Electric kart

Electric cars, trucks, ATVs, NEVs - things bigger than a motorcycle.
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LuigiDesing   10 µW

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Re: Electric kart

Post by LuigiDesing » Apr 03 2017 5:07am

nuxland wrote:
LuigiDesing wrote:Hi nuxland,
How long does you take to charge the batteries?
I'm using 3kw elcon charger and it takes about 50 minutes. Depends how much I use up the battery.
Actally charger is charging at 24A and usually i'm using 21Ah in a race, so yeah 52 minutes.
I added also extra charging port to the battery when redoing it, so now I can charge with two 3kw chargers if needed.
Racing with full power usable (improved cooling) will be more KWh drained I guess, so looks much better to charge in half hour with dual 3Kw charging ports, ;)

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nuxland   100 W

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Re: Electric kart

Post by nuxland » Apr 10 2017 12:53am

Was testing my improved battery pack in the road. 0,1V was difference between highest and lowest cell under 600A load :)
https://www.youtube.com/watch?v=fKnjkyAne7U

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Re: Electric kart

Post by Doctorbass » Apr 11 2017 11:36am

nuxland wrote:Was testing my improved battery pack in the road. 0,1V was difference between highest and lowest cell under 600A load :)
https://www.youtube.com/watch?v=fKnjkyAne7U

That is very good!.. cells seem to have a very nice RI match!

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nuxland   100 W

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Re: Electric kart

Post by nuxland » Apr 20 2017 1:29pm

Went to a hub dyno today, but could not measure because my kart drivetrain is so light (no flywheel or anything that sustain some momentum).
We could get to dyno target rpm but when then giving more throttle it got very junky/bumpy and he let the throttle back, because wanted not to break it.
Dyno.jpg
Will try next week again with drum dyno and hope it works there because drum dyno has flywheel built in and should have enough rolling mass :)

catacon   10 µW

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Re: Electric kart

Post by catacon » Apr 24 2017 11:42am

Nice! I'm very interested to see what that dyno looks like.

falshami   100 W

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Re: Electric kart

Post by falshami » Apr 25 2017 6:37pm

so after reviewing your posts here, how did the 48v motor perform with 96v? im guessing it didnt totally explode? i am thinking about using the hpc700 controller which is a 96v controller with a a 20kw potential output, i was going to limit it to 5500 rpm however and limit the voltage output on the controller to around, 72v and maybe slowly rev it up assuming that the water cooling can keep up and keep it cool. im also not hoping to push her all that hard mainly drive around town. but can the 48v 10kw motor handle the 96v?

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nuxland   100 W

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Re: Electric kart

Post by nuxland » Apr 28 2017 3:03pm

Sevcon controller is smarter that that VEC500, so I configured my sevcon to output maximum of 66V to the motor. But as sevcons input voltage (battery voltage) was 96V then it could feed more phase current to higher rpm. Here was my configuration when I was using sevcon and GM motor.
GM.png
GM.png (21.21 KiB) Viewed 2693 times
Here is one acceleration from 3000rpm to 5700rpm where sevcon could still feed over 300A to the motor at 5500rpm.
GM_Data.png
GM_Data.png (49.36 KiB) Viewed 1608 times
I weighted my current battery with 20g precision and it is 49,360kg
Battery.jpg
Battery.jpg (226.17 KiB) Viewed 1608 times
Will go to dyno next week, because it was raining all week and dyno is outsite :(

falshami   100 W

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Re: Electric kart

Post by falshami » Apr 28 2017 3:07pm

What sevocn controller did you use? it seems like this unit might be perfect for me, id love to limit my motor to a max of say 72v since that would give me plenty of RPM and power with the new combination. plus with water cooling my motor should stay nice and super cool!

your setup is insane!!

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nuxland   100 W

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Re: Electric kart

Post by nuxland » Apr 28 2017 3:24pm

falshami wrote:What sevocn controller did you use? it seems like this unit might be perfect for me, id love to limit my motor to a max of say 72v since that would give me plenty of RPM and power with the new combination. plus with water cooling my motor should stay nice and super cool!
your setup is insane!!
Gen4 Size6 but the software with canbusadapter will cost you almost the same as the controller :(
GM watercooling is crap, so is other this type of motor watercooling. You can look one of my posts where I tested friends ME motor. Water temp starts to rise to slowly, like motor inner temp was 100c and I had tested like 3 minutes and then pulled to a stop (water was still 26C) and after 2 more minutes I could see that water temp was rised to 35C. Another friend has the same ME motor in his e-kart and he could do like 3 laps and then controller had lowered current because motor temp was over 100C.

Watercooling is enough when you do not go over 300A continous phase current and some very short burst to 600A. But for kart racing this is not enough.

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nuxland   100 W

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Re: Electric kart

Post by nuxland » May 12 2017 3:02pm

Finally got to the dyno :)
https://youtu.be/SMk7YdEvCYs
Dyno.jpg
Dyno result
At 3600rpm got at the wheels 55,85kw and motor pulled from the battery fraction below 60kw.
So around 4kw went to the heat, some of it in controller and other in motor thats around 93% efficency.
BatteryPower.jpg
BatteryPower.jpg (80.99 KiB) Viewed 751 times
But at 5500rpm around 9kw went to the heat already
FieldWeakening.jpg
FieldWeakening.jpg (81.62 KiB) Viewed 1607 times
PS! Do not look cycle analyst battery amps, because it is still using 300A rated shunt and it does not show numbers over 600A :(

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Arlo1   100 GW

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Re: Electric kart

Post by Arlo1 » May 12 2017 6:43pm

Great work is this dual controllers?
My Leaf motor controller build. http://endless-sphere.com/forums/viewto ... 27#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!!!
Support me on Patreon. https://www.patreon.com/user/posts?u=6842045
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nuxland   100 W

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Re: Electric kart

Post by nuxland » May 12 2017 11:54pm

Arlo1 wrote:Great work is this dual controllers?
No, this is with single size 6 with maximum it could do. Temp rised from 38C to 80C in this final pull.
I did togehter 3 pulls in a row, first with 70% torque, then with 100% but controller got unknow error then and then this final that went error free.
Temperatures.jpg
Temperatures.jpg (92.78 KiB) Viewed 1607 times
This dyno has very big mass, it had two rolls 81cm in diameter and if I remember correctly then it's inertia was 161 kg/m3 (I can be mistaken by unit)
So it took 20 seconds to go from 1000rpm to 6000rpm, that I do normally when driving well under 3 seconds.

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Arlo1   100 GW

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Re: Electric kart

Post by Arlo1 » May 13 2017 12:03am

nuxland wrote:
Arlo1 wrote:Great work is this dual controllers?
No, this is with single size 6 with maximum it could do. Temp rised from 38C to 80C in this final pull.
I did togehter 3 pulls in a row, first with 70% torque, then with 100% but controller got unknow error then and then this final that went error free.
Temperatures.jpg
This dyno has very big mass, it had two rolls 81cm in diameter and if I remember correctly then it's inertia was 161 kg/m3 (I can be mistaken by unit)
So it took 20 seconds to go from 1000rpm to 6000rpm, that I do normally when driving well under 3 seconds.

Does the Dyno have SAE corrections turned on?

Or any Corrections it will cause it to read high. I think you are at the VERY LIMIT/Record of a single size 6.
My Leaf motor controller build. http://endless-sphere.com/forums/viewto ... 27#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!!!
Support me on Patreon. https://www.patreon.com/user/posts?u=6842045
http://www.undergroundelectrics.ca/

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Doctorbass   100 GW

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Re: Electric kart

Post by Doctorbass » May 13 2017 1:04am

Arlo1 wrote:
nuxland wrote:
Arlo1 wrote:Great work is this dual controllers?
No, this is with single size 6 with maximum it could do. Temp rised from 38C to 80C in this final pull.
I did togehter 3 pulls in a row, first with 70% torque, then with 100% but controller got unknow error then and then this final that went error free.
Temperatures.jpg
This dyno has very big mass, it had two rolls 81cm in diameter and if I remember correctly then it's inertia was 161 kg/m3 (I can be mistaken by unit)
So it took 20 seconds to go from 1000rpm to 6000rpm, that I do normally when driving well under 3 seconds.

Does the Dyno have SAE corrections turned on?

Or any Corrections it will cause it to read high. I think you are at the VERY LIMIT/Record of a single size 6.

Nuxland had only reported 4kW( batt input power vs power at the wheel) loss at full power witch make me think that is or very impressive or indicating there is an error with the SAE correction

Doc
CURRENT PROJECT: 2WD duo MXUS/Max-E ebike 32kW
http://endless-sphere.com/forums/viewto ... =3&t=65764
-Fastest speed record 117 km/h on flat
-Fastest 1/4 mile@ 114km/h on flat and 16.316 sec
-Succeded to haul a 19200 pounds schoolbus!
113kmh Gianthttp://www.evalbum.com/3406
Mongoosehttp://www.evalbum.com/1947
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Arlo1   100 GW

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Re: Electric kart

Post by Arlo1 » May 13 2017 1:09am

Doctorbass wrote:

Nuxland had only reported 4kW( batt input power vs power at the wheel) loss at full power witch make me think that is or very impressive or indicating there is an error with the SAE correction

Doc
Its not an ERROR.

The SAE corrections on dynos are there for ICE engines to try to make all readings consistent but in many cases it adds a bit of power to the curve to compensate for things like ambient temperature or atmospheric pressure.
My Leaf motor controller build. http://endless-sphere.com/forums/viewto ... 27#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!!!
Support me on Patreon. https://www.patreon.com/user/posts?u=6842045
http://www.undergroundelectrics.ca/

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nuxland   100 W

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Re: Electric kart

Post by nuxland » May 13 2017 2:55am

Arlo1 wrote:
Doctorbass wrote:

Nuxland had only reported 4kW( batt input power vs power at the wheel) loss at full power witch make me think that is or very impressive or indicating there is an error with the SAE correction

Doc
Its not an ERROR.

The SAE corrections on dynos are there for ICE engines to try to make all readings consistent but in many cases it adds a bit of power to the curve to compensate for things like ambient temperature or atmospheric pressure.
The guy there told me that in reqular cars you have to multiply result by 1,2 and then devide to 1,36 to get kw. So I think the numbers are without ICE engine SAE corrections.
But as this dyno required me to go 1000rpm and then he pressed start (he had configured the start to 1000rpm from motor and dyno then calculated ratio) and then I hit full throttle then it seems we have shifted the rpm a little bit. He had max motor 5600rpm in the graph but actually it was 6000rpm in the motor. So this can give some kind of error, but I will ask him over that and he will send me txt export from the dyno also, then I can compare some number in excel graph :)
And mybe I will go one more time and then we will start from 0rpm. We tried once but wheels were spinning from 0rpm when I hit full throttle 8)
But then it was not strapped with this extra strap that gave extra tension between wheels and drum.
Dyno1.jpg
Dyno1.jpg (243.9 KiB) Viewed 1608 times
dyno2.jpg

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nuxland   100 W

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Re: Electric kart

Post by nuxland » May 17 2017 2:58pm

Tested two times 10 laps today. Both times motor temp went to little bit over 100C and max rpm were limited to 5000 both times, thats 115 km/h. First time was with 60% torque and second time with 75% torque. Target was to get the correct torque % so motor will last 10 laps. But it seems also battery temps ware getting high. After first time battery temps rised to 45C. And when we were charging for 1h they dropped to only 38C. And after second time they were 54C and that seems to hot (I have temp sensors measuring cell tabs and I can imagine that cell temp inside was higher maybe.
First run
60Torque.jpg
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Second run
75Torque.jpg
75Torque.jpg (91.94 KiB) Viewed 1607 times
So it seems that motor heated up more at 75% Torque that was to be expected :)
But it seems that I used same energy from the Battery with 75% Torque, even we drove 1 lap extra.
It seems kart reached target speed quicker and thats the reason it used the less energy for the same distance.
60Speed.jpg
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75Speed.jpg
75Speed.jpg (114.54 KiB) Viewed 1607 times
Average it's 2Ah per lap, a little bit less actually.
Here is second run video also (Analogger GPS were having glitches and could not use that for laptimes)
https://youtu.be/LKFe9fC_ldE

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Re: Electric kart

Post by ugot1 » May 21 2017 2:12am

hi everyone !
i am pretty new to electric carts but we are a group of good and young workers and we have a kart that we want to convert.
can you suggest me a motor, batteries and controller that we can start of with ?
thanks in advance

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nuxland   100 W

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Re: Electric kart

Post by nuxland » May 21 2017 1:38pm

Went to race with "hobby race event", where they race with regular Rotax Max and DD2 versions of racing karts.
Event was with 15 laps (thats 5 laps to many for my reqular driving) but I tried it anyway.
First race everything was cold enough so at the end of the race everything was in ok temperatures.
I had on some old rear tires and sadly they did not gave me enough grip in the corners :(
As I drove out to the grass, then motor got time to cool down a little bit, but at the end was over 100C.
Rapla1.jpg
Rapla1.jpg (130.97 KiB) Viewed 1607 times
And here is also video for race 1 https://youtu.be/_OjEdIBejoE

I knew that I can not parcipate in every race (they had 5 races and with 50 to 60 minutes apart) so I was aiming first and third and fifth.
But as I recharged my battery and changing rear tires to also used but in my opinion better tires the battery did not want to cool down at all.
And as I finished first race with 38 to 45 degrees battery temps, I started my second race with 33 to 41 degrees temps. So my bottleneck is indeed battery and not motor.
It seems that one of the temp sensors is not touching cell interconnect but the plexi glass behing it.
For the next event I was thinking to bring along cooling case with ice in it (the one thats ment to be to cool beers) and then I unmount battery and stick it into that case for charging. This should bring enviroment around battery to 0 degrees and its then 22 degrees lower that it was in the air that day :)
And i only drove 10 laps out of 15 in this race, because I saw that my motor temp was almoust 110C and I was tired also, so no point to brake the motor.
You can see also from the lap times that 6 laps I could do it and then my arms started to hurt and I lost 1s with a lap :)
Rapla2.jpg
Rapla2.jpg (128.62 KiB) Viewed 1607 times
And video for race 3 https://youtu.be/fD9kfT3C6oQ

As battery temps rised over 50 degrees and I knew that they will not come down with 2 hours that I had between next race I did not raced thir fifth race.
A123 20Ah pouches are working good up to 55 degrees and I know that already over 50 in my temp measurement they do not perform very well anymore.
Both times I have restricted the controller for 60% of maximum torque and motor RPM were limited to 5000, because over that I'm not gaining anything in the track.

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Re: Electric kart

Post by Hillhater » May 21 2017 5:16pm

The F1 teams use dry ice (CO2) to cool hot parts (brakes , radiators, , electronics etc) , in the pits.
A small box of dry ice pellets attached to a cordless blower (or a custom made shroud if you can) to blow super chilled air over the hot parts.
The FE cars run a 30kW pouch pack fully imersed in a liquid cooling enclosure in the cars. And they are using top spec cells at only 8-9 C max discharge. And recharging is off the car !.
This forum owes its existence to Justin of ebikes.ca

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Re: Electric kart

Post by amberwolf » May 21 2017 7:22pm

ugot1 wrote:i am pretty new to electric carts but we are a group of good and young workers and we have a kart that we want to convert.
can you suggest me a motor, batteries and controller that we can start of with ?
I would suggest using what is in use on the kart in this thread, as it is already proven to work.

If that's not an option, perhaps use what's on one of the other karts in the other threads. The search below pulls up a number of them; not every thread listed is relevant:
https://endless-sphere.com/forums/searc ... mit=Search

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Re: Electric kart

Post by Dauntless » May 21 2017 9:22pm

https://endless-sphere.com/forums/viewt ... 14&t=55074

Don't know if this has been linked here or not.
Any sufficiently advanced technology is INDISTINGUISHABLE FROM MAGIC!
- Arthur C. Clarke

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nuxland   100 W

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Re: Electric kart

Post by nuxland » Jun 19 2017 8:05am

I need to dig into my harness and figure out what was the reason for "DSP error encoder wire out detected" when raced last saturday.
First race of the day video: https://youtu.be/UKnm5dCwV4Y
I charged my battery pack in my car trunk and had a/c turned to minimum. It was 24C outside and I needed to cool some heat down from the pack when charging.
I must say that I got maybe only 5C degrees off this way, but it was better that charging outsite in the sun.
Charging1.jpg
Charging1.jpg (233.91 KiB) Viewed 1604 times
charging2.jpg
25AhPack.jpg
I need to install forced cooling to my small pack, because just driving average 70km/h does not cool them at all as I had hoped.

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Re: Electric kart

Post by fechter » Jun 19 2017 8:30am

Wow! that thing really hauls. Nice work. I love your instrumentation display. Looks like the batteries are sagging quite a bit, but that's a lot of amps.
"One test is worth a thousand opinions"

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Re: Electric kart

Post by Doctorbass » Jun 19 2017 10:04am

nuxland wrote:I need to dig into my harness and figure out what was the reason for "DSP error encoder wire out detected" when raced last saturday.
Some dsp error are due to the throttle voltage range that is wrong.. in that case you need readjusting the throttle voltage limit.

But for encoder error, that might be due to the proximity of itself relative to the magnet on the shaft. The adjstment range is very narrow. There is some spacers that you can add or remove between the encoder pcb and the motor location where it is installed. this will shift the voltage range of the encoder. You can see the results in the motor comissionning option after you rotate the shaft manually few turn.. it record the voltage range detected by the hall of the encoder. I dont remember the range but tonight when i'll be back home i'll check in my notes.

Doc
Last edited by Doctorbass on Jun 20 2017 8:51am, edited 1 time in total.
CURRENT PROJECT: 2WD duo MXUS/Max-E ebike 32kW
http://endless-sphere.com/forums/viewto ... =3&t=65764
-Fastest speed record 117 km/h on flat
-Fastest 1/4 mile@ 114km/h on flat and 16.316 sec
-Succeded to haul a 19200 pounds schoolbus!
113kmh Gianthttp://www.evalbum.com/3406
Mongoosehttp://www.evalbum.com/1947
YOUTUBE---https://m.youtube.com/user/Doctorbasss
http://twitter.com/DocbassMelancon
I speak FRENCH and english

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