Nucular electronics - complete kit for ev!

[Merlin]

JESUS :lol:


for NOW: you can limit your 3 Modes to AMPS.....thats what i mean.

Yes you loose speed because voltage goes 15-16v down. But you wouldnt lose speed either wenn you limit to WATTage
but anyway who cares about speed because Bike behavior is same even if you lost 10-15kph on lower battery...your throttle is allready 100% open.


lower rpm should be same?
why we talk now about rpm?

I may be wrong, but I don't think the amps differ from a fully charged to a almost empty battery.

YES! amps are always the same but as your voltage drop ~15v you have not anymore the same wattage.

amps x voltage = wattage
amps(same) x voltage(-15) = less wattage.

less wattage = different ride.



iam so happy that the important guy knows what i mean (vasiliy)
lets go on with other stuff ^^

 

[PITMIX]

ok Merlin thanks for the explanations

 

[Merlin]

no problem. iam always dreaming about "the one" ....the perfect one haha

 

[j bjork]

JESUS :lol:


lower rpm should be same?
why we talk now about rpm?

Why I am talking rpm?
Because that is what it is all about.

You don't want to limit torque (amp)
But you want to limit power. That means you have to limit the rpm where you still have max torque.
Well, not exactly. But the rpm where you still have enough torque to have max power.
To do that you limit voltage, and with that at what rpm you still get enough amps to get enough torque.

Then you can get the same behavior at almost empty battery as with a full battery

 

[Merlin]

sry. you are simply wrong =)

if you want to limit by power you regulate the amps.

 

[john61ct]

Field weakening isn't magical.

I did not mention nor ask about FW, was that somehow implied in the recent post topics? I know little about it, afaik not relevant for my needs (highest possible torque at low rpm)

> I'm not sure how a CA can possibly implement real FW or phase current control. The CA would need direct access to the halls and phases to do this.

Yes, exactly my point, the reason CA is "obsolete" with such modern sophisticated controllers.

Are these features / phrases

"phase current control"
"direct access to the halls and phases"
"hall delay/advance"
"current sensor on each phase connection, directly measure amps for each phase"

all synonymous with true FOC?

> Nucular controllers use shunts on the battery side and some math to calculate phase amps.

In other words, it does not do those above?

 

[larsb]

Are you really ontopic now?

 

[j bjork]

sry. you are simply wrong =)

if you want to limit by power you regulate the amps.

Silly me, who always thought that the voltage dropped when the battery got discharged.
And thought that power was torque x rpm.
And that the amps set the torque and the voltage the rpm in an electric motor.

 

[Merlin]

no problem, you see, you can always learn :lol:

 

[larsb]

Don’t be so nasty merlin. I honestly can’t see what you want to have, don’t think the others understand you either.

You want constant output curve over the entire discharge?

So basicly used voltage will be restricted through the pwm to about 60V for a 72V nominal system and used max current will still be set to your allowed max current setting. You’ll have a constant output over the discharge of the battery, effectively limiting your rpm to 71% of max achievable at 84V. (Power is not constant over the rpm but i still think above is what you want.)

As soon as the rpm is allowed over the max 60V output you’re getting higher power so you are effectively rpm limited in what you describe.

 

[Merlin]

You want constant output curve over the entire discharge?

yes

So basicly used voltage will be restricted through the pwm to about 60V for a 72V nominal system and used current will be set to your allowed max current setting. You’ll have a constant output over the discharge of the battery, effectively limiting your rpm to 71% of max achievable at 84V. (Power is not constant over the rpm but i still think above is what you want.)

no, amps will "restrictred or raised"

Or you want constant power

yes

so current will be ramped down from your max allowed current at zero rpm to noload current at noload rpm with a progressively weaker bike as you accelerate to higher rpm?

no(t) sure what you mean

i dont want to be nasty buddy. but i dont know how to help you understand the "Power/wattage" limit.

forget the option to max/limit the amps.

Controller fits the current you need to reach your wattage limit.
because as you allready know: voltage drops. while discharging, while riding, it sags high on high power or it sags less on low power.
but your voltage varies a l l t h e t i m e.

so: controller allows that amount of current to reach your "setup wattage limit"

for example "S2"

you want 10000w of Juice. From fresh Battery, on pretty low Battery, when its hot outside or cold as frock.

Voltage on starting 84v ...10000w/~80v(drop on sag).............125A needed.
Voltage on middle 76v.....10000w/~74v(drop on sag).............135A needed.
voltage on low 66v.........10000w/~66v(drop on sag).............150A needed.

controller would not even "need" an amp limit(inside specs)

voltage varies from using the battery
amps varies because voltage does.

output until LVC = 10000w

 

[ElectricGod]

You could set battery amps in the controller to whatever is the best you will get when the pack is discharged so you don't get sag.
The phase amps could also be set low enough to not cause sag.
Riding around like this would guarantee that no matter what the pack charge level is, motor torque would always be the same.

Motor RPM = Kv x Voltage
AKA the motor runs faster on more voltage and slower on less voltage.
You could set the 3 speed option to reflect the voltage of the pack when nearly discharged.
The 3 speed option allows you to set motor RPM.
Set it to the maximum RPM possible when the pack is run down.
Now the motor, regardless of charge level or pack voltage, always has the same maximum RPM.

With both of these set, no matter what the charge level is, torque and motor RPM are always the same as what you would get when the pack is nearly depleted. No idea why I would EVER do this for regular use, but yeah...totally doable. I guess an endurance race might use this?


1. In simplest terms, motor torque at 20v or 200v is dependent on the amps in the phases. More amps = more torque. Less amps = less torque.
2. Voltage is what gives the motor it's maximum RPM. The motor Kv X pack voltage = motor RPM. More voltage means a higher top motor RPM.
At 20v and a 100kv motor, that's 2000 RPM max
At 200v and 100kv, that's 20,000 RPM max

How RPM plays with torque is pretty simple.
The motor generates its full capability of torque based on the phase amps.
As the motor gets to about 80% of full RPMs, you feel the torque or ability to accelerate equally hard starting to drop off a little.
The closer you get to that maximum RPM possible, the less you feel the motor torque and acceleration.
The motor didn't stop making torque, it just can't make more RPM's and still make torque at more RPM's.
Eventually you feel the acceleration stop and your EV stops accelerating further.
It's still making pretty much the same amount of torque, just not more RPMs.

 

[larsb]

It's still making pretty much the same amount of torque, just not more RPMs.

@ EG: No. Can’t be bothered to link anything but i urge you to look at any torque-speed curve. Is torque constant at higher rpm?

if you want to limit by power you regulate the amps.
...
controller would not even "need" an amp limit(inside specs)

@merlin: No, this cannot be achieved over the full rpm range. At higher than max voltage/speed (for instance at 60V compared to 84V) you can’t get the amp out at all. So controller will effectively be max phase voltage (rpm) limiting to have same output curve for two input battery voltages.
Second thing is that if you’d play with current like your example to have constant output power towards an imaginary setpoint then controller would make your bike run away.

The power output will match the load condition, not a set power limit

I’d be happy to continue this in another thread but let’s not spam the Nucular sales more with this topic

 

[madin88]

iam so happy that the important guy knows what i mean (vasiliy)

:lol:

It makes perfectly sense, especially if you have speed limits set (or enough RPM in reserve), you hardly would notice a difference in acceleration or power over the entire state of charge. The only not so nice thing would be that discharge curret will increase at lower voltage.

 

[larsb]

Problem is that the important guy hasn’t said it can be done. With rpm limiting yes, away from max rpm yes
But it’s not power matching aV*2bA to 2aV*bA that’s done.

 

[madin88]

But it’s not power matching aV*2bA to 2aV*bA that’s done.

Why not?
Lets take as example a setup with 20s battery which is set up as following:

max batt amps: 100A
max phase amps: 300A
max speed: 80kmh

with above settings, the max power at 100% SOC would be 100x84V = 8400W, and at lower SOC like 70V it would be only 100x70V = 7000W.

Now lets imagine you could set it up as following:

max power: 8400W
max batt amps: 140A (-> to be able to pull 8400W down to 60V)
max phase amps: 300A
max speed: 80kmh

With above settings you would have quasi identical power and acceleration from 100% to 0% SOC.
It is assumed that your motor doesn't run out of RPM, because if it does then of course your top speed would be less and also acceleration at higher speeds (field weakening left disabled).

Just imagine that you have street legal e-moped like Surron or LMX, which are limited to 3000W / 45kmh in your country, wouldn't that be a nice option to have?
At only 45kmh you definitely have enough RPM in reserve on those bikes so you would not feel a difference in acceleration at all between 0% and 100% SOC.

 

[larsb]

But there’s a constant torque region up to where the current cannot be reached anymore due to BEMF. Here the systems are the same no matter what battery voltage up to where the lower battery voltage sets the limits. (Output power in this region with fixed current is proportional to rpm and not constant.)

As soon as the voltage limit is reached, systems are not the same, cannot be the same without rpm limit.

Phase current sets torque, right? Increase this to meet lower battery voltage to keep power the same and your bike will run away compared to the lower phase current and higher batt voltage discussed.

 

[csc]

Hi guys

I'd like to send more juice to my rear qs273 "4000" when I start and at low speed. Bigger kick, in other words. There's a kind of software based, progressive acceleration that I'd like to turn into brutal

I have a consistant margin concerning sag and motor + 12F temp, there's some watts left

What settings would you use ? Clutch stuff ? Of course the phase and battery amps are already set at max

Sorry if the answer is above, I have to read the whole thread, as the question seems to be in discussion

 

[john61ct]

power limit option for each mode.

we all know how nice is the first miles with a fresh battery. and we all know how it sucks when your on 30% Battery left.
you miss some couple KW of Power because your Battery voltage drops 15/16v.

if you had the option like on the old cycle analyst setting a power limit you could open the amps in all modes fully and only limit your modes to power. Voltage drops, power stay same from first to last mile your bike feels all the time same.

Reading the github wiki for the KT FOSS firmware

Power Based Control: Switches from current regulation control to power regulation (the lower voltage the more current you get for the same assist %)

Am I right, that's what you're looking for?

If they can do it, I'm sure V can, if he wants to. . .

 

[john61ct]

I see "Power limit for modes" has been added to the future feature list.

http://nucularelectronics.wikidot.com/en:bugs-and-features

 

[Merlin]

yes

yes

and yes. i talked with vasiliy in his group about. iam not the first who had this on the wish list.

 

[larsb]

So, this is interesting :wink:
What happens above max rpm for the discharged battery (say 60V*kV rpm for a 72V system) when battery is at 60V?

How does the constant power output take rpm up to 84V*kV?

 

[john61ct]

At some point need to either compromise or just accept the trip is done.

Limp home mode?

 

[ElectricGod]

At some point need to either compromise or just accept the trip is done.

Limp home mode?

Just make a 3 speed option that is very low power. That's limp home mode.
We all hate having to walk home, but hey we all run our packs out too sometimes.

 

[ElectricGod]

Hi guys

I'd like to send more juice to my rear qs273 "4000" when I start and at low speed. Bigger kick, in other words. There's a kind of software based, progressive acceleration that I'd like to turn into brutal

I have a consistant margin concerning sag and motor + 12F temp, there's some watts left

What settings would you use ? Clutch stuff ? Of course the phase and battery amps are already set at max

Sorry if the answer is above, I have to read the whole thread, as the question seems to be in discussion

I think if you already have phase and battery amps set to max, you are at the limits of the controller.
A throttle curve will help with low down grunt some, but whatever is your maximum motor torque now is not going to change.
Whatever "untapped watts" you might have left are not going to be accessible without a more powerful controller.
It may be that there is a way to unlock the 12 fet so you can manually set battery and phase amps higher than they are limited to now.
The controller can handle more. I recently ran a PowerVelocity 12 fet at 7kw continuous. I got it to 8kw and that's when it burned out.