My first eBike build: DH 2WD in China

shenzhen_ex · Aug 5, 2013

For the last 2 months I have been piecing this eBike together from Taobao with some fabrication required. I decided to go with 2WD. I asked for advise here on E.S. for a few of the details along the way and the response has been unbelievably helpful.

This is going to be an awesome hobby!

I ordered a 48v 20ah A123 battery pack today. Hope this thing runs.

spinningmagnets · Aug 5, 2013

Welcome to ES! Your E-bike is very well done.

shenzhen_ex · Aug 5, 2013

spinningmagnets said:
Welcome to ES! Your E-bike is very well done.

Thanks spinning.

I have mixed feelings about finishing my E-Bike. For the past 2 months I have had something to design, something to build, and a ton of meaningful research to do on-line to get this build done. I really want to build another E-bike after I get this one running well.

The LBS here has a recumbent that he doesn't know what to do with. I was thinking that if I put 3-5 flags on the back, spread out like peacock tail feathers, that it might be safe to ride an E-recumbent in China.

teklektik · Aug 5, 2013

I've seen some shots of your battery mount in other posts - maybe you could re-post shots here and describe how the box mounts up and is held in place...

shenzhen_ex · Aug 5, 2013

teklektik said:
I've seen some shots of your battery mount in other posts - maybe you could re-post shots here and describe how the box mounts up and is held in place...

teklektik, Thanks for asking. My battery box is way over designed but at least I wont have ever to worry about it flying off :oops:

.

I think the images describe how it works better than words.

If you look closely at the first image in this thread you can see the small holes where a pin captures the box mounted blocks to the fork stanchion mounted blocks.

cassschr1 · Aug 5, 2013

Man thats nice. Very interested in the hill climbing ability of this bike. Will be watching.

shenzhen_ex · Aug 5, 2013

cassschr1 said:
Man thats nice. Very interested in the hill climbing ability of this bike. Will be watching.

Thanks cassschr1....But I have no Idea how this this E-Bike will climb yet. I should know this weekend after my battery arrives. I will post the results.

It has 24" rims.

sk8norcal · Aug 5, 2013

cool, subscribe.

shenzhen_ex · Aug 6, 2013

sk8norcal said:
cool, subscribe.

Thanks sk8! I will let you know how it runs.

mattrb · Aug 6, 2013

Amazing bike!

shenzhen_ex · Aug 7, 2013

mattrb said:
Amazing bike!

Thank's Mattrb, your comment means a ton. Chinese people are calling me "insane" for this build.

I see that you are also new here. This forum is an amazing resource for noobs, I am just a bit concerned that the old time members here don't remember what it was like to know nothing about eBikes ( BTW, I speak for myself).

Below: A pic of my 3rd kill switch. Kill switch # 1 is way out of focus in the lower right corner.

sk8norcal · Aug 7, 2013

hey shenzhen-ex,
when you are done, you should let this guy try it,
a vblogger that i follow...
http://endless-sphere.com/forums/viewtopic.php?f=10&t=20160&hilit=+shenzhen

shenzhen_ex · Aug 7, 2013

sk8norcal said:
hey shenzhen-ex,
when you are done, you should let this guy try it,
a vblogger that i follow...
http://endless-sphere.com/forums/viewtopic.php?f=10&t=20160&hilit=+shenzhen

Sk8...Unfortunately I can't watch the video (YouTube is bl0cked here). I will check it out the next time I am in Hong Kong.

shenzhen_ex · Aug 8, 2013

my rear axle snapped within 20 seconds.

MAGICPIE3FOCUSPOWER · Aug 10, 2013

Well done!
Build looks very clean and pro! :mrgreen:

teklektik · Aug 10, 2013

shenzhen_ex said:
my rear axle snapped within 20 seconds.

Ouch! Really sorry to hear that... I'm unfamiliar with those motors, but at only 48v and half the load (2 motors), that seems really surprising....

Just out of curiosity, did you set the controller block time to 0.1sec to essentially disable the initial 'unrestricted current limit' operation? If not, then the programmed 30A limiting may not have been in play (yet) if you went WOT off the line. Just a thought....

litespeed · Aug 10, 2013

Well that sucks!

Do you think too much torque or bad quality?

Tom

shenzhen_ex · Aug 10, 2013

teklektik said:
shenzhen_ex said:

Just out of curiosity, did you set the controller block time to 0.1sec to essentially disable the initial 'unrestricted current limit' operation? If not, then the programmed 30A limiting may not have been in play (yet) if you went WOT off the line. Just a thought....

Click to expand...

I did not set the controller block time limit. I do not think my controller is programmable.

shenzhen_ex · Aug 10, 2013

litespeed said:
Well that sucks!

Do you think too much torque or bad quality?

Tom

Tool much torque:NO
Bad quality: Maybe

Actually I think that I may not have had the adapter on the left (see image below), and the nut on the right tightened sufficiently.

jansevr · Aug 10, 2013

i think the main problem is the poor quality of the axle...which is really too bad because this looks like a well thought out build and a very clean looking setup!

shenzhen_ex · Aug 10, 2013

jansevr said:
i think the main problem is the poor quality of the axle...which is really too bad because this looks like a well thought out build and a very clean looking setup!

You got me thinking...."if i replace the axle it will break again"....

Maybe I should build another adapter on the broken right side, similar to the one on the left in the image above.

Like this.......

jansevr · Aug 10, 2013

this might be possible...a combination of the adapter and possibly some dp420 (the epoxy doc recommends for his torque arms that he has sold quite a few of) might work. its hard to see in the picture, but would also depend on where the axle broke. did it break close to the middle of where the "adapter" would be? this would probably be ideal, but if the axle is so soft and prone to breaking to begin with - it is still questionable how long a fix like this will last.

kfong · Aug 10, 2013

Nice build. Sorry to hear about the axle issue.

shenzhen_ex · Aug 10, 2013

kfong said:
Nice build. Sorry to hear about the axle issue.

kfong, thanks. And I will work out the axle issue!Thread I created to seek help with my axle issue

cassschr1 · Aug 10, 2013

I didn't look at the links in the posts but I feel you just had some bad luck there.

My first eBike build: DH 2WD in China

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