Faking throttle for torque driven controller

[nuxland]

I have a 10kw motor and 250A controller installed in go-kart. Controller is VEC500 and motor HPM10kw air-cooled.
I want that battery current is limited to 200A but in the same time want to be give 250A when needed for short period.
I can not use 250A all the time because motor will overheat after 6km of racing (it is 6 laps, but race is for 10 laps).
In controller software there is only one battery limit value and my plan is use there 250A and then lower throttle maximum
voltage from 4V to 3V. My assumption was that then controller will give 20% less current when full throttle.
But in the real word controller still used maximum battery current, even if voltage from throttle was 3V.
I'm using "hall effec throttle" and have wired a button that will bypass voltage divider to get 4V from throttle when needed.
But 3V or 4V from throttle to controller did not make any difference. In controller software throttle range is 0,5V to 4V.

Have anybody used this kind of approach for any success? Or how can I achieve what I want?
Golden Motor MagicPie 4 should have similar controller.

 

[riba2233]

It will work, but only if controller has real torque control.

 

[nuxland]

It is not working with Golden Motor VEC500 controller right now
Does this mean that GM controllers have some kind of fake torque control?
Maybe throttle parameters are wrong? I tried today with 2V throttle output and results are the same.
Here are my throttle parameters:

 

[nuxland]

It is deffinitly not speed based throttle, because wheels off ground it will go to full speed, even with 15% of throttle.
And you can not alter the speed of motor at all, like on and off only.
Actually I have not driven with half throttle because it is a go-kart but will try how the trottle responds in range.

 

[steveo]

It is deffinitly not speed based throttle, because wheels off ground it will go to full speed, even with 15% of throttle.
And you can not alter the speed of motor at all, like on and off only.
Actually I have not driven with half throttle because it is a go-kart but will try how the trottle responds in range.

I wanted to ask how do you like this controller?

I'm looking to purchase one for the 5kw inrunner golden motor that will be used for outboard boat motor..

does it run hot under heavy load? what is the peak kw you have seen from it?

i'm considering to buy a controller that can do 5-10kw continuous without melting and reliable..

love to hear your feedback.. any pictures of your cart?

-steveo

 

[nuxland]

Pictures are here: http://endless-sphere.com/forums/viewtopic.php?f=34&t=68543
for 10kw the controller is a little weak if you want to use more that 10kw.
I have installed extra sink behind the controller because it overheated with 12kw constant driving. But after the sink I can use it to drive with 15kw, but no more because 48V controller can only use 300A max battery current.

What puzzles me is configuration option "Starting Phase Current". If I put there 500A then reaction is very good but I can not drive at low speed, it's like on and off throttle then.
When controller is using this "Starting Phase Current"? Every time I release throttle and then press it again? Or only from 0 rpm?

 

[steveo]

Pictures are here: http://endless-sphere.com/forums/viewtopic.php?f=34&t=68543
for 10kw the controller is a little weak if you want to use more that 10kw.
I have installed extra sink behind the controller because it overheated with 12kw constant driving. But after the sink I can use it to drive with 15kw, but no more because 48V controller can only use 300A max battery current.

What puzzles me is configuration option "Starting Phase Current". If I put there 500A then reaction is very good but I can not drive at low speed, it's like on and off throttle then.
When controller is using this "Starting Phase Current"? Every time I release throttle and then press it again? Or only from 0 rpm?

my motor is meant for 5kw continuous and i think 7kw peak -- and... its water cooled.. this controller would work fine .. even though its not the greatest on your application... you over heating was past 10kw .. so that answers my question.. overheating does occur if pushed past its rated specs...

why did you not buy the vec500 96v version?

sound like you bought the vec500 48v right?

thanks for letting me know the issues you have had.. it can help me to make a decision on which controller i will burn my money on!!

-steveo

 

[zombiess]

What puzzles me is configuration option "Starting Phase Current". If I put there 500A then reaction is very good but I can not drive at low speed, it's like on and off throttle then.
When controller is using this "Starting Phase Current"? Every time I release throttle and then press it again? Or only from 0 rpm?

Try changing your throttle from linear to exponential, that should help with start up and low speed.

For safety I would enable the throttle range protection, otherwise you could run into a stuck throttle issue. All it takes is the ground wire to become disconnected and you could end up at full throttle... not fun.

Accell and Decell act as a buffer/low pass filter to minimize rapid small throttle changes.

Running high phase amps can cause your motor to overhead more quickly. A balance between phase current and battery current should be worked out. A few of us on here have found running high battery current and lowering the phase amps provides good mid range and top end performance but sacrifices some dead stop low speed acceleration.

If you have not ventilated your motor yet, it might be a good time to do so. If the motor is overheating, you could setup a fan and a misting system to spray distilled water into the motor to cool it.

I can't find any tech info on the controller, just sales stuff. Does it support field weakening? If so are you using it? This is another area you can tune to improve performance if the controller has this option. With it, you can extend the usable RPM range of your controller. This means you can gear the kart mechanically shorter for quicker accleration and then use the field weakening to make up the difference for top speed. A lot of this depends on the track you race (open/tight course). The course in the video looks pretty open, but that also depends on the number of other racers and how bunched up you guys get.

 

[John in CR]

How you ride can have a big impact on motor temps, use a CA, temperature gauge, and maybe even a data logger to get a good feel for what creates the heat. You'll probably find small style changes can make a big difference in heat without costing much time. Also look at lowering the current limits slightly. Heat in the copper goes up by the square of current. Plus resistance of the copper goes up by 30-40% comparing a cold motor to a hot one, so heat for a given level of performance increases by the same proportion.

What about ducting more directed at the motor, along with the use of a centrifugal fan blade on the drive shaft? Toolman2 used a 70W leaf blower to force more air around and thru his motor, and he calculated a 1000W savings that would have gone to heat. Then there's also motor mods too. Heat is a formidable enemy, but beating it is pure physics, so take motor ratings with a grain of salt. They're pretty much meaningless AFAIC, because a motor's true limits vary with use, installation, and even ambient temperature.

Don't forget gearing. The lower you can gear a motor, the less stressed it will be. If you're geared for a top speed greater than you use, that will create a lot of unnecessary heat.

 

[nuxland]

Will try with a forced cooling I installed yesterday.

I have reduced gearing because next race is on slower track.