24S goes only 59km/h

rg12

100 kW
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Jul 26, 2014
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Got my chinese 36A AliExpress controller, connected it to my brand new Inokim OX and 24S 20Ah 8C battery, all 100% new and it goes 59km/h (measured with a GPS app).
It has a 3 speed switch which has two identical speeds (no different torque between them) and one slower speeds.

Packs is charged to 100V and meh, does nowhere.

Now, the Inokim OX is a scooter we here in Israel mod all the time, it goes about 55km/h with a stock 60v chinese battery and stock twenty something amp controller.

Could it be that my controller's RPM is limited for some reason?
Usually chinese controllers are so stupid they don't limit anything.

Any idea before I replace it?
 
check the Kv of the motor.

Kv = voltage = RPM.

10Kv means you get 10RPM at 1V.

but if you have the same model motor then you are probably hitting the power limit of the controller or the eRPM of the controller.

next time buy something like a KLS-M from kelly.
 
What speed does the wheel go when not on the ground? If it's the same as when on the ground, then the system is speed limited, usually by the controller.

If it is a little faster but not much, then it's probably the motor kV not fast enough for that battery voltage (probably not, based on your report of the unmodded speed).

If it's a lot faster, then it's probably just insufficient power from the controller and/or battery to go any faster against the load (weight, slope, wind resistance, etc).
 
It can't be lack of current since I get the same speed with an identical scooter and motor with only 60V and 25A.

I don't have a speedometer for the wheel (measuring with gps) but I know what 80-90km/h wheel speed sounds like in the air and that is not it, it should spin much faster in the air.

I'm used to chinese controllers to be pretty simple, for instance a 45A 60V system on an mtb 26" goes to 60-65kmh. 45A 72V goes to about 70-75kmh...

btw, can I shove 24S into a 90V kelly controller?
That's why I went with a simple chinese controller, the 72V have caps rated at 100V and also fets are for minimum of 100V so it just works and doesn't blow.
Do you think kelly will hold? and do they have a limit for the 90V in the software?
 
voltage dicates speed. not current.

and the 72v kelly is locked at 90v max. partly because of capacitor rating and the mosfet rating. they cant handle much more. kelly sells plenty of high voltage models that can run 24S packs or more.
 
flippy said:
voltage dicates speed. not current.

and the 72v kelly is locked at 90v max. partly because of capacitor rating and the mosfet rating. they cant handle much more. kelly sells plenty of high voltage models that can run 24S packs or more.

I know that but current can affect speed in case the riding speed is slower than the max wheel speed spinning in the air so more current needed to achieve full rpm but that is not my case though.

About kelly, yeah but they are pretty big...it's for a scooter with small space.
 
rg12 said:
I know that but current can affect speed in case the riding speed is slower than the max wheel speed spinning in the air so more current needed to achieve full rpm but that is not my case though.
About kelly, yeah but they are pretty big...it's for a scooter with small space.

if the wheel is just spinning in air you need just 1A or less to get it going at its full speed. you need volts. amps is only needed for power once you are putting a load on the wheel. in free air that practically does not apply. at speed and under load it might be a different story, but not freewheeling.

fun fact: your freewheel speed is about 15% higher then your loaded top speed. so you need to take that out in the first place. if you are much lower then 15% you need to look for different causes like voltage sag under the load, a inefficient motor and so on.
 
flippy said:
if the wheel is just spinning in air you need just 1A or less to get it going at its full speed. you need volts. amps is only needed for power once you are putting a load on the wheel. in free air that practically does not apply. at speed and under load it might be a different story, but not freewheeling.

fun fact: your freewheel speed is about 15% higher then your loaded top speed. so you need to take that out in the first place. if you are much lower then 15% you need to look for different causes like voltage sag under the load, a inefficient motor and so on.
As above, he doesn't have a speedometer, and so can't use no-load speed to diagnose.
 
rg12 said:
About kelly, yeah but they are pretty big...it's for a scooter with small space.
Kelly controllers are huge upgrade from generic Chinese clones. Check out the KLS84-H models. They're 105V max and will take 24s.

Anyway, it sounds like you don't know motor kV, and can't monitor voltage, current, or motor or wheel speed?
Without those, you can't diagnose anything.
 
fatty said:
As above, he doesn't have a speedometer, and so can't use no-load speed to diagnose.

you can still read the speed from the controller or even tap a signal off a hall sensor or buy a cheap rpm meter of amazon.
 
fatty said:
rg12 said:
About kelly, yeah but they are pretty big...it's for a scooter with small space.
Kelly controllers are huge upgrade from generic Chinese clones. Check out the KLS84-H models. They're 105V max and will take 24s.

Anyway, it sounds like you don't know motor kV, and can't monitor voltage, current, or motor or wheel speed?
Without those, you can't diagnose anything.

These are pretty huge for my use but thanks :)

Current is 36A with load, voltage is 24S, sag is about 1-2V

I suspect a weird rpm limit in the motor...

It has a very weird thing that when the scooter is pushed backwards while the controller is on the motor resists and makes it hard to push backwards (not stopping but slowing down hard) maybe an idea to help while standing in a traffic light on an incline or something but unfortunately it's just annoying.
 
rg12 said:
I suspect a weird rpm limit in the motor...

the motor does not have an rpm limit. it will spin as fast as you give it volts, or explodes from the forces....

rg12 said:
It has a very weird thing that when the scooter is pushed backwards while the controller is on the motor resists and makes it hard to push backwards (not stopping but slowing down hard) maybe an idea to help while standing in a traffic light on an incline or something but unfortunately it's just annoying.

its regen, the same happens if you push foward, the motor works as a generator. or the controller simply shorts out the phases to lock the motor in place. but that is very unusual.

a KLS8422H would serve your needs perfectly.
 
rg12 said:
It has a very weird thing that when the scooter is pushed backwards while the controller is on the motor resists and makes it hard to push backwards (not stopping but slowing down hard) maybe an idea to help while standing in a traffic light on an incline or something but unfortunately it's just annoying.
The generic 15fet on the SB Cruiser trike does the same thing. Rolling the trike forward by hand is easy, but backing it up is quite difficult--if I had both motors using the same kind of controller, it might be so hard as to be beyond my ability.

It also has an antitheft function that locks the wheel in both directions just as hard.

This controller makes my motor whine all the time, faintly, even with no throttle connected, kind of like the SFOC5 by Incememed did, as if it were using a waveform pattern into the phases to help determine if the motor was moving at all (even though it is a sensored-only controller, requiring the halls to be correctly connected to work).
 
fatty said:
rg12 said:
Current is 36A with load, voltage is 24S, sag is about 1-2V

If you're pulling about 3kW, then ~60km/h on a scooter looks about right.
Here's Grim Simulator with 24s and 35A controller showing an upright MTB at ~67km/h. A bit higher rolling and aero load on a scooter would drop to ~60km/h.

Maybe check the other scooter to see what actual current draw is.

It doesn't seem right to me...
Same scooter with 60V 25A gets to 55-60kmh under load with a 25A controller and exactly the same motor.
How come 88.8V at 35A gets to the same speed? it has 50% more voltage.
 
rg12 said:
It doesn't seem right to me...
Same scooter with 60V 25A gets to 55-60kmh under load with a 25A controller and exactly the same motor.
How come 88.8V at 35A gets to the same speed? it has 50% more voltage.


massive switching losses. the controller is not fast enough.
 
flippy said:
rg12 said:
It doesn't seem right to me...
Same scooter with 60V 25A gets to 55-60kmh under load with a 25A controller and exactly the same motor.
How come 88.8V at 35A gets to the same speed? it has 50% more voltage.


massive switching losses. the controller is not fast enough.

Shouldn't it overheat then? it was slightly warm at best
 
rg12 said:
Shouldn't it overheat then? it was slightly warm at best

the little leprechaun inside probably cant switch fast enough and "misses" its switching moments and you get overlap. the heat gets generated in the motor. it must have really shitty mosfets and/or control chip.
 
flippy said:
rg12 said:
Shouldn't it overheat then? it was slightly warm at best

the little leprechaun inside probably cant switch fast enough and "misses" its switching moments and you get overlap. the heat gets generated in the motor. it must have really shitty mosfets and/or control chip.

I don't think that's that...
The motor is cool also, no gittering, super smooth...
I think that just like any controller that it has a the setting for max rpm limited for some weird reason.
 
rg12 said:
I don't think that's that...
The motor is cool also, no gittering, super smooth...
I think that just like any controller that it has a the setting for max rpm limited for some weird reason.

Well, guessing won't really resolve anything, and you're getting lots of good diagnostic advice. You can either start instrumenting to collect data, or switch the controllers to see if that changes anything.
 
fatty said:
rg12 said:
I don't think that's that...
The motor is cool also, no gittering, super smooth...
I think that just like any controller that it has a the setting for max rpm limited for some weird reason.

Well, guessing won't really resolve anything, and you're getting lots of good diagnostic advice. You can either start instrumenting to collect data, or switch the controllers to see if that changes anything.

Yeah I'm looking for a replacement already, got a different chinese one on the way so maybe that will solve it before I find a proper replacement
 
Yeah I'm looking for a replacement already, got a different chinese one on the way so maybe that will solve it before I find a proper replacement
Hello. I also have an Inokim ox super scooter with a stock 60v 21Ah battery and an Asibac 855 controller, which unfortunately failed. Could you tell me which controller I could replace it with.
 
So. What I'm seeing is someone who's already getting 37 mph on a donut-wheeled deathtrap, but wants to become road pizza at a higher speed than that.

I think it's a bad idea to help.
 
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