Electric kart

Electric cars, trucks, ATVs, NEVs - things bigger than a motorcycle.
Hillhater   100 GW

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Re: Electric kart

Post by Hillhater » May 04 2016 5:02pm

So, which cells did you use in the end ?
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nuxland   100 W

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Re: Electric kart

Post by nuxland » May 05 2016 4:01am

Hillhater wrote:So, which cells did you use in the end ?
A123 20Ah and I think B grade in 32s2p configuration :)

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nuxland   100 W

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Re: Electric kart

Post by nuxland » May 07 2016 10:54am

Finally got to the racetrack and it is totally different beast now with the new battery and controller. Motor is the same and it seems I can not get more out of it because of the fact, that it is 48V motor and 700A phase current to motor is max. I need to upgrade to 96V motor that has twice the torque for the same amout of current :)
Anyway here is the video also: https://youtu.be/-bWF5UNaJrc
In the video I had already raced 6 laps, thats why controller and motor temp are so high.
Last edited by nuxland on Jan 15 2018 2:38am, edited 1 time in total.

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riba2233   1 MW

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Re: Electric kart

Post by riba2233 » May 07 2016 12:18pm

nuxland wrote:Finally got to the racetrack and it is totally different beast now with the new battery and controller. Motor is the same and it seems I can not get more out of it because of the fact, that it is 48V motor and 700A phase current to motor is max. I need to upgrade to 96V motor that has twice the torque for the same amout of current :)
Anyway here is the video also: http://bit.ly/1WgAztt
In the video I had already raced 6 laps, thats why controller and motor temp are so high.

That wouldn't make sense because they both have the same power. Yeah, twice torque, but half the rpm. Remember, power = rpm x torque. If you want more power, raise the rpm (I think the 6000 is limit for rotor, maybe you could do some custom work to reinforce it), and gear down. That's the only way, along with better cooling.

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nuxland   100 W

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Re: Electric kart

Post by nuxland » May 07 2016 1:44pm

riba2233 wrote:
nuxland wrote:Finally got to the racetrack and it is totally different beast now with the new battery and controller. Motor is the same and it seems I can not get more out of it because of the fact, that it is 48V motor and 700A phase current to motor is max. I need to upgrade to 96V motor that has twice the torque for the same amout of current :)
Anyway here is the video also: http://bit.ly/1WgAztt
In the video I had already raced 6 laps, thats why controller and motor temp are so high.
That wouldn't make sense because they both have the same power. Yeah, twice torque, but half the rpm. Remember, power = rpm x torque. If you want more power, raise the rpm (I think the 6000 is limit for rotor, maybe you could do some custom work to reinforce it), and gear down. That's the only way, along with better cooling.
Actually I have configured the motor in SEVCON as 52V motor and SEVCON gives only 56V to the motor (thats the reason battery amp are so low). But SEVCON-s maximum phase amps is 550 and can be 120% of that for one minute, so its 660A. If I install 96V motor, actually I was thinking for REVOLT rv-160 with 50kv then I will keep the same rpm what I have for my current motor, thats around 5000rpm, but kt is a lot bigger :)
GM 48V 10kw motor kt is 0,106 Nm per Amp, but Revolt's is around 0,190 Nm per Amp.

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riba2233   1 MW

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Re: Electric kart

Post by riba2233 » May 07 2016 3:12pm

Ok, in that case you will have to have around half the current and double the voltage to get same power for revolt, it means 96 V and 330 A instead of 48 V and 660 A for golden. Can 50 kv revolt stand that much current? You can see opened up revolt in another topic, it looks like it has pretty low copper fill and would need to be rewound to have useful performance. Also, since point of this is that you want more power, you would have to use even more current for revolt.

Golden motor has more copper and thermal mass, and you can get more power from it by raising rpm, after reinforcing rotor. I think that that wont be a problem for someone who is good with lathe.

This are just my thoughts, I like the revolt but I think it should have better copper fill, and I don't think you can get much more power from it comparing to large golden.

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nuxland   100 W

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Re: Electric kart

Post by nuxland » May 19 2016 8:30am

Golden can also tolerate 600A for seconds and not minutes. But the benefit using 96V motor that has twice the torque per amp is that controller is not heating up so fast (lower motor current) and also motor should not heat up so fast as there is lower current to the motor :)
Here is a image when there was max power to the motor (it started to lower motor current from 3000rpm)
Also there you can see that cell 32 is 0,1V lower than others. As I have 2p32s configuration then I think one of the paralel cells is weaker. Can someone know how to check whitch one if bad if I would remove them from the pack?
MaxAmp.png
And here is the graph, what will that current do to the temps :)
Motor_Controller_Temps.png
Motor_Controller_Temps.png (121.17 KiB) Viewed 3290 times

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nuxland   100 W

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Re: Electric kart

Post by nuxland » Jun 22 2016 4:21am

Have installed watercooling to the controller. Will see how well it performes in the race we have in sunday with two other electric karts and Retro(Sojuz/CZ) karts.
There is a 5mm thick aluminium between controller and heatsink that has waterway cut in. Cold water enters through the heatsink and exits through the controller.
WaterCooling.jpg
WaterCooling.jpg (113.79 KiB) Viewed 3221 times
WaterCool3.jpg
WaterCool4.jpg
Here already installed:
WaterCool1.jpg
WaterCool2.jpg

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nuxland   100 W

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Re: Electric kart

Post by nuxland » Jun 24 2016 4:56am

This is how the data are aquired during races. There are three thing that are recording data in kart.
1. Analogger (records basic data and motor exit air temp and controller extra heatsink temp).
2. Olimex stm32 development board (records every can packet that is transmitted in canbus to binary file) also displays importat information in 4 line lcd screen. And relays all the can packets via bluetooth to android.
3. Windows application (records pre defined canbus packets to human readable txt file) also displays all that data on screen and sends the data via internet to server for live viewing.

For battery monitoring I'm using Zeva BMS boards that are sitting in canbus so both olimex and windows application can get the data.
Then there is android application that displays motor and controller temperatures (these I can actually see during the race, others are too small) and other data.
And for remote viewing there is web application using SignalR to display realtime information in a webbrowser. During the race I have a friend at home looking this and telling information via handsfree to me :)

Live info (battery is charging, thats why negative current)
LiveInfo.jpg
LiveInfo.jpg (82.94 KiB) Viewed 1423 times
Android and cycle analyst and clearview
Wheel.jpg
Olimex and Zevas
OlimexAndZevas.jpg
Windows tablet
WindowsApplication.jpg
Video is rendered afterwards with Racerender, it delivers everything I need. Can have multiple source files for data and multiple videos also.

Here is the live info link also: http://jumpware.eu/karts.html
Race is on 26th of june, there are three races for each class. retro one-s are at 13:20 14:40 and 16:00 local time in Estonia.
Last edited by nuxland on Jun 24 2016 11:11am, edited 1 time in total.

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Arlo1   100 GW

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Re: Electric kart

Post by Arlo1 » Jun 24 2016 9:28am

Wow great work Nuxland
My Leaf motor controller build. viewtopic.php?f=30&t=63982&p=963227#p963227
My YSR build http://www.youtube.com/watch?v=BRo8r5g4NBg
RC and most types of Lithium batteries you MUST know your individual cell voltages charging and discharging.
Don't keep them were you cant afford smoke or fire!
Never above 4.2v never below 2.7v EVER!!!
HI power controller design. Game Changer
http://www.undergroundelectrics.ca/

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Re: Electric kart

Post by voltereta » Jun 24 2016 8:59pm

Taking many notes... Thanks for all the info!!!

Hillhater   100 GW

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Re: Electric kart

Post by Hillhater » Jun 24 2016 9:21pm

nuxland wrote:This is how the data are aquired during races. .......
....And for remote viewing there is web application using SignalR to display realtime information in a webbrowser. During the race I have a friend at home looking this and telling information via handsfree to me :)
.
Totally briliant !
Practically on par with some of the top F1 race teams....
....and better than most everything else on a race track !
Thanks for posting.
.... Did i miss the lap timer ?
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nuxland   100 W

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Re: Electric kart

Post by nuxland » Jun 25 2016 7:51am

Hillhater wrote:
nuxland wrote:This is how the data are aquired during races. .......
....And for remote viewing there is web application using SignalR to display realtime information in a webbrowser. During the race I have a friend at home looking this and telling information via handsfree to me :)
.
Totally briliant !
Practically on par with some of the top F1 race teams....
....and better than most everything else on a race track !
Thanks for posting.
.... Did i miss the lap timer ?
Every kart track has at least one place in the track that has magnets inside track (in Estonia there are only one in every track). We are using some knockoff laptime sensor and that is connected to olimex digital input. And using intrupts in olimex we get the signal when sensor goes over magnet in the track. Then olimex sends out canbus packet and bluetooth packet with time in ms between previous and this time it went over magnet. But we have a problem with that sensor, it gives us false signals and it is not working yet :(

PS! the data is sent over internet to server in 1s intervals, and it also recorded in server to human readable txt file, so if for some reason I broke the tablet, I still have some data :)

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Re: Electric kart

Post by Hillhater » Jun 25 2016 6:40pm

Ahh ! I understand... all sensors take a hammering on a kart with no suspension.
Lap time/count is normally the first data a kart driver has on board... ( after rpm for the ICEs)
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r3volved   100 kW

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Re: Electric kart

Post by r3volved » Jun 26 2016 12:13pm

That's so awesome!
Keep up the good work!!

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nuxland   100 W

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Re: Electric kart

Post by nuxland » Jun 27 2016 2:45am

It seems i hurt the motor at 9th lap in first race and it gave me DSP Encoder fault (Encoder input wire-off is detected)
Then after that I got over current and then again wire-off. And as winner completed 10th lap when I was standing I rolled with half the trottle to the finish line.

Next two races I could only go for 2 laps and then got the same error. Does someone know in depth about this error, because definitly there are no wires off :)
I think I hurt the hall sensors with that motor temperature. there are this motor configuration option in sevcon "openloop start FW%", maximum number i can write there is 9. what that FW% mean? And I think I need that zero 75-7 motor.

Controller watercooling helped very well it went to ~68 degrees and then settled there until encoder error :)

https://youtu.be/WNk1OJO8ErA
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nuxland   100 W

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Re: Electric kart

Post by nuxland » Aug 05 2016 4:57am

Loaned a ME1304 from a friend and installed watercooling to it. And yesterday got a chance to test it in private road.
Have a little to big rear sprocket with 36T and front 13T, so top speed is limited to around 100km/h because I do not want to go very high rpm.
I have limited rpm to 5400 in sevcon and also max motor amps to 550A in my first try. Ordered 30T rear sprocket to get a reasonable transmission.
1.jpg
2.jpg
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3.jpg
4.jpg
Video of the testdrive: https://youtu.be/UbV2-K4ht-s
Batterys were half empty, that's why so low voltages on load.

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nuxland   100 W

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Re: Electric kart

Post by nuxland » Aug 15 2016 8:23am

Concluded that ME1304 is not the right motor for electric kart :)
TempvsCurrent.jpg
TempvsCurrent.jpg (171.27 KiB) Viewed 634 times
You can get like only 3 minutes with 650A to the motor. And when motor inside temp reaches 100 degrees celcius then cooling water temp is still 20 degrees and starts to rise only after 5 minutes. It seems you can ride it continious with 350A-400A to the motor. It's 14-20kw then, depends of the rpm.
https://www.youtube.com/watch?v=G2uga3ToYZo

But 32.659kw is the max I have gotten from any motor on my kart. If battery temp would have been higher then voltage-sag would have been less and kw-s would have been higher :)

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Re: Electric kart

Post by Punx0r » Aug 15 2016 5:26pm

Have you considered perhaps a motor from a Zero motorcycle?

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Arlo1   100 GW

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Re: Electric kart

Post by Arlo1 » Aug 15 2016 8:46pm

I have Driven a shifter with a 75-7 Zero motor it rips hard!

Zero motor is a good way to go for sure!
My Leaf motor controller build. viewtopic.php?f=30&t=63982&p=963227#p963227
My YSR build http://www.youtube.com/watch?v=BRo8r5g4NBg
RC and most types of Lithium batteries you MUST know your individual cell voltages charging and discharging.
Don't keep them were you cant afford smoke or fire!
Never above 4.2v never below 2.7v EVER!!!
HI power controller design. Game Changer
http://www.undergroundelectrics.ca/

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Re: Electric kart

Post by Hillhater » Aug 15 2016 8:52pm

Have you managed to resolve the issue of what is the optimum "power" level for an electric kart ?
Too much power would require more battery power (and weight) which has a big negative effect on performance , particularly braking and cornering (both key factors for a kart)
You are also constrained by run time and recharge time if ever you are in a competitive event (not common)
I dont know what the optimum might be, but i doubt a 100kW kart is realistic, other than as a Youtube oddity or as a drag race novelty. Even 50-60kW would need a lot of battery for a typical 15 min "race" event
This is the same battery limitation the EMoto racers are battling against.
Waiting for the next step in battery cell performance.
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Re: Electric kart

Post by Hillhater » Aug 15 2016 8:56pm

Arlo1 wrote:I have Driven a shifter with a 75-7 Zero motor it rips hard! ...!
I assume You mean a "shifter" chassis ...but not with a gearbox ?
How much battery/run time did it have ?
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Arlo1   100 GW

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Re: Electric kart

Post by Arlo1 » Aug 15 2016 9:08pm

Hillhater wrote:
Arlo1 wrote:I have Driven a shifter with a 75-7 Zero motor it rips hard! ...!
I assume You mean a "shifter" chassis ...but not with a gearbox ?
How much battery/run time did it have ?
The setup I drove was with 2 zero bricks and a 75-7 and a size 4 I had no gears jus 1 speed it was geared for just under 80mph and would lay rubber at will in the low speed corners. Run time is decent I was not on a track but my friend Doug is racing it for fun against gas karts. Yes when I say shifter that's the chassis which has all wheel brakes and a big rear axle and set up for fast racing with the frame that will support the 54hp motor and 80lbs of batteries.
My Leaf motor controller build. viewtopic.php?f=30&t=63982&p=963227#p963227
My YSR build http://www.youtube.com/watch?v=BRo8r5g4NBg
RC and most types of Lithium batteries you MUST know your individual cell voltages charging and discharging.
Don't keep them were you cant afford smoke or fire!
Never above 4.2v never below 2.7v EVER!!!
HI power controller design. Game Changer
http://www.undergroundelectrics.ca/

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liveforphysics   100 GW

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Re: Electric kart

Post by liveforphysics » Aug 16 2016 1:09am

Hillhater wrote:Have you managed to resolve the issue of what is the optimum "power" level for an electric kart ?
I've also raced the Zero powered karts Arlo is talking about a few times. You can pass the 125cc and 250cc shifters at will on corner exits. By about 2/3rds down the longest straight they pulled evenly with the Zero drivetrain karts.

They lap the standard 8lap amateur events fine on the battery the stock FX comes with.
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nuxland   100 W

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Re: Electric kart

Post by nuxland » Aug 29 2016 1:47am

Was racing this sunday with retro karts again :)
Big thanks to Craig for selling me Zero 75-7 motor and Biff for helping me out with the config when I was stuck and all hope were lost :D

Had to configure sevcon "profile 1" to 4400rpm limit, because thats when field weakening starts. And with it the motor will heat up more quickly.
I also had 48% torque demand on that profile. But as I have a little button on wheel from what I could trigger "profile 2" where torque demand was 100% and rpm limit 6000 then it was fun using it 4 times in the race. But as you can see each using of it raised motor temp for 7 degrees instantly.

Here is video with data. I struggled with the motor conf in first 2 races, thats the reason I was easy on first two laps with the throttle in final race.
https://youtu.be/pbdnJMd8Reg

I have two extra temp sensors that are measuring motor external temp and controller extra heatsink temp. I have covered the motor sensor with foam tape so it does not gets cooled.
temps.jpg
Extra temp sensors
Does anybody know why Sevcon's motor temp is 10 degrees higher than controller one when both are not used and should be at ambient temperature?
I have it configured as KTY84 in combobox as it should.

Total weight of the kart including me on board was 234.8kg, so its should be little lighter that zero motorcycle?
weight.jpg
weight of the kart with me
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