First time building an electric /EV scooter

[mazzak]

Hi, I'm Maz, and I'm looking to start building an e-scooter.
People from Reddit sugggested I post in here about my build, I need knowledge, tips and tricks, thanks in advance.

I want to use this off-road often, and at least 20km range would be great.
I'm thinking of possibly leaving the 16" front wheel that came with it, leave at the back for now perhaps and put the 20" hub motor wheel at the front?
I'd prefer have the power at the back wheel for maximum fun though.

ALSO - I realize I went ahead and bought some stuff that I will have to replace sooner than later - aka the frame.
I'm buying the rest of this stuff based on that I'll make a version 2 of this scooter, it's an interesting learning experience!

I'm building a 20" * 4" fat wheel scooter, I'm in Aus, and so far getting most parts from AliExpress.
Here is the scooter I bought for the frame, the only decent option in Aus that I found cheaply!


I found inspiration when I found thiis images;
View attachment 3

The scooter, it came with a 16" front, and 12" rear wheels.
Here's the 16" wheel put on the back, and a 20" mockup front.
unable to upload that image but you know what I mean,
I'm going to replace both front and back with 20" wheels.

I want to install a 20" rear 3kw hub motor on the scooter, the front fork will be cut off, as I've ordered a 20" MTB oil suspension front fork.
I definitely also need new handlebars! recommendations?

What brand front disc break do you recommend? I'd need a caliper as well.
I'm going to install a folding seat with suspension on it too.

I'm interested in using this or similar seat suspension.
https://aliexpress.com/item/32508118142.html?spm=a2g0o.productlist.0.0.71cb6327QY5lVl&algo_pvid=1cdaeb77-4551-46df-9ce5-f2bc966193d7&algo_expid=1cdaeb77-4551-46df-9ce5-f2bc966193d7-27&btsid=0be3743b15921570030522692e938d&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_

This is the motor I've ordered.
https://aliexpress.com/item/4000288190575.html?spm=a2g0s.9042311.0.0.2d5f4c4dKR1Ejx

and the controller
https://aliexpress.com/item/32869786514.html?spm=a2g0o.cart.0.0.660c3c0015Pt43&mp=1


BATTERY?
The battery am still undiceded on.. 48V or 72V..

I'm following this guy on YT with how he did his bike.
https://www.youtube.com/channel/UC9QK0Y_yFdIfYTdKp6FEMVg

 

[Dauntless]

You know, some people laugh at this at first, but I think of it as the way the mouse eats cheese. At first. I like the idea of MORE brakes than you really need, rather than less the way so many build their bikes.

Unfortunately I don't really have a set to show you, but you can piece it together.

https://www.aliexpress.com/item/32789057786.html

https://www.aliexpress.com/item/32908838620.html

https://www.aliexpress.com/item/33032406585.html

 

[mazzak]

I am refunding and changing to buy this cotroller instead. Sabvoton SVMC96120 controller https://www.aliexpress.com/item/33061907860.html?spm=a2g0o.cart.0.0.4a473c00uLnwyZ&mp=1

I'm ordering this suspension seatpost;
https://www.aliexpress.com/item/32299135167.html?spm=a2g0o.cart.0.0.4a473c00uLnwyZ&mp=1


This Stainless Steel handlebar end mirror
https://www.aliexpress.com/item/400...earchweb0_0,searchweb201602_,searchweb201603_


These Carbon fibre handlebar & Stem;
https://www.aliexpress.com/item/32727805872.html?spm=a2g0o.cart.0.0.5bd13c00tfWJat&mp=1


This throttle/power button(s);
https://www.aliexpress.com/item/4000910455581.html?spm=a2g0o.cart.0.0.5bd13c00tfWJat&mp=1



Still undecided on battery+BMS...

Perhaps 3x 24V LiPo?

I'm going to do the exact same setup on my mountain bike as well :wink:

 

[Balmorhea]

Don't put a powerful front hub motor in a suspension fork. It prevents the suspension from working, and it will break the fork tips.

The riding position and weight distribution of that kind of scooter limit the amounts of motor torque and braking force you can bring to bear. With small wheels and high center of mass, any decent quality disc brake will be borderline excessive in terms of instantaneous braking force, but at the same time could be marginal for dissipating the energy of slowing from >40 mph speeds. You could easily wind up with a brake that is overly touchy to apply, but also subject to overheating.

Tektro makes some extra-thick 2.3mm rotors which would make sense for your application, and also levers designed for twin calipers (which would reduce the lever’s mechanical advantage when used with a single caliper).

It would be a very good idea to stretch the wheelbase quite a bit longer than the scooter in the picture, so that you can use more motor torque and more braking power without tipping your scooter over. That would also tend to stabilize the handling.

I don’t think building a 3000W stand-up scooter on your first go is a good idea at all. It’s much cheaper and more forgiving, and results in a lighter and more fun scooter, to use a 750-1000W kit as a starting point (and make your noob mistakes with that). 4”+ fat tires add weight, bulk, and expense, but they slow you down, impair handling, and don’t give you any real benefits on the street versus say 2.5” tires.

if you already own the scooter in the picture, my suggestion is to convert it as it is, with the most powerful kit you can find with a 16” front wheel. Put better brake pads (e.g. Kool Stop salmon) on the brakes you have. It looks like the fork might have narrow spacing. If it’s much less than 100mm, you will have to bend the fork wider (difficult) or find a narrow front hub motor for a folding bike. Or you could get a 12” motor wheel for the rear, and juice it with a few extra volts and amps to put it in the 750 watts and up class. Shoot for say 25mph, because that’s slightly too fast for this kind of scooter, but not categorically stupid.

Then you can take what you’ve learned and apply it to a multi-hp stand-up scooter, if you still want one.

 

[mazzak]

Sorry I should have made it more clear as to what my plans are.

Yes I own this scooter, I am using it as a base, I'm going to cut it up, and make it wider, and a longer wheel base.

The 20" hub motor will be put on the back,
I ordered the 20" fatbike front suspension fork so I can fit 4" fat tires if I want to.
I'll be using a stock 20" BMX front wheel for now, I'm going to order a better front wheel later, the BMX wheel is temporary.
I'm only going to use upto a 2.5 - 3" wide tire at the front at max, I thought a 4" front fork just gives me plenty of room to work with :wink:
It's going to be 20" front and back.

I'll make the rear as wide as I need when I cut it off to lengthen it, I'll angle it so the base is level front to back.

I'll put a 2.5" or so tire on the rear hub motor rim, with goo and a rubber liner to prevent flats.

What length and width would you guys recommend, without making it too long? I'm going to do some drawings on paper while I figure out the dimensions, before I cut it up.

I'm planning to put the batteries in the floor of the scooter, I have aluminium diamondplate that I'll use for the floor and the battery box.

I want to build this right, the first time. Well... as well as I can.

I will look at the Tektro breaks, sounds like they'd be perfect. I know what you mean about being too touchy etc, I definitely don't want that. Also, sounds like that lever would be great. it's still hydraulic right?


So with the Tektro Dorado brake system, I'd need;
Tektro HD-E730 (Is this designed for dual calipers so it has better mechanical advantage? or which one specifically should I get?, or rather, what exact parts would you recommend? I'm guessing these Rotor and Brake pads here would be okay for it? if not, which ones? Thanks in advance).
Tektro TR180-17 / TR203-17 rotor
Tektro Q11TS brake pads

Where can I buy this kit? I am in SA, Australia.
I might have to buy it from the US, through a shipping forwarding service I'm guessing? Or Europe?

I found it on Alibaba, but I'd need to contact the supplier to get the parts..

Whats the easiest way to buy this brake kit?

I'm going with good quality parts, so that I can just throw this kit onto a bike frame later on, if/when I want to / or make my V2 E-Scooter frame :wink:

Thankyou for all the excellent info!

 

[mazzak]

Re; The hydraulic e-bike brakes.

I have found some in Australia designed for e-bikes, do they look okay to use?
From what I've read, as long as it's 2.3mm e-bike hydraulic 4pot brake system, any of them will be ok.
Like this one I found, yeah?
Magura MT5e HIGO-Opener MTB Disc Brake
https://www.wiggle.com.au/magura-mt5e-higo-opener-mtb-disc-brake

after more searching, I found an accurate picture of what I'm modelling my scooter after;




Also, as for the battery!
I'm planning to buy new cordless tool battery packs, which have 2188mAh 18650 cells in them.
It turns out to $3.90AUD per cell

I want to use 18650's as I have all the gear for working with them.
I want to build a • 52v - 14s,2p 18650 pack, then upgrade it with more parallel packs when I can afford to.

So that's what, 2188mAh * 2P = 4,376mAh/4.3Ah 52V pack,
So a 14s3p would be 8,750mAh/8.7Ah, at 52V

I hope I've got that right. So how many amps can I pull from these 2 scenarios? I'm not sure on calculating it it's 5am and I haven't slept in days.. -_-

what is the realistic capacity/ distance I can achieve with this motor I chose, on say, medium power level selected on the throttle switch?
Cheers, Maz.

 

[Dui ni shuo de dui]

I hope I've got that right. So how many amps can I pull from these 2 scenarios?

You didn't provide enough information to answer this question.
We need either the C rating of the cells, or the individual maximum discharge current of each cell.

what is the realistic capacity/ distance I can achieve with this motor I chose, on say, medium power level selected on the throttle switch?

That's impossible to definitely answer because it largely depends on riding style.
I would expect something like 10kilometers with those 8.7Ah, but that's a wild guess.

 

[DaLanMan]

Also, as for the battery!
I'm planning to buy new cordless tool battery packs, which have 2188mAh 18650 cells in them.
It turns out to $3.90AUD per cell

I want to use 18650's as I have all the gear for working with them.
I want to build a • 52v - 14s,2p 18650 pack, then upgrade it with more parallel packs when I can afford to.

So that's what, 2188mAh * 2P = 4,376mAh/4.3Ah 52V pack,
So a 14s3p would be 8,750mAh/8.7Ah, at 52V

I hope I've got that right. So how many amps can I pull from these 2 scenarios? I'm not sure on calculating it it's 5am and I haven't slept in days.. -_-

what is the realistic capacity/ distance I can achieve with this motor I chose, on say, medium power level selected on the throttle switch?
Cheers, Maz.

Ok, I am not following your path here brother.

You want to buy battery packs that are pre-assembled for a power tool...

then... take them apart to get at the cels to then put into a new package?

Or are you talking about gang plugging in these battery packs?

I just finished a solution for a severely dyslexic person who had issues dealing with batteries so we built a unit that uses 20v battery packs (from his preferred tool company) so we powered he e-bike by grouping these into a block and then letting the internal protection provided by the manufacturer of these units to manage them, he ended up with a 40v system with roughly 12Ah
It is a weird system but he was worried about hooking everything up right, now he just yanks the packs and pops them in the chargers, just like he does ever night after work. This is a viable solution and in the case of what I built. I recruited a design sparky (Electrical Engineer) who gave his seal of approval on my weird arse design and off to the races. It may fail spectacularly at some point, but it handled testing and it has been like 10 days so far, so good.

So that path is viable. I will happily look at the stats of the battery packs in question to see if they work the same as the ones we used. I ain't a sparky, but I can in fact read and have just been through all this.

If you are looking at buying/stripping/rebuilding... then where you get the cels from ultimately only matters in how good the cels are and how much time you want to put into it.