scooter build

Lightweight / Folding / Portable EVs - seats optional

Re: scooter build

Postby aethyr » Thu Jun 08, 2017 6:28 pm

Update! I've actually been slowly working on this scooter for the past few months, just not a lot of progress, but today, done!

Most of my time was spent building the battery pack. I had chosen samsung 30Qs, which can handle 15-20A of discharge. The problem is that a 7mmx0.15mm nickel strip can only handle about 3A. So after much research and testing, I decided to use 12AWG copper wire to act as my series connections between cells rather than trying to layer 6 0.15mm nickel strips. My 20s6p samsung pack can now legitimately handle 100A of continuous discharge.

I had to do a lot of creative parts bin scrounging from china. The base scooter I originally got from craigslist was too small to house the LR big block. More accurately, the rear frame was too small. So as I've posted earlier, I had to buy the rear frame that EG's scooter has. The problem was, upon receipt, the frame was too wide, so I had to buy spacers and 15mm bolt and grind and customize to get the rear frame to properly fit.

A good friend welded together the motor mount, in red that you can see in the picture.
Image

The chain is 219, as recommended by EG and was easy to shorten using a 219 chain breaker from ebay. I custom designed and 3d-printed the chain guards to ensure the chain stays on.

As you can see, I had no space to for the controller inside, so I mounted outside. Its a kelly KBS 130a.
Image

As for the LR big block. Holy balls. I took it for a spin today. I almost got thrown on my ass from the huge and instant torque. I actually can't give it more than 30% throttle at any time because it will pop a wheelie and throw me on my ass, which is not fun at 50mph or even at 15mph for that matter. I used to have a Yamaha R6 supersport and this scooter is more scary! I don't ever say this, but this motor might actually be too much, lol. The torque is so instant I have to REALLY feather the throttle. Its currently geared to hit 50mph, but I may have to gear it to hit 60 or even 70 so the throttle is actually more usable.

A big thanks to ElectricGod, who as you can see from this thread, has generously given his knowledge and experience, upon which this scooter was built. And Mike's ridiculously overpowered motor, and other's who have helped answer my questions.

I plan to add some more cosmetic details, such as tail lights, headlights and horn, and have my friend weld a cargo platform on the rear frame.
aethyr
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Re: scooter build

Postby Ianhill » Fri Jun 09, 2017 10:27 am

Cracking build how have I missed this, sounds like this sun of a gun is a beast to ride got to be on it or it will be all over you, lucky you have the r6 experience to tame the mini giant ;).
Razor E3000 brushed 12s lipo 3kw viewtopic.php?f=35&t=78948
Stand up faggio EV 3.7kw 16s viewtopic.php?f=35&t=82374&start=75
A2b metro gti viewtopic.php?f=6&t=87836
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Re: scooter build

Postby aethyr » Tue Jun 13, 2017 5:33 pm

Thanks! I'm actually a little surprised everything worked nearly right off the bat. My problem now is that my circuit breakers can't handle the load. I actually destroyed a 100a breaker, so I upgraded to a 200a :shock:

The other little quirk is that my ammeter seems to be reading low. I don't see over 20A under load, which can't be right if I'm popping 100A breakers. I have a 200A shunt.

I also ended up upgrading the front brakes to shimano hydraulics. I didn't think I'd need hydraulics until I experienced how long it took to stop. Now, if I'm not careful, I can flip forward from grabbing too much brake. So I can flip backwards and forwards, if I brake too hard or throttle too hard. Symmetry :)

I still need to wire up my DC-DC step down converter. It was somewhat challenging trying to find a relay that could handle 84V and at least 3 amps on the contacts. But I found one for $11 (but $10 shipping :roll: ) = $20.

I also have this https://www.aliexpress.com/item/20S-50A-2017-new-Li-ion-smart-bms-pcm-with-android-Bluetooth-app-UART-correspondence-bms/32809939362.html?spm=2114.13010608.0.0.NTVGiP "smart", bluetooth BMS on order - I plan to use this just for charging, since its only 50A discharge. I can set the final voltage on the fly - 4.2V for max capacity or 4.1 or less for longevity or anything in between. I plan to keep it charged around 3.9V (50%) capacity and whenever I anticipate a long trip, my 84v/10A charger can bring my 18Ah battery up to 80% capacity in 30 mins, all done on the fly via bluetooh. I can monitor individual balance voltages via bluetooth as well. My controller provides LVC and my 200A breaker/main switch protects against shorts.

I also have this https://www.aliexpress.com/item/Folding-Aluminum-Alloy-Handlebar-Bike-Parts-Foldable-Cycling-Bicycle-Handle-Bar-MTB-Road-Bike-Handlebar-Stunt/32768770757.html?spm=2114.13010608.0.0.5tnqRM folding handlebar on order from China for smaller storage footprint. This particular handlebar can fold pointing down, so that when the neck folds down, everything folds together nicely.
Last edited by aethyr on Tue Jun 13, 2017 5:37 pm, edited 1 time in total. View post history.
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