Insight and Sweet-Spot for Motor Power Constant / Battery Current Settings?

DK7
Posts: 9
Joined: Sat Dec 07, 2019 7:57 am

Insight and Sweet-Spot for Motor Power Constant / Battery Current Settings?

Postby DK7 Mon Dec 23, 2019 4:47 am

So I'm keen to get some extra power from the KS Max, but without overloading the motor and / or wiring of the scooter with too many amps.

Questions:
-Is it correct to assume that we should only change EITHER the Motor Power Constant (MPC), OR the Phase and Battery Current values, but not MPC and Currents together?
-From my experience with the M365, it seems the best way to get increased hill-climbing power WITHOUT making the acceleration too jerky, is to increase the Battery Current value while leaving the Phase Current and MPC values at stock settings. Is this right for the KS Max as well?

Hypothesis:
-Assuming I am making no changes to the MPC (leave it at 51575), leave the Phase Current at 55,000mA, and increase the Battery Current to 31,250mA (25% increase), this should give a decent but sensible bump in uphill power. Final question: can anyone with knowledge of the electrical system and wiring in the KS Max give an indication if this should be pretty safe, or is it likely to overload something?

Thanks in advance, happy scooting!
Viking
Posts: 1
Joined: Tue Dec 24, 2019 11:29 am

Re: Insight and Sweet-Spot for Motor Power Constant / Battery Current Settings?

Postby Viking Tue Dec 24, 2019 12:29 pm

I cannot directly answer your question but I can give some insights after flashing my new Ninebot MAX G30D with the 1.2.6 CFW. I do this, of course, with all disclaimers 😏

My (only) patches:
- Motor Start Speed: 3km/h
- MPC: 40145 (you can either patch MPC OR Phase/Battery Current)
- Power-based throttle (highly recommended for this power setting)

I had calculated I needed the MPC i.o. to reach ~900 W max. power (compared to the default ~700 W burst power the MAX is advertised to have). And as you can see below I got pretty close to this.

I tested it today under the following conditions:
- Outside temperature 7 Celsius
- Battery/Board temperature at start 23/23 Celsius
- fully charged (41,35 V/15300mAh)
- driver weight 90 kgs
- flat course, little wind

My results are as follows (values for current according to Ninebot App
- max speed freewheeling: 32km/h (default were 20 km/h)
- max driving speed APP/GPS: 31/30 km/h (20km/h)
- acceleration 0-20 km/h: 2,9s (5,5s)
- acceleration 0-25 km/h: 4,8s (—)
- power/current/voltage under full load acceleration @10km/h: 875W/22,22A/39,37V
- power/current/voltage, full load acceleration @20 km/h: 862W/21,95A/39,35V
- power/current/voltage, full load acceleration @25km/h: 680W/17,23A/39,57V
- power @30km/h ~320W
- total distance 8,8 km (with a lot of full accelerations and top speed)
- Battery/Board temperature at finish 25/24 Celsius
- remaining battery 80%/12240mAh

Due to the low outside temperature I would not dare any prognosis on how the parameters would change in summer. Neither can I make any presumptions on how the electronics would behave under sustained currents around the above reported max. values of ~22-25A, that would assumingly be reached e.g. in long climbs. Still, there‘s no hint so far that my KS MAX struggles with this setup, and the riding experience is very smooth and powerful.

Hope this helps.
DK7
Posts: 9
Joined: Sat Dec 07, 2019 7:57 am

Re: Insight and Sweet-Spot for Motor Power Constant / Battery Current Settings?

Postby DK7 Thu Dec 26, 2019 8:55 am

Sounds good, cheers for the info! I will do some testing on my own custom firmware setups.

I have a feeling that the BMS limits the maximum amperage of the battery pack at a level that we can’t control through firmware alone. It seems to be around the 25 amp level you mentioned.

I know my m365 maxes out at around 20 amps during sustained hillclimbs, no matter how high I set the MPC or battery current / phase current - and yes i’ve tried each setting individually!
thedookster
Posts: 1
Joined: Fri Jan 03, 2020 9:09 pm

Re: Insight and Sweet-Spot for Motor Power Constant / Battery Current Settings?

Postby thedookster Fri Jan 03, 2020 9:13 pm

please keep me updated on this!
I have a G30P.
I have used my MPC of 48000, no other settings changed
and i have a custom serial number 'N4GSD1111C1234'
and I can get max speed 20 MPH (32.19 KPH) freewheeling

I am wondering if I can weak my MPC even lower but the page at https://max.scooterhacking.org/ makes it seem like 48000 is already 'maxed out'

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