ASI dosent give more than 10kw on motor

MXE

1 mW
Joined
Jul 5, 2022
Messages
14
Hi,

I do have a ASI BAC 8000 with a QS13890H Motor

72v battery

In the bacdoor there are 23000KW rated motor power on setup, but on loggin the motor only brings 10kw

I do have checked motor temp foldback, controller foldback, racepower watts are correct, the display with his stages is out (so for sure no foldbacks there).

So looks all limits are good, but the motor only take 10KW,

Any ideas? Which limitation could limit the power?

Battery/BMS are good, no cut out`s....

Best regards, Breth
 
What display are you using?
Depending on how it works, power could still be limited is it was set to limit before switching it off.
Which winding has your motor?
What did you set phase amps to?

Do you use the BACDoor app to log?
Are the values for motor and battery current in the negative? If yes, you need to correct them (I could explain you how to do that) or just calculate Amps*Volts instead.
 
Hi Hias,

The Display im using is the UKC1. But i did remove the assist mode on the controller, so that they wont limit somthing.

I dont now wich winding the motor has. Its a QS138 90H

Motor current (amps) is 600

Yes i did the bac door log, and yes the "motor input power" is in negative (-10770) is what i see.

Best regards
 
This is normal and because if an internal parameter (rated motor current * rated voltage)>32767 it rolls over to negative.
You can add a new column to your excel file where you correct for that rollover or simply calculate the Power by calculating amps*volts.
However it's no problem that the power is shown incorrectly.
Some other displays like the Eggrider will display the power correctly.
 
if its not a problem for my power-problem i dont need to correct.
 
For me it feels like somwhere is a limitation of power. But all limits are off, as i write in the first post. And if the display assist mode is off, the display cant limit the power either.
 
Just log battery voltage and battery amps instead of power and calculate the watts=amps*volts.
If all limits are off, you need more voltage under load or to rewind the motor with less turns to push more power through it.
 
yeah but the combination of th qs13890h motor with the asi bac8000 and 72vbattery is a commend combination wich shoud easy draws 32kw. So i guess somthing is wrong with the tuning on the controller
 
Why should it be able to pull 32kw at only 20S li-ion and while only using 600 phase amps?
I know somebody with this combination and he draws almost 30kw controller input power, (about 28kw controller output power) from a large 20S27P vtc6 cells pack and phase amps set to 700 or 750.

If you have set max phase amps to 600 and rated voltage to 72V, then your correction factor for the power would be -1.934.
So -10770 were 21kw controller output power in reality.
What was your battery voltage at that moment?
 
My Battery is 20s, 14p with samsung 40t Cells, got 4kw.

phase amps could set at 700.

i didnt loged the volts from battery.
 
That will give you more torque in the lower rpm range and probably also a few kilowatts more peak power.
To improve torque/power in the higher rpm ranges however, you need more voltage under load.

For your setup, I would say 21kw controller output power is completely normal.
When increasing phase amps, also raise the battery power limit to make sure it's not limiting. Same for the battery current limit and all other foldbacks.

If you want 40kw or something like that, Sevco Gen 4 Size 6 and a 28S battery would be an option, but the motor will probably overheat quickly at full power.
 
yeah but it dosent bring 21kw, only 10kw.

And funny thing is that we have a other bike, same battery, same controller, but we do use the qs13870h motor (smaler) on this one, and we do have a lot more power on track. i wasnt log, but it feels like twice the power.
 
Everybody that uses a BAC4000 or BAC8000 where (rated motor current * rated battery voltage) is bigger than 32767 will have negative values for power shown in the log. As already explained this is because an internal parameter rolls over after 32767 because only 2 bytes are reserved for it.
Same as what happens with vehicle speed. After 128 kph it will go to -127 kph. (only 1 byte reserved)

So don't worry, when it logged -10770, it measured a bit less than 21kw controller output power at that moment.

But you can ignore this. Just log current and voltage instead or apply the correction factor (only valid for rated voltage 72V and rated motor current 600A).

If you want to stay at 20S, rewinding the motor with less turns would be an option, but you would need to increase phase amps further to not lose some torque.

If you just make a motor bigger that does not mean you can push more power through it at the same voltage.
This could be the case, but it could also be the other way round as well.
It will be able to handle more power without overheating, so you can operate it at a higher voltage which will give you more power.
 
Hey thank you for your answer. Because im from switzerland i have sometimes a bit problem with understanding everything in english, im sorry.

So means that those 10kw i log what the controler reads means 21kw in real world. Do that also means when i set the 21kw on the controler higher i would have more power?

I understand that power comes from battery in voltage and amps, but in this case i was wondering why the bike feels so slow with a simalar setup to many others with this 72v battery. And im using 280pcs 21700 samsung 40T cells with cooper connectors and big BMS, wich shoud do a good job how i think.

I did rode a other bike with same motor and 72v, but that one felt a lot faster. So thats why i guess its something in the tune wich isnt correct.
 
I have no idea about its own internal logging, but you should be able to really see >20kW power draw from your pack from an BAC8000 that's setup correctly.

The way that it wouldn't be able to drive much power while still maintaining max phase current is if the motors winding kV is so high that it can't get phase voltage up near pack voltage from BEMF as the motor is at high speeds.
 
MXE said:
So means that those 10kw i log what the controler reads means 21kw in real world. Do that also means when i set the 21kw on the controler higher i would have more power?
It did not log +10kw, it logged -10.8kw. I already wrote the reason why this happens a couple of times here.
An again: Yes, when it wrote - 10.8kw it measured a bit less than 21kw controller output power at that moment.
If you are from the Germany part of Switzerland, you could also write me a private message in German.
 
MXE said:
yeah but it dosent bring 21kw, only 10kw.

And funny thing is that we have a other bike, same battery, same controller, but we do use the qs13870h motor (smaler) on this one, and we do have a lot more power on track. i wasnt log, but it feels like twice the power.

The gearing is about the same on those bikes?
What kind of bikes, weight?
 
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