Giant MODEM eBMX

problemaddict

problemaddict

100 mW
Joined
Jul 15, 2016
Messages
43
Location
Hatfield, pa
Hello all,

I got bit hard by the ebike bug after reading Luke's Gizmag article. I've been doing months of research and have just started ordering parts for what I thought would be a quick/dirty intro to ebiking: Throwing a kit at my BMX. Turns out, because of all the BMX quirks, this is going to be a bit more involved. But I am pressing on, regardless.

Here's where we are now:

PXgnho1l.jpg


The plan:

Leafbike 1500w
Sunwin 15fet controller
Echo tool batteries (14s4p)
200mm disc brake
Moped tires
Custom machined dropouts

Out of a mixture of coincidence and influence, i hope for it to end up very similar to Relanium's BMX project.

Stay tuned as I try to make some progress and hopefully get a ride in before the end of the year...

This is not my first mechanical project. I've built several cars and motorcycles in the past. on the two wheel front:

I built this ratbike (ZX6) 10 years or so ago, but its never "done":

OOG6V0Cm.jpg


I've done some scooter racing:

MQ1cdeam.jpg


And I've raced this Blackbird at 167mph at The Ohio Mile:

Zk5pNHpm.jpg


So, I'm excited to add an eBMX build to my resume and hope it will teach me a thing or two. Maybe I'll move on to building an E-motorcycle in the future...

Thanks for all your help so far!! This is an amazing forum full of useful information!
 
Wanted to come back here, update my thread and say THANKS! I got the eBMX running this weekend thanks to the wealth of info on this forum.

So, real quick:


Some confusing mess,

QIgmmAAl.jpg


A bit of crude fabrication,

DF5IHv9l.jpg


a5wAW82l.jpg


My first ever spoked wheel build,

UDwmtSel.jpg


cxpU6kBl.jpg


And that takes care of the front end. On to the rear,

Beefed dropouts,

Zduxfwcl.jpg


Rear wheel mounted and we've got a roller! Started on the wiring,

1oQ2CSgl.jpg


Using a 3d printed plug adapter, designed by forum member: mman1506, for the 58v Echo battery.

DVW6ppLl.jpg


A mess of zip ties and Velcro and BOOM! eBMX prototype, Stage 1

USJbOiWl.jpg


And right out off the box:

7Et9yfJl.png


Bike weighs 52 lbs, 24kg
Pulls 35.5A max at 52v nominal that's 1846 watts
32mph on GPS, 51.5kph
 
Nice bike :D
Leaf motor is much better option than heavy MXUS.
It's powerful, but I never managed to heat it up unless riding in the summer on a hot sunny day.
IMHO too heavy and no need for such power, but leaf is lighter and has much better efficiency.
Have fun on it and ..... wear protection gear always!
Trust me! :(
 
Built a parallel harness and used some hardware store brackets to get up & running with two batteries. Now it's only pulling 15.2A per pack, so that should make them happier/last longer.

Got regen working, but it's much too strong. Locks the rear tire up for a split second every time i pull the lever.

And the Sunwin controller has a 3 speed switch. With no load, the wheel spins allot faster on "high", but when riding its 32mph top speed no matter what speed mode is selected. Not sure what's up with that...

wudpUSUl.jpg
 
New top speed!

cabRw10l.png


High speed mode kicked in randomly today on a ride. Not sure why it doesn't work all the time, but I'm stoked. A 40mph bmx was my goal with this project.
 
I ended up sticking with bicycle rims and maxxis holy roller tires. If/when I go to a moped setup I'll probably get the 16" rims that www.treatland.tv sells.
 
Working on a better battery mount. Got some 4" square fence post and started cutting...

IMG_20170604_171835_883_512x512.jpg

I will round the corners, sand, and paint after a couple test rides to make sure it's sturdy enough.
 
Ouch! That was a nasty crash. Glad it didn't keep you down.

I like the fence post stuff. I'm going to see if they have it at my local hardware store.
 
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