Are the KT controllers slightly pessimistic as far as battery level ?

[Peter.Bridge]

Just been on a 15 mile ride on my folding bike with a 36V 10Ah battery and KT controller / display, it is showing half full battery on the KT display, when I measure the voltage with a multimeter it is showing 38.9V

 

[saneagle]

Just been on a 15 mile ride on my folding bike with a 36V 10Ah battery and KT controller / display, it is showing half full battery on the KT display, when I measure the voltage with a multimeter it is showing 38.9V

I've never noticed anything special. It probably depends on your battery too. I know when mine goes down to two bars, I haven't got much left. You know that you can display the actual battery voltage by a short press of the power button to schange the bottom line of the display from total distance to trip distance to battery voltage?

 

[Sturmey]

Just been on a 15 mile ride on my folding bike with a 36V 10Ah battery and KT controller / display, it is showing half full battery on the KT display, when I measure the voltage with a multimeter it is showing 38.9V

You need to adjust your P5 setting. There is a formula that says the voltage when the last bar disappears on your LCD is something like LVC voltage setting + (P5 setting/3.77) but I have never found this really helpful. I think I set P5 =12 for mine (36V battery) but its not something I worry too much about as I spent most of my life driving older cars/vans with dodgy fuel gauges. I tend to hit the center button twice at the end of a journey to read the actual voltage if I am concerned about running out of juice.

 

[saneagle]

You need to adjust your P5 setting. There is a formula that says the voltage when the last bar disappears on your LCD is something like LVC voltage setting + (P5 setting/3.77) but I have never found this really helpful. I think I set P5 =12 for mine (36V battery) but its not something I worry too much about as I spent most of my life driving older cars with dodgy fuel gauges. I tend to hit the center button twice at the end of a journey to read the actual voltage if I am concerned about running out of juice.

Good point. P5 is basically a damping factor for the battery display. If you set it too low, the display goes up and down every time you open the throttle. If you set it too high, it still shows your battery empty after you charged it until you've ridden half way up your street. They give recommended settings for different voltage battery in the manual. The mid point for 36v is about 10, and about 13 for 48v.

 

[Sturmey]

One thing I can recall for certain is that the LVC voltage setting (C12) also has a bearing. In my case its set to the default value of 30v. I can remember setting it higher once to 31V and this scaled up all the other levels on the display. My battery normally starts to show empty at around 33.3v (under load) and this seems to loosely correspond to the formula. ( P5 = 12 and LVC = 30, the battery shows empty at 30v + 12/3.77 = 33.2 volts). I did not pursue this any further.

 

[Jodel]

I'm a relative newcomer to the KT system, so still exploring all the configurable options. I have never paid much attention to the 'fuel bar' display, preferring to look at the voltage displayed instead. Out of interest, I just checked my readings after an 18 mile ride.

48 volt 12Ah battery - initial reading of 53.8 volts on my multimeter.

After my ride:
KT LCD3 display showed 51.7 volts, multimeter showed 51.2 volts (I'm pretty sure the multimeter is correct).
The fuel bar showed 75% charge
My P5 value is set to 15, I'll try saneagles suggested value of 13 to see if that helps accuracy.
I have the P12 LVC set to 7 (40 +1.5)

I really like that the KT display can show voltage and watts used in real-time. It's interesting to see how much voltage drop there is when climbing steep hills and watching the watts required shoot right up.

I've been playing around with quite a few of the KT settings. For example, switching between current control and speed control with P3 value has been a great way way of comparing the two different power delivery methods.

I found in speed control mode that setting the C14 value to '3' - strong assist, gives quite a linear progression across the 5 power levels. The watt meter showed roughly 120 / 220 / 340 / 470 / 740.

I can understand why many of the contributors to this forum recommend the KT controllers, as they can be configured to suit individual preferences.

 

[saneagle]

I'm a relative newcomer to the KT system, so still exploring all the configurable options. I have never paid much attention to the 'fuel bar' display, preferring to look at the voltage displayed instead. Out of interest, I just checked my readings after an 18 mile ride.

48 volt 12Ah battery - initial reading of 53.8 volts on my multimeter.

After my ride:
KT LCD3 display showed 51.7 volts, multimeter showed 51.2 volts (I'm pretty sure the multimeter is correct).
The fuel bar showed 75% charge
My P5 value is set to 15, I'll try saneagles suggested value of 13 to see if that helps accuracy.
I have the P12 LVC set to 7 (40 +1.5)

I really like that the KT display can show voltage and watts used in real-time. It's interesting to see how much voltage drop there is when climbing steep hills and watching the watts required shoot right up.

I've been playing around with quite a few of the KT settings. For example, switching between current control and speed control with P3 value has been a great way way of comparing the two different power delivery methods.

I found in speed control mode that setting the C14 value to '3' - strong assist, gives quite a linear progression across the 5 power levels. The watt meter showed roughly 120 / 220 / 340 / 470 / 740.

I can understand why many of the contributors to this forum recommend the KT controllers, as they can be configured to suit individual preferences.

P5 doesn't really affect the accurancy. Instead, it's the time to change the battery display. If the number is too high, there's a delay in it updating. If it's the number is too low, it dances aboutwith how much power you take.

Do you remember the old car fuel guages that went up when your turned left, down when you turned right, down when you went uphill, and up when you went downhill? Now they have electronic damping in them so that doesn't happen. That's what P5 looks after.