPRL controller with a compatable KT-LCD3 display driving a Crystalyte 408 front hub with 54V. The speedometer function is calibrated with a setting for wheel diameter (26,700c,28,29) and P1 (Motor characteristic parameter setting) where P1= motor gear reduction ratio x number of magnets. The 408 has 18 magnets and is a direct hub. The manual says P1 can be 1 to 255. I should use P1=18, but it will not keep any setting below 20. At 20 the report is about 10% low (even using 29 diameter). Any one have a fix or an idea get a more accurate speed and distance report?
One solution is to get an external sensor, and the controller will ignore those other settings beside wheel size, although I've seen a couple a threads describing a systematic version of trial and error with P1 combined with other settings.

I could get the speed close, but couldn't match my GPS until I added the external sensor.

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amberwolf   100 GW

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Re: KT-LCD3 display - speed report wrong

Post by amberwolf » May 18 2019 1:01am

You could use 180, then just keep in mind the decimal will just be off by one. ;)


Alternately, you could look up the open-source firmware for the KT and LCD3 by Casainho / stancecoke / etc; there's a few threads and it's a lot of reading, but I understand it's much more configurable than the default firmwrae.

Firedog   10 W

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Re: KT-LCD3 display - speed report wrong

Post by Firedog » May 20 2019 11:52am

couldn't match my GPS until I added the external sensor
Thank you!

Instead of ordering and waiting for a external speed sensor, I pulled a PAS sensor and an old spoke magnet out of my parts bid. It works perfectly.

I set up this tandem to use a Crystalyte 5303 or a much lighter 408. A 5 minute swap. The speed sensor rpm input means I don't have to reprogram the display after a change. Nice
Attachments
Speed sensor r.jpg

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