Build

Hello,
My goal is to build a stand up scooter.

I wish i could build a custom scooter chassis, but I dont have the equipment.

I found a frame on alibaba that I plan on purchasing and using.

The frame looks nice, and has enough space to fit the battery I want to put in.

The main goal of this project is to get some practice building a battery, I have developed a keen intrerest in the ebike scene for the last year

I've given this some thought, and want to get the main components first then worry about the smaller things.


Here is a list of the components i plan on using, please feel free to recommend stuff, as I've been putting this together in my downtime and I want to chose the most efficient products.

Scooter Build List
Frame: https://www.alibaba.com/product-det...ml?spm=a2700.shop_plgr.41413.9.69be5d7cpucoi1 This has a 150mm wheel dropout. I hope it is truly forged aluminum
Motors:https://www.uumotor.com/11-inch-detachable-3000w-3500w-electric-scooter-motor.html Specifically the 60V 3000W 145mm dropout size with a 210mm shaft, I was planning on putting small bushings to fill the gap.
Motor Controllers:https://www.uumotor.com/programable-60v-50a-sine-wave-brushless-motor-controller.html This controller is the only 50A continuous controller I could find available to buy.
Cells:https://www.18650batterystore.com/products/samsung-40t?variant=37119892816023 I Already have 50 of these cells, my plan was to buy more to make a 60V, 16s5p pack.
BMS:https://www.aliexpress.com/item/400...1;69.61;-1;-1@salePrice;USD;search-mainSearch This is where I get confused, this BMS is rated to discharge at 100a, I know that having a BMS for these cells is important for charging and balancing, but if i add a physical switch to bypass the BMS for discharge, can I get away with using this BMS? Im just nervous ill trip an overload switch or something of the sort.
Throttle/Display:This is still TBD, I know that there is no industry standard for this, so I dont know how I would go about finding a compatible display to go with the controller.


These are all the parts for now, Please let me know what else I need to get the thing running.

I know that this build is very dumb, and an ebike would be much better with these specs, but I want to build it for the practice and frankly because I love riding around on the scooter.


The motors and controllers are shipped by the same company, UUmotor. I'm not sure about their products but they look real and from what I see, these are perfect for my application,

I have to buy another 50 cells to make my pack, but I will be able to fit the cells within the chassis that I sent.

Please let me know if everything is compatible, and some suggestions for a throttle if anyone has had experience with that brand of controller.

Thank you for reading this,

First off, it's cool that you're going to build your scooter. Good luck.

Regarding the parts:
1. You wrote "motors", plural. I don't think you should use more than one 3kW motor on something as lightweight as a stand-up scooter. Even just a single 3kW seems like a massive overkill. I ride a 200kg motorcycle with a single 6kW motor. How hard do you plan to push this thing?
2. That controller is new to me, but I've only recently started playing with controllers. From what little I learned so far, don't get a motor that isn't common around the community/forum. These are advanced components and programming/configuring them is not a trivial task.
3. The cells. You're using Lithium Cobalt cells (judging from the 4.2V max voltage), so make sure you buy a Li-On BMS. Personally, I don't like the volatility of LiCO cell. Abuse them enough and you get a self-oxidizing fire and shit hits the fan. LiFePO4 or LTO is just so much safer for EVs (for the cost of lower energy density and specific energy). You already have a bunch of these cells, so it's probably not an options for you to switch chemistry, but if it is - I'd go with an 18s LiFePO4 pack.
4. The BMS. First off, make sure to pair the BMS with your chemistry. Don't order a LiFePO4 BMS if you're going to use Cobalt cells. Regarding bypassing your BMS, I highly advise against it, especially for LiCO. Your BMS software will probably be OK with it, but you'll lose a lot of the protection it offers and some of the functionality. No over/under current, voltage and temp protection at 80km/h seems scary. If you take your motor down a kW or two, your BMS will cost a whole lot less (same goes for most other componenets)
5. When you use a common controller like a Sabvoton, Kelly, Sevcon, Fardriver, Votol or any of the other that are common here, you'll have quick access to compatible throttles and displays. I just got a Fardriver and am testing it out. Good stuff so far. Had a bad experience with Votol and Sevcon.

I guess you are going with a dual motor setup. If so, I would go with a more powerfull controller. This small motors can easily handle 100A peak during short and fast accelerations. Using the 40T in 5S will give you 225A discharge capability - if you are not going to use such power, it make more sense to have a more energy dense (and cheaper) cell for better range.