E-Scooter project build. 50 kw peak (video online page 4)

John in CR said:
FWIW, there's no such thing as a "higher torque" version of an otherwise identical motor. "Slower and lower power" is a better description given that our voltage is limited. If you're doing lot's of stop and start riding, and/or hill climbing it will likely enjoy an overall efficiency advantage, but that's it. They're capable of the same torque. The higher Kv motor just needs more current to generate that torque, but it is wound with thicker wire so it can handle the higher current. If you're not having heat issues, then there's no reason to go for the slower motor. :mrgreen:
Click to expand...
He wants to overcome the kellys low current limit under certain speed, I do not know how kellys are detecting it but if it is inductance or resistance wise, he should try it. small wheel is winner in every case. :)
 
I think I agree with John, I couldn't help but think if your getting 60A x 72v = 4320watts/sec from the kelly controller that should get your butt moving pretty good I would of thought, but I still have my mind living in the ebicycle world mind you.
 
scooter is about 130kg at least. plus my weight and maybe a passenger.
trust me when i say that 60A is nothing. sometimes i cant go up a thin border from a sidewalk or start on a small hill. the kellys are rediculously bad at take off performance. sometimes it just shut off and say: over voltage error! when i try start at a small hill. do you know how it feels to have a scooter which is able go 140 and scare the shit out of you but get stucked in traffic at the slightest hill, cars pile up behind you and go crazy because you blocking traffic? well kelly teached me what it feels... and i was pretty pissed. it happend once and that was one time too much
 
The answer has to be to find a better setting for the controller. Hillsofvalp used his for nearly a year before a small controller setting change on his Kelly's gave him rocket performance off the line. If it's low inductance causing the Kelly to self limit to protect itself try adding a coil on each phase wire.

I'd talk to Kelly more. I think the issue is that it's getting too much phase current multiplication at very low rpms. With the Infineon type controllers the way to cure it is by using a lower ratio of phase current limit to battery current limit. That allows you to increase both current limits. eg With my lowest inductance motor I use a 1.3:1 ratio of phase current limit to battery current limit. With that 36fet controller I settled on 425A/550A current limits, and while battery current didn't reach the full 425A until about 25mph, the 300-350A or so I would draw from the battery on launch meant you better be prepared when you twist the throttle. :shock:

With it limiting to 60A from the battery off the line, I'd bet a setting change that's non-intuitive will help. eg If you have it set to higher torque, then try "balanced". If the throttle is set to fastest start, the slow that down.

It's most definitely not the motor, so getting a new one should be at the bottom of the list. OTOH, go ahead and purchase that new torque model motor, and sell me your used speed wound motor. I'll demonstrate how to get it to launch hard. :mrgreen:

John
 
thanks for all that. even i struggle to understand half of it. :mrgreen:
i had played around the settings alot. there are no better results as 50-60 amps at take off.
i am also in close contact with kelly and they said not only once this controller is like this. cant change and i should live with it. they also refused to change it to a bigger version and let me pay the difference. instead of this they want me buy a new controller. WTF?! :evil:

back to your buddy. he should tell us the rocket performance setting of his kelly controller right now! please be so kind and contact him. that would be a great help. i still dont give up because i hear from many sites about the setting of kellys and how it changes the take off performance.
but as much i try: i can not find any setting which let me start better.

EDIT: my offer still stands! i pay cash if somebody help me to find the setting to make the lame kelly feel like a real controller. (btw: today i try several times. start up current isnt 60A, sorry my fault. the real start up current is 20A :roll:
tested it about 5 times from stand still and throttle to 100% as fast as i can. amps go up to 20A and stay there about 1 sec. then ramp up to 60A for 1,5sec. and i get 180A AFTER hit 65km/h.
 
hi @steam25
so you wouldn't recomend it for fast acceleration?
becouse that is what i want. what "cheap" controller do you advice for fast acceleration?
thanks.
 
I don't know, I think it was sold on this forum, I got mine from a local guy, but mine is stock, non modded. It's 48v and 80a, but you can mod it to 120v and 250a. Something like this:

http://endless-sphere.com/forums/viewtopic.php?f=31&t=51891

I'm selling mine because I got Kelly, I could use it but I would have to use throttle tamer or similar device for slower response.
 
So how goes the hunt for a new controller steam ? Hope fully well.
Jim
 
jeah ok post it. but please use some of my better photos. that looks very terrible...
send me PN please.


CONTROLLER:
we decided to build our own controller later. for now stick with kelly. my first controller was broken already when buy it. that caused the poor performance. after it went up in a plasma fireball and kelly replaced it, the scooter goes MUCH better. still not what i want. but better.
 
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