10,000yrs in the making, finished

[m303625]

Just finished my 1st build and am very happy with result, Great full suspension giant bike with hyd disc brakes front and rear.
Bafang geared rear hub motor with 5speed cluster. All under 20kg with Battries included
I have been riding a chinese import with similar bafang motor powered by 36v lion battery, and like most here decided I needed a little more grunt. Tried a modest overvolt to lightweight rc lipo batts at 44v 4ah. brilliant these batteries weigh only a fraction of the original 36v 10ah pack yet can deliver up to 40amps in bursts, of course the downside of these is the range, but for my short commute this is not a problem. Cannot be happier with these batts at the size of the water bottle and so far done 20km on one charge with estimated 1/3 left in them!
So went out and bought a full suspension Giant bike and ordered the motor, controller and throttle from Kewin in HK.
After receiving the goodies I was surprised at the large size of the ecrazyman controllers, and since I am happy with the power from my current chinese import, I ordered a controller from the Aussie supplier, less than half the size but I am running it at it's max limit. over 600w at the wheel allowing for 95% efficiency from the Bafang
Tried the ecrazyman controller on the new bike, quite noisy and not a whole lot more grunt compared with the smaller unit, using my 44v lipo pack, the ecrazyman would need more batt capacity but would definitely be more powerful!
After a test ride and a wiring tidy up all is done, and I am amazed by the amount of human time and expense to produce what appears on the surface a simple machine, firstly the mechanical engineering ,production and refinement of the bike itself, then the electronics with all it's quantum mechanics driven semiconductor components, I know the individual parts are not all that advanced but all combined together I could be riding the most cutting edged piece of technology ever created, hence the title of this post!
btw the expense of a quality bike is justified in my opinion and the gearing worked out spot on, new bike may be a couple of km/hr slower than my import but is definitely more fun to ride!
some pics included

 

[recumbent]

Nice clean build, it's worth the extra time to do it right.

What exactly did you mean when you said one controler made more noise than the other? Did one controler vibrate the motor more?

Welcome to the forum, you've got the most compact hub motor on here, nice and descrete, hope it lasts.

 

[voicecoils]

Very clean, awesome work What sort of performance are you getting?

Are you using your 36v10ah lion pack + lipo RC booster pack, or do you have a 44v dedicated RC pack on it's own?

Sounds like you're running at a safe voltage and overall power not to strip the nylon gears like I did at 72v. (my red bike build)

I noticed you said your in AU, are you in Sydney? Maybe we should have a "bafang meetup" there are already a few of us on E-S living in Oz with these motors.

Cheers!

 

[voicecoils]

What exactly did you mean when you said one controler made more noise than the other? Did one controler vibrate the motor more?

Yes, I wonder about this too. If it didn't sound right, I suspect you had the motor wired to the controller incorrectly. wire colour means nothing in China it seems and there are 36 wiring permutations with only 1 to 3 possibilities that work correctly. I've had great frustration getting mine wired correctly with two different controllers.

 

[m303625]

Hi guys, in answer to your questions,
using 12s 44.4v lipo pack only, look at the pics the small bag under the seat is the batteries, gets min 15km at around 30 to 35km/hr still need assistance up hills but not a lot!
I know it's not the most powerful ebike around but I like to pedal a little and as you say I am wary of too much power for these motors damaging the gears, I have done several hundred kms with this setup on the chinese import bike with nothing more than a more noticeable whine from a standing start, gears I assume!
With the ecrazyman controller it is the motor making the noise, hard to describe sort of high pitch squealing, pitch alters as load changes, no vibration and yes I have got the wiring correct
the smaller chinese controller which you can see in the photos just below the battery bag under the seat, surprisingly has the wiring correct and is almost completely silent
the following measured using watts up meter
max amp 15.5a
max voltage 50v straight off charger
min voltage under load 41v
670w max power measured at the batteries
estimated over 600w at wheel allowing for about 95% efficiency
ps I live Sunshine coast QLD

 

[tailwind]

Great work. I'm impressed with how clean and stealthish the bike looks.
The dual suspension and light weight must make for a great ride.

If I was passing you on the road I would not even suspect you were riding an electric bike.

Greg

 

[JinbaIttai]

If I was passing you on the road I would not even suspect you were riding an electric bike.

Same here. And I check for hub motors in every bike I see on the road. I would never suspect this bike has a motor.
You've got my vote for cleanest, stealthiest build ever.


Are you going to put a picture of it as your avatar?

 

[fechter]

The motor noise will be proportional to the current. If the ecrazy controller has a higher current limit, it will make more noise.

Very nice stealthy build! Lycras won't know what passed them

 

[m303625]

Thanks for the info Fletch,
that makes sense, the ecrazyman controller is rated at 30amp and under testing hit a max of 25amps, unfortunately my 4ah pack is very stressed at these loads and the voltage sags below the controllers cutoff limit after a few seconds.
My current controller is rated at 36v 15amps and is happy to take 50v and consistently deliver 15+ amps, it's not quick by a lot of standards here but very usable and efficient in terms of power to weight, especially given our 200w limit here in Australia
thanks for the compliments guys the stealth look was exactly what I was looking for, can't say enough about lipo cells great power for weight and size, just be sure to take appropriate precautions when charging and keep a close eye on the discharge rate.
it can only get better from here as battery tech improves

 

[Gow864]

Awesome build! WELL DONE.... I want one.

Gow.

 

[Knuckles]

Is that a thread on disc? Where did you get it?

I would love some details on the disc and the brake calipers.

Nice build!

cheers mate,
Knuckles





And More!
http://www.electricscooterparts.com/brakes.html

 

[MitchJi]

Hi,

Nice

Is the suspension pivot point the crank?

Thanks!

Mitch

 

[recumpence]

Looks very clean!

If you want more current with less sag under load, you can move to higher C rated cells. Odds are you have 10C rated cells. If you go to 25C cells, you will see far less sag due to lower internal resistance. RC lipos are AWESOME!

Anyway, I love the bike. Very nice to see some serious attention being paid to make the bike nice and clean.

Matt

 

[m303625]

A note to Knuckles question about the disc brake setup
motor as supplied has been machined to accept direct bolt on for a standard disc
if you want the specs email Keywin (ecrazyman) about it
the caliper is standard on this bike and was not modified in any way, the only thing I had to do is shim the disc the correct amount to centre the disc in the caliper housing
The biggest problem I had with this build is sourcing the 13g ss spokes and getting the length right
had to get them direct from taiwan factory.
been riding the bike for a week now, still very happy with it.
My theory about lipo batteries is "if your arse is on fire then you peddle faster"