KS App/Firmware Improvements Suggestions! NEED YOUR VOTE!

[Chriull]

6 hours ago, WheelHead said:

 

From engineer Careys comment that KS is reducing speed because at faster speed “the wheel would not withstand aggressive acceleration”. With that logic, the new 2000w ks18 would need a further speed reduction because at 2000w, hard acceleration would take even more current from the battery. The new ks18-2000w wheel would need the speed reduced to 30km/hr at 70%, not 56% like the 1200w due to the high current demand in hard acceleration of that wheel. So with this logic that KS is using, the max speed can only be used at the top 30% of the battery....

The acceleration of the wheel is directly proportional to the current flowing. So the main limits for acceleration (possible current flow) are:

- battery ability to provide this current (how much cells are in parallel, which cells are used, ... ?to some extend also the remaining capacity of the battery?)

- difference between back EMV (voltage generated by the motor, which is directly proportional to the speed) and the battery voltage (which gets less the lower the remaining capacity is). The maximum possible current (acceleration) is determined by this voltage difference.

- some limitations implemented in firmware

The KS14, KS16 and KS18 have (quite presumably) different motors with a different kV (Volts generated per speed). So they have different safety margins (battery voltage - generated voltage) at the same speeds and by this could need different speed reductions over battery capacity.

A differentiation by battery pack size (i.e. KS16 340Wh vs 840Wh or KS18 680Wh vs 1508Wh) would make sense (to some extent) - but the firmware has no clue which battery pack is inside the wheel.

 

The announced motor wattage is some quite "esoteric" number which is only some "hint" for a (hopefully) maximum continous rating. Maximum peak power should be something much higher (limited by the melting temp/max temp of the copper wires in the motor coils, magnetic saturation of the metallic core, max temp of the permanent magnets, max force possible with the generated magnetic flux, etc...)

To get some rough idea of the max possible power output of wheels you can take a look at the outcome of some dynamometer tests with different wheels:

So the result for the KS18-1360Wh was 2,6kw, KS-18 680Wh 2,3kW, KS16-840 2,2kW and for the KS16-340 1,9kW...

Also electro-sport.de has an own dynamometer by now and released some youtube videos - but i did not have time to really look at them...

[WheelHead]

Thanks for the info chriull.  As you said we don’t know what the EMV is for a particular 2000w motor, but it would probably take more current than a 1200w motor at 30km/hr at hard acceleration wouldn’t it?  Is my assumption correct that  a higher wattage motor like a 2000w will be slower than a 1200w after 30% battery capacity?  Because a 2000w will have to be speed limited more because of the higher current draw with hard acceleration.  That seems to be the logic in the firmware.  Just like the V8: abinder3 said: the V8 can go faster than the ks18 when both are at 50%.  Maybe at some point KS will account for the battery capacity of the wheel also. 

I’m just trying to figure out if a 2000w motor is worth it over a 1200w motor for speed after 30% with current firmware implementation.