Programming the KT controller - Configuring P5 parameter

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P5 is the customizing parameter for the battery gauge.  It is described as a limiter to reduce excessive fluctuations in the meter during throttle use but it is also used to determine when the display should show the relative depletion of the battery. I personally want 1 bar (value of U in formula below) to tell me that the battery is close to dead because some semblance of actual battery voltage would be nice to know when I'm 15 miles from home. The KT LCDs are supposed to detect battery voltage and determine the base voltage of the pack but at certain voltages, it's possible that it can get confused and think it's seeing a fully charged 36v pack when it's really a nearly depleted 48V or 52V pack. Leaving P5 at 0 just leaves the meter reading at the mercy of the display logic and will probably be OK over time if it can figure out and remember the pack's voltage.

There is a formula that can be used to configure P5 and it incorporates the low voltage configuration in parameter C12


U = (Voltage value from C12) + (P5 / 3.77)


C12 determines the minimum voltage for the battery pack and is customizable (from 2V less to 1.5V more) but is dependent on the smart display's ability to determine the base pack voltage.  It has the following possible values

0= Default value-2V
1= Default value-1.5V
2= Default value-1V
3= Default value-0.5V
4= Default value 30V for 36 V battery, Default value 40V for 48V battery (and 45V for 52V battery ?).
5=Default value+0.5V
6=Default value+1V
7=Default value+1.5V

there is no documentation around the default value for 52V batteries but it should be ~42V.  Since there is nothing that specifies 52V support we'll need to assume that the smart display will default to 40V for the default voltage so C12 needs to be set for 7 (minimum pack voltage of 40+1.5 = 41.5V or 45V if the display can successfully detect 52V).

7 Seems like a nice conservative value to set as minimum voltage to avoid stressing the battery pack with excessively low voltage drawdown.

<pure speculation>
I suspect removing the battery or powering down the battery will cause the smart display to have trouble determining the base battery pack voltage.  

For example, if I plug in a 58V battery pack, it can figure out that it's a 52v pack, but if I run the pack down to 54V and then unplug it and replug it (without charging first) will result in the display thinking it's looking at a fully charged 48V pack.
<\pure speculation>


For consistent results, it's probably best to only plug a fully charged pack to avoid any confusion for the smart display. 

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