Electric FunKart

[Moriss]

Hi guys.

Recently have started work on small eleectric gokart to have fun around with. The easiest way would be to buy a used one with gasoline engine, but I like idea about EV and to build my own one whould be nice challenge. About frame and mechanical element building I am confident. But the electric motor and batteries are totally new world to me.

After searching, watching and reading on web, I have made basic and low budget setup for power unit.

For motor I'm planning to use Kunray 72V DC 3000W 45A motor together with 50A controller. On paper it has around 5Nm wich should be enough.
https://www.aliexpress.com/item/32956364535.html?spm=a2g0o.store_home.productList_34702256.pic_7

Biggest challange are batteries. I want to make a Li-ion battery pack from 18650 cells.
72V 3kw is pretty big battery, so I'm thinkng of 3 batteries in series ( 3x 24V ). In my thoughts it would be more safe and reliable for everyday use and storage.

So the plan for battery is LiitoKala 25RM 2500mah 20A cells in 7S3P setup.
https://www.aliexpress.com/item/329...earchweb0_0,searchweb201602_,searchweb201603_
3,7V x 7 = 25,9 V and 60A. This should give around 1500 watts.
And for BMS I'm thinkong to get DYKB 7S 24V 60A BMS with cell balancer.

https://www.aliexpress.com/item/330...68#0#131923#18_668#808#4093#54_668#888#3325#4

So at the end I would have 3 identical batteries total of 77,7 Volts and 4600 Watts. I have doubts about what happens to each individual battery BMS when all 3 batteries will be connected in series.

This is my big plan

Am I on the right way or my cauculations are totally wrong here?
Would be grateful for any advice.

 

[Hillhater]

Tip ....
Building your own kart frame is a pointless, time consuming, exercise when used rolling frames are readily available for <$100.
Buying your own materials, axles, wheels,bearings, seat, etc etc all adds up fast,..and the results are usually disappointing unless you are a pro frame maker.

 

[enrengineering]

I built 3 go karts from scratch and one tip: simplicity will be your friend.
This is the last one I built, maybe you can pick some ideas from it: https://www.youtube.com/watch?v=QXtdjzxoCJQ&t=64s
If it's the first time you are building one, I recommend to you to start from a salvage frame or a rolling chassis, that way you will only need to fabricate the motor/battery/controller mounts.
Good luck with the project!