Aussie EV Autocross Special

I got it at a garage sale. I might see if it would work on the front. It would have a better chance of making a difference up there.
 
I did this trial run of a cheepo 360 degree camera on my EV. Still a work in progress. Seems sensitive to the light conditions at the time you push the button. I need to work out how to get it to work properly.

I just realized the pole I am using to raise the camera above the car makes it look like a bumper car :)


I won't embed the video because it really only works on a mobile device.

http://www.youtube.com/attribution_link?a=6wB51xixUek&u=/watch%3Fv%3D3iffletOSNg%26feature%3Dem-upload_owner
 
It's been too long between events. But the next one is looming large now. It is a motorkhana on this Sunday Aug 7 at Willowbank. If anyone local to Sth East QLD is interested please come along. Spectators are free. I am confident I am past all my teething problems and I am expecting a better indication of how competitive the car can be. I am litterally expecting 30-40% better power. But obviously grip is a variable that will limit my ability to use the power. But I have introduced launch control and put wide slicks on the front. Either way it will be exciting. Hopefully I will have some good videos to share early next week.

Then the following event is another motorkhana. But then the final event for 2016 is a khanacross on Nov 7th. My car is much more suited to Khanacross so I am holding on to the hope of reaching first place in class and even first place outright at this event. But that is an optimistic goal given the jump from 2nd in class and 10th outright at the last khanacross.

This weekend I intend to do a couple of sneaky speed tests to see if my latest improvements are having the expected impacts on 3rd and 4th gear acceleration. From these tests I will have a much better idea how it will go in November.
 
A friend suggested I should blog all the teething issues I have faced since the car has been competing. So here goes:

Feb 7th was a motorkhana. The car wasn't too bad at this event although I hadn't turned the controller all the way up and the controller delay was a pain making it a handful to drive. I have since turned the controller all the way up and removed the delay.

Feb 21st was a khanacross. The old AGM batteries were not up to the task. I was only able to complete 60% of the event. I also destroyed two of the AGM batteries which split their seams and were venting acid out the sides. The ackerman angle was still wrong at this point so the car was fighting itself in high sped corners.

March 19 was a motorkhana. I had swapped over to the Lilo batteries from a chevy volt. The batteries were fine but I did not have a method of charging them. I travelled 10 hours each way knowing I only had 145volts. It only lasted 20% of the event. But was otherwise running fairly well.

April 24 was a motorkhana. I only managed 1.5 runs before I broke my brakes (broke the weld connecting the pedal to the master cylinder). I managed to complete the second run using the handbrake but decided it was not a great idea to continue for the rest of the day.

May 25 was a Khanacross. I had a loose connection for the first 2 runs. The car actually stalled completely on the second run. I found the issue and the car was promising for the remaining runs of the day. I managed 2nd in class and 10th outright. After the event I realised the brushes were seized in place and the motor was beginning to arch.

But I have now wound up the controller to the max and solved the issue of the brushes. So I am confident the results will improve in khanacross. Motorkhana will always be challenging for this car as it is wider than the other motorkhana special cars so it is at a disadvantage in most motorkhana courses. The torque of the electric motor will compensate for the width to some degree but whether it is enough is yet to be seen (Starting with this coming Sunday).
 
Ok so that didn't go to plan!!

The car survived the day but was mediocre at best. The driver has a lot to answer for. In hindsight when it broke so early at the previous few motorkhana days it limited my ability to learn the car. So yesterday that lack of knowledge finally became apparent. More time behind the wheel will fix that.

But the performance is still an issue. Before the event I had the chance to take it for a test drive down the 1/4 mile drag strip. I saw absolutely 0% improvement compared to previous events!!!
I was/am perplexed. I have the controller turned up fully and I fixed an issue with siezed brushes. How could I not be seeing any improvement at all. This was the first time I have had the chance to test for absolute top speed (not having to slow for corners etc. I did not manage to get more than 90kmph. It's pretty obvious something is wrong. This motor and controller should be able to do that with a car 3 times the weight.

I have a few theories.
Maybe I am seeing a recurrence of the siezed brushes. I am not sure how that would be possible but I will check anyway. Its unlikely to be the brushes this time but it could be a problem with one or more of the springs.
Maybe my accelerator pedal is not giving the correct resistance. Again in theory it is correct but I might try adding a resistor in series to bump the resistance up by 1Kohm.
Maybe I have a weak point in my conductors. I will try doubling up some of the conductors in some obvious areas to see if I can eliminate any weaknesses. I had been operating under the assumption that the conductors would be getting warm if they were not up to the task. But maybe they are up to the task 95% of the time and the 5% when I need full current is not long enough to get them warm.

[youtube]RuSLeiFATzU[/youtube]
 
Are you still operating without a CA and a CA Logger? If so, that is your problem. Until you can study and evaluate what your speed, amps, and volts are doing at all points, you will have no idea what is going on. You can't diagnose a problem if you can't evaluate it properly.
 
I have been ready to purchase one as soon as a vendor has the appropriate product available.
 
I have had a thought.

When I initially put the car together I got the rotation direction correct first time. I never considered the need to check if the brush timing was set for that direction.

I have been getting some arcing, but only at highish revs. So I have been avoiding high revs (as I need to anyway with a big DC brushed motor).

But hypothetically if the timing was set for the oposite direction I am assuming that would impact the ability for the motor to deliver power?

Is there an easy way to check without zapping myself. I have seen a few threads on the matter but none seem achievable to me. eg most require running the motor under load and being able to see the brushes etc.
 
When I took the end of the motor off a few weeks back to maintain the brushes I did notice there were three sets of bolt holes. But I figured the factory much have got it right so I stuck with the way it was. In hindsight the factory may have set it up to spin the other way. But anyway I figure it shouldn't be too hard to tell from the bolt holes whether it was advanced or retarded.

I also saw a post that said you loose 2% torque for every degree the timing is out. if it is reversed it is likely 20 degrees out = 40% reduction in torque. That is exactly how it feels.

I'll give an update in a day or two.
 
Only on full throttle for around 1/10 of a mile or 250m. Don't criticism me if these aren't the same distance I haven't bothered doing the math because I didn't measuring it anyway. I did video it, I'll post it when I get a chance.

I was half right the brushes were set in the neutral position. I have now advanced them by what looks to be 10 degrees. I wasn't sure which way was advanced so I checked Youtube. I hope what I saw there is accurate. I moved the brushes in the oposite direction to the armature rotation.

I did another driveway test but as usual it is too short to determine if I have any more power. I still have a few other things to check so we'll see what I can come up with.
 
By the way I have now created a new Youtube channel and Facebook page. Feel free to check them out here:

https://www.youtube.com/channel/UCnE...ehgrxXcohzWiYQ
https://www.facebook.com/fullchargemotorsport/
 
galderdi said:
By the way I have now created a new Youtube channel and Facebook page. Feel free to check them out here:

https://www.youtube.com/channel/UCnE...ehgrxXcohzWiYQ
https://www.facebook.com/fullchargemotorsport/


Hey mate your you tube channel doesn't exist :|

Cheers Kiwi
 
https://m.youtube.com/results?q=full%20charge%20motorsport&sm=3

oopps. Thanks for that. Try this one
 
I have just purchased a Cycle Analyst. Now I just need to wait for delivery. However my next event is sneaking up fast so I am not game to add a new component unless a I have some time to test it etc before the event. We will see.

I did some more work on the car over the weekend. I did some tests including a start from 0 in 2nd gear. It was not great. It boggs down until it gets a little more speed/revs then the acceleration kicks in again.

But this got me thinking. It accelerates from 0 in 2nd gear very similar to 3rd gear at 80kmph. It makes me think maybe the revs are the problem. Until now my revs have been somewhat limited because my brush timing was neutral. So I was changing from 1st to 2nd and 2nd to 3rd earlier than I should (in theory). So in theory if I had time to wait for it to rev up a bit more it might actually improve some more. But I haven't had long enough straights to proove that. Now that I have adjusted the brush timing I am thinking I should be able to hold the gears longer and enable me to put it in gear in the sweet spot without it bogging down.

This seems right to me based on what I am feeling. But the theory sounds wrong for 2 reasons:
1) I would have expected it to have enough torque to pull through the higher gear
2) The gearing has not changed from the original donor car. The donor car didn't rev that high, probably about the same as the electric motor, maybe 5000 rpm. When racing the original car I was running through the gears similar to the rate I am running through them now. In other words I would not have expected my gear changes to result in the revs being too low. I think I need a tacho!!! Any ideas how I can add a tacho to the motor?

But then I see some example torque curves and they show the curve starting at 2500-3000 RPM. That would support my theory.
 
"Bogging down" a Elec drive from standstill untill the revs increase sounds very odd !
You should be getting maximum torque from zero revs.
It sounds almost as if you have a "soft start". torque limiter function working in that controller ?
Really need that instrumentation to see what is happening.
 
Hillhater said:
"Bogging down" a Elec drive from standstill untill the revs increase sounds very odd !
You should be getting maximum torque from zero revs.
It sounds almost as if you have a "soft start". torque limiter function working in that controller ?
Really need that instrumentation to see what is happening.

Thats not a listed feature. But it could be a symptom of a problem in the controller.
I still have a couple of other things I want to double check. I'll give another update when I know more.
 
galderdi said:
Hillhater said:
"Bogging down" a Elec drive from standstill untill the revs increase sounds very odd !
You should be getting maximum torque from zero revs.
It sounds almost as if you have a "soft start". torque limiter function working in that controller ?
Really need that instrumentation to see what is happening.

Thats not a listed feature. But it could be a symptom of a problem in the controller.
I still have a couple of other things I want to double check. I'll give another update when I know more.

What type of throttle are you runing?

Cheers Kiwi
 
Its a fly by wire pedal from approx 2008 Mitsubishi Lancer. I have double checked the controller manual and the actual resistance from the pedal.
The controller manual recommends a 5k pot but then it talks about the start of the range kicking in at 400 ohms and top of the range at 4500ohms. It should only trigger a safety cutoff at around 7k
The pedal gives 800ohms to 4700ohms. But I am consious that maybe in reality the controller doesn't max out unless it sees the full 5000ohms. So even though the pedal should be ok I have some pots that I will try if all else fails. I am fairly confident I can rig it up in the same housing as the lancer pedal so it will bolt in easily.

I also want to double check the current limit on the controller. I did turn it up. But I can't see in the controller to confirm visually. I will try my endoscope to see if I can get a better view.
 
galderdi said:
Its a fly by wire pedal from approx 2008 Mitsubishi Lancer. I have double checked the controller manual and the actual resistance from the pedal.
The controller manual recommends a 5k pot but then it talks about the start of the range kicking in at 400 ohms and top of the range at 4500ohms. It should only trigger a safety cutoff at around 7k
The pedal gives 800ohms to 4700ohms. But I am consious that maybe in reality the controller doesn't max out unless it sees the full 5000ohms. So even though the pedal should be ok I have some pots that I will try if all else fails. I am fairly confident I can rig it up in the same housing as the lancer pedal so it will bolt in easily.

I also want to double check the current limit on the controller. I did turn it up. But I can't see in the controller to confirm visually. I will try my endoscope to see if I can get a better view.

Can you change to hall and map the output with controller, on my sonic I have full throttle at 3.85 volt instead of 5 volts this gives a short responsive pedal and quick acceleration.

Cheers Kiwi
 
kiwiev said:
Can you change to hall and map the output with controller, on my sonic I have full throttle at 3.85 volt instead of 5 volts this gives a short responsive pedal and quick acceleration.

Cheers Kiwi

The controller doesn't support that option.

The bad news is that everyday it seems more and more likely I will need to replace the controller. I just don't have the funds to do that so I will likely just have to put up with it for a year or two.
 
Or add a large relay that bypasses the controller. Kind of like a turbo button. first accelerate through the controller, then bypass it and you know that you are getting 100% juice to the motor
 
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