Electric Exprit (OTK) Kart

I decided on kind of a whim I wanted to try my hand at building an EV kart that has a shot at being a legitimate race class. With that in mind I worked on designing/building an EV package that would drop into a standard kart chassis with no chassis modification. Here’s my breakdown

Goals:
Ka100 speed
15mins of track time at race speeds
battery in place of fuel tank
no heavier than Ka100 package

Powertrain:
Battery: 72V (20s8p) Molicel P42A
Motor: QS139 90H
Controller: Votol 200sp

Weights:
Battery: 28lbs
Controller with mount: 9lbs
Motor with mount: 32lbs


I've been able to test it out on track and it performed great, giving me a solid 15 minutes of racing condition track time on a charge.

Version 2 is in the works as I'm trying to build more of a field of them at the at the local track as well as gaining confidence in my battery building abilities allowing me to get more creative in the pack design.

Thanks for looking

Awesome! very similar to my build. I also finished and was able to test it. my battery is a little under powered for the current I am needing so i am getting a new pack. 24s13p with molicel p42a cells. I hope they perform well. How much current are you using? how did you secure the pack? Are you missing a Bearing carrier on your axle?

Very nice package.. Probably the best Ekart packaging i have seen.
Questions..
Is the pack “swapable” Easily .?
The motor, battery, controller , at 90 lb , is significantly heavier than a KA set up (35-40 lb ?) ..how competitive is it with KA ?
Note:: i realise it is intended to be a separate class, but thinking lap times.

Wimbi39 said:

Awesome! very similar to my build. I also finished and was able to test it. my battery is a little under powered for the current I am needing so i am getting a new pack. 24s13p with molicel p42a cells. I hope they perform well. How much current are you using? how did you secure the pack? Are you missing a Bearing carrier on your axle?

Click to expand...

I am running 72V with a current limit of 120 amp. The battery is secured to the uprights with a nylon strap and buckle, i had it off for glamour pics, no issue with movement and i'll get a pic next time i'm at the track. the OTK STV-4 chassis runs without that bearing carrier since the chassis is geared towards lower HP classes.

Hillhater said:

Very nice package.. Probably the best Ekart packaging i have seen.
Questions..
Is the pack “swapable” Easily .?
The motor, battery, controller , at 90 lb , is significantly heavier than a KA set up (35-40 lb ?) ..how competitive is it with KA ?
Note:: i realise it is intended to be a separate class, but thinking lap times.

Click to expand...

The pack is very swapable, undo the strap (not seen for glamour pics) and it pulls right out without needing to take anything else out.
It's hard for me to say 100% how competitive it will be with the KA my goal is as fast and it obviously has way more low end torque but once the track officially opens I plan on having the WPK (Will Power Kart) coach in one of his KA's and this back to back trying to tune in the speed to make it equivalent.

KA is a bit heftier, 40 for the motor then you need to include the mount/exhaust/starter battery/harness (15lb ish) then a tank full of fuel (10ish). Obviously the battery setup is still more, but about as close as i could hope.

With me weighing 195 the kart scaled at 375lbs which i'm very happy with, I've also learned areas where I can likely shave ~5lbs off the build, by making a better controller mount and downsizing my massive wiring i got going on.

Here is the start of battery pack V2. The OTK chassis has a very generous fuel tank area with the uprights being vertical, I am working to make the 2nd pack more universal similar to a KG fuel tank. I plan on building 2 more complete packages to give to the local teams at my home track so we can start an EV class this year.

I saw a dyno of that motor on a go kart reach 45hp+ to the ground. It was crazy.

Good Work karting_desire. My project is very similar to your project. My initial questions is relation battery dimensions and weight. Other question is refers to what battery provider? What cost and necessary components? Thank you!