Building process E-Freeride bike

First a little introduction:
I'm Enpro a 29 yo electronics and bicycle fanatic from the Netherlands with too much free time on his hand.
A while ago i noticed this video about the stealthbike (I'm sure everybody knows what i'm talking about but its basicly a DH/freeride bike with a motor or a silent lightweight dirtbike) and i was about to buy one untill i saw the price tag...
So now i'm going to build one of my own
With this
this
http://www.devi-motion.com/webshop/bldc-hub-motor/p-1/D1000443.html
and this x2 http://www.devi-motion.com/webshop/battery/p-1/D1000425.html

I already have the bike, the motor is on the way but the battery packs thats the main reason why i'm here.
I have a little basic knowledge about electrical circuits but my main concern right now is the batterypacks/s
I got about 800euro / 1100 dollar? for a powerful solution so suggestions are more then welcome.


(moderator edit: moved from Ebike Reviews and Testing, as this is not a review of anything, but rather a build thread)

I like that bike. I noticed the bike is on a train, and there is a little sign with a drawing of a bike mounted on the wall. Is there a way to secure the bike to the train during travel? There is a light rail transit project being discussed for my city, I hope it will accommodate bikes.
The motor you have ordered appears to be able to handle 35 amps continuous. I recommend that you check that the battery you choose is capable of this. If you are familiar with electronics I would consider Lipo, or cellmans A123 packs. I found it frustrating to run my HT3540 with a ping 48V 15AH battery, Lipo is more fun, less worry about killing the battery.

Yes most trains in the netherlands do have a belt to secure the bike but this one didnt.
The best thing is that once i completed this bike i will stil be able to take it on a train because its still a bike
I like to run it at about 30mph but with a lot of torque so i guess that means i need to get somewhere around 40v and a lots of ah right?

I ran at 54kmh with the 48V 15Ah ping and a 9C 2806, with the CA current limit at 25 amps, but acceleration was slow and hills required high speed or lots of pedaling.
With the HT3540 I get 1kmh per volt, presently running 18S 15Ah zippy Lipo at 30A. Much more fun, and safer in traffic.
I am not familiar with the motor/controller you ordered, but after reviewing the specifications I think you should get a battery that can supply the maximum power the controller can handle; 48 volts, 35 amps.

So lipo have a faster discharge rate then li ion and thats why they give more amps?
My original plan was to get 2x 36v 18ah LiMn2O4 (not sure if they are li-ion's or li-po's?) packs and make them parallel/series switchable but would they give me enough torque?
I mean would there be a difference in torque if i run them parallel instead of getting high speeds at 72v?
And if i cap them at 60v would i automaticly get more ah out of them?

Okay after some research i found out that the discharge rate (The "C number" still not sure where the c stands for) is what makes the difference in the wattage and amp the motor and controller can pull out of the accu pack.
25c should be enough for 35 amps continuously.
I also found out you cant pull more then the C nr. or your pack will die.
Unfortunately the original 36v 18ah LiMn2O4 pack i wanted to get dont give info on C nr's what so ever so just to be safe i go with 12x 5.0 5000mah lipo packs with a 20c rating.
Starting the Assembly of the back wheel with the magic pie 3 this weekend.
http://imageshack.us/photo/my-images/600/20111229143102.jpg/

Not sure how i'm going to secure the axle here.
http://imageshack.us/photo/my-images/507/20111229143036.jpg/

Magig pie 3 axle is 14mm so it should fit right?
http://imageshack.us/photo/my-images/401/20111229143133.jpg/

keeping you guys up to date.

More pics to come

The bike is good to build fast and powerfull.

Build thick steel torque plates to secure the axle in the droputs.

Try to place your batteries in the front enough, so their weigh compensate the weight of the motor, to keep the original balace of the bike as much as possible.

If you Magic pie is the one with external controller, buy a programmable controller. You are likely to want more power soon, Lipo batteries and programmable controller let you temper with speed and power, by changing your volt and Amp setup.

As far as i understand this magic pie has an internal controller but it is programmable by a usb cable.
I have absolutely no idea how this works but i going to find out seen enough.
Steel torque plates is going to be a challenge for me to produce because i only have a couple of drills and a dremeltool but not impossible 8)

Well, you'll need an angle grinder and some files, easy to borrow, and not expansive if you need to buy.