Max speed setting on KT controller/LCD5 display setup

Cisco-man

Esteemed Pedelecer
Sep 27, 2023
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72
Hi. This has me puzzled. I’ve got a KT 17A controller, LCD5 display, 8 magnet PAS, Swytch 250w hub. If I set max speed to 25 kph (legal limit) I get assistance up to 7(ish) mph. To get it to assist up to 15 mph I have to set max speed to 50kph. So something seems to be halving my max speed setting! The bike runs smoothly, and the actual speed displays correctly.

can someone give me a clue what it could be?

Here are my settings:-


P1 96
P2 1
P3 0
P4 0
P5 12
C1 2
C2 0
C3 8
C4 0
C5 10
C6 3
C7 0
C8 0
C9 0
C10 n
C11 0
C12 4
C13 0
C14 2
C15 6
 

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Nealh

Esteemed Pedelecer
Aug 7, 2014
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West Sx RH
One would say the P1 setting is wrong, try 180 - 192 to see what happens with the speed setting at 25kmh.
 

Cisco-man

Esteemed Pedelecer
Sep 27, 2023
297
72
Result! Thank you Nealh. I set P1 to 192 and all seems to be well.

All the posts I’ve seen on using a Swytch hub talk about P1 being 96 so not sure why my wheel should be different. Here’s what has been posted before:- Swytch hub is (6:1 Ratio) 6 x 16 Magnets in the internal Hub, so P1 = 96.

Anyway, it works - so thanks!
 
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Nealh

Esteemed Pedelecer
Aug 7, 2014
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One can only assume your hub is 12:1 ration or 12:6:1 or something similar.
I believe they are AKM hubs so a different winding speed can mean internal ratio is different.

This was an issue with many a AKM 100 or 128 hub one really never new 100% what the claimed ratio was so one had to work the P1 value up or down to get an idea by checking the 25kmh speed setting with a gps reading to get it accurate . Then from the P1 reading one could work out the motor ratio.
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
20,917
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West Sx RH
Result! Thank you Nealh. I set P1 to 192 and all seems to be well.

All the posts I’ve seen on using a Swytch hub talk about P1 being 96 so not sure why my wheel should be different. Here’s what has been posted before:- Swytch hub is (6:1 Ratio) 6 x 16 Magnets in the internal Hub, so P1 = 96.

Anyway, it works - so thanks!

We usually have an answer for most issues.
 

saneagle

Esteemed Pedelecer
Oct 10, 2010
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3,168
Telford
KT controllers use two speed signals for two purposes. The Speed sensor and its settings are used to calculate the speed displayed on the LCD. The controller uses the motor hall sensors to get the speed for the speeed cut-off.
 

Cisco-man

Esteemed Pedelecer
Sep 27, 2023
297
72
KT controllers use two speed signals for two purposes. The Speed sensor and its settings are used to calculate the speed displayed on the LCD. The controller uses the motor hall sensors to get the speed for the speeed cut-off.
Thanks both. I’m learning!