My mid-drive E-Skooter

armandd

100 W
Joined
Jan 18, 2018
Messages
110
Location
Malaysia
*UPDATED*
It's rolling now (by foot, electrics not installed yet). :wink: The foot peg mount is temporarily installed, I will be making a proper one from aluminium.

2019-06-13 13.24.11.jpg

Hi guys. I'm Armandd from Malaysia. I just wanna share some pics and details about my e-scooter build, which I plan to use as a commuter. My workplace is only about half a mile from my home. It's only about 50% completed at this moment. The chassis is made from bicycle parts welded together and the battery box is a stressed member of the chassis. I use 13 inch wheelbarrow wheels and tires mainly because they are dirt cheap to purchase and replace (only 6.32 USD per piece). However, they do create some issues which I think I can solve. Here are the specs:

Chassis: No suspension. Mainly steel, some extruded aluminium and hard wood. Some welded together bicycle parts.
Motor: Unite Motor 24V 450W DC geared brush motor. 420rpm no load speed, 395rpm with load. 10Nm at the output sprocket.
Controller: Yiyun 500W 24V or 800W 36V (can't decide yet).
Drivetrain: Chain drive, 420 size bicycle chain. Front 16t freewheel sprocket, rear 17t single speed sprocket.
Battery: Sealed Lead-Acid SLA 12V 7.2Ah x 4, 2s 2p (I plan to upgrade to 18650 lipo cells later, when my budget allows).
Brakes: Cable operated discs, 203mm front, 160mm rear.

Some mock-ups.

20180103_103240ed.jpg

20180103_103348ed.jpg
 
I have one question: Can I overvolt the 24V motor to 36V? Will this really affect the life expectancy of the motor? :?:
 
Recently I painted the handlebar stem black, changed the floor board to a bigger one, and lowered the ride height. I think it looks much better like this.

2018-02-16 16.23.20.jpg
 
armandd said:
I have one question: Can I overvolt the 24V motor to 36V? Will this really affect the life expectancy of the motor? :?:

I put a 36v controller on one of those motors and it's working well after about 50 miles so far including steep hill climbs. I'm using a small lithium ion battery, you could lighten your overall weight a lot by using a small 36v hover board battery pack (be sure to get one with quality name brand cells if possible, not Chinese cells).

Search threads by Drkangel on here to learn a bunch about modding and operating those motors, very imformative and I've learned a bunch about using the Currie type motors (which yours is).

Are you leaving the Wood stem holding the handlebars on there or is that for a mockup to make a steel one? Whichever make sure they are secure and your handlebars won't slip while you're riding. Interesting project, good job, I like it!
 
Edit:duplicate post
 
Raisedeyebrows said:
I put a 36v controller on one of those motors and it's working well after about 50 miles so far including steep hill climbs. I'm using a small lithium ion battery, you could lighten your overall weight a lot by using a small 36v hover board battery pack (be sure to get one with quality name brand cells if possible, not Chinese cells).

Search threads by Drkangel on here to learn a bunch about modding and operating those motors, very imformative and I've learned a bunch about using the Currie type motors (which yours is).

Are you leaving the Wood stem holding the handlebars on there or is that for a mockup to make a steel one? Whichever make sure they are secure and your handlebars won't slip while you're riding. Interesting project, good job, I like it!

Thanks for the tips. Seems like these little motors can take 36V :D . Yeah, I'm planning to use lipo packs later on, together with better controllers. I have a 24V 500W version and a 36V 800W one. The 24V controller has 20.5V low voltage cut-off (LVC), while the 36V one has 31.5V. Both are not suitable for lipo packs as they will let the pack voltage to go too low (irreversible damage!). There's so many sellers out there on aliexpress, alibaba etc. Do you have any recommendations?

I quite like the wood stem, as it's made from tropical hard wood. Sturdy enough I think.
 
Measured this scooter for the first time and a bit amazed it's 158cm long from end to end! :shock:

Seat height is 88cm, for sure I will make it lower later.

I put a 1.5 liter water bottle for scale.

2018-02-19 21.20.11.jpg
 
Remember Lipo packs ( MultiStar etc) packs need special chargers and you need to know what you're doing with them (I don't) because they are have a potential to cause nasty fires and explosive reactions if they are not charged and discharged correctly. A easier alternative would be one of these (very good deal, I bought one):

https://m.ebay.com/itm/Panasonic-NCR18650PF-2900mAh-36V-Rechargeable-Li-Ion-Batteries-Battery-Pack-NEW/152901180160

You could probably ride 10 miles easily with the above battery, I'm doing just that with a 50 lb bicycle with the same motor.
Or there are a lot of 36v Lithium Ion hover board packs on eBay as well, just be sure and find one that claims GENUINE cells, LG, Panasonic, Sanyo etc. Generic Chinese cells are notorious for potential problems and also fire potential.

36v lithium ion chargers are widely available and cheap on eBay, amazon, etc at $4.99 to $20.00, good to have a spare in case one dies at that price. Yeah I like hardwood too, you should see the knife handles I've been making with Hawaiian Milo and Koa recently, together with Japanese AUS-10 blades they are very flashy Paring Knives, very useful in the kitchen. Gave one to my mother-in-law since she bought me a very expensive handmade folding pocket knife last year.
 
Raisedeyebrows said:
Remember Lipo packs ( MultiStar etc) packs need special chargers and you need to know what you're doing with them (I don't) because they are have a potential to cause nasty fires and explosive reactions if they are not charged and discharged correctly. A easier alternative would be one of these (very good deal, I bought one):

https://m.ebay.com/itm/Panasonic-NCR18650PF-2900mAh-36V-Rechargeable-Li-Ion-Batteries-Battery-Pack-NEW/152901180160

You could probably ride 10 miles easily with the above battery, I'm doing just that with a 50 lb bicycle with the same motor.
Or there are a lot of 36v Lithium Ion hover board packs on eBay as well, just be sure and find one that claims GENUINE cells, LG, Panasonic, Sanyo etc. Generic Chinese cells are notorious for potential problems and also fire potential.

36v lithium ion chargers are widely available and cheap on eBay, amazon, etc at $4.99 to $20.00, good to have a spare in case one dies at that price. Yeah I like hardwood too, you should see the knife handles I've been making with Hawaiian Milo and Koa recently, together with Japanese AUS-10 blades they are very flashy Paring Knives, very useful in the kitchen. Gave one to my mother-in-law since she bought me a very expensive handmade folding pocket knife last year.

Here in Malaysia we have abundance of tropical hardwood. Meranti, Jati, Chengal, Nyatoh, Keruing etc to name a few. All have different grains, and very lovely when finished in laquer :p They are very hard. The Chengal type is so hard that it will split if you even use small nail and termites couldn't sink their teeth into it!

Back to the scooter. I plan to stick to 24V for now to extend the life of the motor. What is your opinion on LiFePO4 battery packs? I know they are much safer than LiPo or Li-Ion cells. I found this LiFePO4 24V 12Ah pack online. Costs about 204 USD which includes shipping. Do you think it's a good buy? My controller LVC is 20.5V, this should protect the pack from going under 20V.

http://www.11street.my/productdetail/lifepo4-24v-12ah-battery-with-charger-for-electric-44520934

LiFePO4 24V 12Ah pack.jpg

LiFePO4 pack datasheet.jpg
 
I made a battery box, which is easily detached from to scooter to charge them more conveniently. I will make strap handle and add charge port later. This also enables me to make several packs and just swap them and scoot off if I need to. :lol:

2018-02-20 17.43.12.jpg
 
Rikobonito said:
wooooohoho :D this big toy !!! Love it !
What a perfect custom mode that you made here. (I would love to learn about welding !!.. It will be so help full for my little e-DirtScooter)
Good contnuation, I stay around ;)

Hey thanks for the encouraging words! :lol:
 
Designed a relay control board with blinker circuit for head light, turn signals, rear and brake lamp and horn using Proteus software.

relay circuit pcb.jpg
relay circuit 3D.jpg
 
Armand-This is a very interesting project! I think the LifeP04 battery you posted above would be a very good thing, a comparison between the weight of your current SLA's, that battery I'm guessing will result in a huge difference between the two and with that ah rating you'll be able to ride quite a ways, probably find yourself just going out for rides for no reason except for the fun of it.

It sounds like you have some amazing hardwoods there, now I have to look up some of those and see what they look like!

Sticking to 24v for your scooter is probably a good thing, I have one with the exact same motor at 24v and on flat ground it goes pretty fast, although if I boosted it up to 36v it would go up steep hills much more willingly, (as I have discovered with a bicycle using the same motor), get some speed up with the 36v set-up approaching the hill and it will usually keep quite a bit of speed up. On flat ground with a scooter the 36v would go quite fast and be a possible safety issue, I don't heal as fast as I used to at my age he he.

Nice work on the circuit board design, I'll be interested to see further developments on the project.

Yes I would do away with the SLA batteries, it'll will be much lighter and easier to move around and just a more robust battery than those little SLA's
 
Borrowed two of these fat lipos from a friend :lol:. However, they seem a bit puffed up. One is more puffed up than the other. Are they safe to use? I'm not very good with lipos. Their voltages per cell are somewhere between 3.5-3.7V. I have a balance charger, but a bit worried to charge them up. :roll:

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