If that''s a Bafang CST motor, I've run mine at 64v and 30 amps without any problems other than trying to keep traction between the tyre and th road. Bafang are now a serious motor manufacturer. They've been improving over the years. All the things we used to say about their poor quality doesn't really apply anymore. I don't want to sound unsympathetic, but I think you should look more towards the way that the motor was installed than the quality of the axle. I hope you get it sorted soon.
My first eBike build: DH 2WD in China
- Thread starter shenzhen_ex
- Start date
MAGICPIE3FOCUSPOWER
10 kW
I think it's just too much axle space between the motor and dropout.
So more chances of breakage...
So more chances of breakage...
shenzhen_ex
100 W
d8veh said:
Well..I just sent the motor back to the factory for repair. That should sort things out.
dawrench
1 W
Awesome build. Makes my first ebike look like sh*t. Looked so bad no pix survive. In my defense, brushless hub motors and LiPo were not available 20 years ago.
Is it possible to change the axle? Maybe have one machined in 4340? Torque arms on both sides.
Is it possible to change the axle? Maybe have one machined in 4340? Torque arms on both sides.
shenzhen_ex
100 W
dawrench said:
Wow, 20 years ago
What was that bike like? Do you know of a thread dedicated to vintage bikes?samoloh
10 W
do you have a video of your bike running?
shenzhen_ex
100 W
samoloh said:
I don't have video. I will see what I can once I get the rear motor fixed.
shenzhen_ex
100 W
I returned my BaFang CST motor to the place that I purchased it on-line in China.
I did not think it was covered under warranty since I snapped the axle, cut the wires, hack sawed the other side of the axle, and drilled all of the spoke holes.
But they replaced it with a brand new motor for free and got it back to me in 10 days
.
I did not think it was covered under warranty since I snapped the axle, cut the wires, hack sawed the other side of the axle, and drilled all of the spoke holes.
But they replaced it with a brand new motor for free and got it back to me in 10 days
.Attachments
shenzhen_ex
100 W
litespeed
100 kW
Again, very impressive.
Tom
Tom
shenzhen_ex
100 W
. 2 for 2
litespeed
100 kW
So I'm thinking different motors might your next move?
Tom
Tom
shenzhen_ex
100 W
litespeed said:
I would like to have motors with thicker axles (10mm across the flats is too small for a hollow axle). However these are new and covered by warranty so I will stick with them. I just need to build TA's that also support the axle.
REQUIREMENT: This DH must be able to take a beating. Trails, curbs, pot holes.....
litespeed
100 kW
Warranty rocks but just be careful getting to crazy. the warranty wont cover a broken you.....
Tom
Tom
dawrench
1 W
shenzhen_ex said:dawrench said:
Wow, 20 years ago
Back then, some ebikes used flooded automobile or golf cart batteries. Imagine two 20 kg flooded batteries strapped to your bike with 4-9 litres of Sulfuric acid sloshing around. This might take you 12 miles at 15 mph. Some used Gelled acid batteries, a few had these new AGM type SLAs, a very very few ran on NiCad batteries. NiCads were capable of high currents but were VERY pricey for a large enough pack. They also had high cycle life and didn`t mind being run down close to zero.
I still have a couple of 20s1p D cell packs kicking around with life in them.
Motors were brushed DC either series wound or PMDC. I've seen or used golf cart motors, repurposed floor polishers, electric wheelchair parts, fan motors from a Mack truck - even MilSurplus stuff. If one wasn`t enough use two like the EV Warrior.
Controllers were whatever you could find and often had a heat sink the size of a phone directory.
Todays bikes with BLDC hubs and Lithium batts absolutely blow the doors off the vintage rigs.
dawrench
1 W
Here is a site called the Electric Bike Graveyard - these are production bikes not DIY stuff from Popular Mechanics.
http://www.electricbike.com/ebike-graveyard/
And yes, I will start a new thread for this.
http://www.electricbike.com/ebike-graveyard/
And yes, I will start a new thread for this.
shenzhen_ex
100 W
She is running again.
I went for a 20km ride and decided to check the axles for any sign of trouble. I found all the nuts were no longer tight. I checked them several times before the ride. So new moters must have the bearing not fully pressed in. I suspect that contributed to why my axles snapped in the first place. I will check the nuts often until they stay tight.
I love the 2WD...This thing climbs awesome!
I went for a 20km ride and decided to check the axles for any sign of trouble. I found all the nuts were no longer tight. I checked them several times before the ride. So new moters must have the bearing not fully pressed in. I suspect that contributed to why my axles snapped in the first place. I will check the nuts often until they stay tight.
I love the 2WD...This thing climbs awesome!
Attachments
RoadWrinkle
100 W
Your build is so clean; if you have enough torque/power to snap both axles, maybe time to consider a non-hub build...Far be it from me to give you advice, but I noticed in one of your first pics the wire loom coming straight up from your front hub motor. If this is still the case, you could create a "U" loop with a twist tie or a fancy bracket so any water that lands on the wires will run off instead of into the motor's wire inlet. I am sure you are aware of many techniques to ensure your axle bolts stay tight (clamping style TA's, custom axle milling, nord(sp?) washers). Have you taken apart your hub motors to see if they will fit a larger diameter axle? What is your typical terrain and riding style?
shenzhen_ex
100 W
RoadWrinkle said:
I would like to make a non-hub build but the 2WD is a blast.
I really do have to address my wire routing. I will get to it later
Increasing the axle diameters would require a non standard bearing ( I think) or making new side covers. I prefer to get a motor with larger axles next time. This is my first build, I did not even consider axle size when I bought these motors.
I ride off-road and street. Today I was taking small jumps, stairs, and rough trails.
shenzhen_ex
100 W
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