# Building E-Bike with E-Backpack



## Pirape (Feb 26, 2009)

Hi, I wanted to build an electric car but I know too little about them so I decided to start with an E-Bike.

The project has begin. As said in Endless forums I will be using my new bike.

The concept is to build a bike that looks completely stock or unmotorised.
but actially having it going 50km/h or faster. Having a backpack filled with batteries.










I will add this rear brushless motor wheel










with hidden wiring in the frame

getting power from 4 of these 10s 5AH Lithium polymer










Safely wraped in Lipo sack than secured in a styrofoam thin block










to finaly insert the styrofoam in this thin backpack


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## Pirape (Feb 26, 2009)

Check list

*Donor Bike: Norco - Check*
Controller: Lyen's eddition 100v -
9c Wheel Motor: Ebikekit.com - 
*Backpack: Built Large Backpack - Check*
*Styrofoam: Insulation styrofoam - Check*
Lipo Sac:
*Connectors: 50 amps connectors - Check*
Batteries: Turnigy nano-tech 5AH 37v -
Cyclers analyst: ebikekit.com - 
Throttle: ebikekit.com - 
*Front disk brake - Check*
Rear disk brake - Ebikekit.com -
*Charger: Hyperion duo - Check*
*Power supply: CPU 20 amps - Check *


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## Woodsmith (Jun 5, 2008)

Interesting packpack idea.

Will it be better in some way then having it in a pannier on the bike?


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## Pirape (Feb 26, 2009)

Woodsmith said:


> Interesting packpack idea.
> 
> Will it be better in some way then having it in a pannier on the bike?


Well kinda. I want a stealth setup and this backpack you can wear a coat over it.

Over here the rules are maximum of 32kph I want a conversion that no one will notice that it is electric.

Also I cant wait to see the faces of those running 49cc scooters when I follow them on a "normal" pedal bike 

One more thing that makes my backpack interesting is that I will use it for other applications such as my lawn mower, hedge trimmer, blower, and weedwacker. 

Maybe some has other ideas of what to do with my backpack
I will have 6 batteries of 37v 5AH

110v 10AH pack
74v 15AH pack
37v 30AH pack

Maybe powering my Iron man's custume?


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## Anaerin (Feb 4, 2009)

Pirape said:


> Maybe some has other ideas of what to do with my backpack
> I will have 6 batteries of 37v 5AH
> 
> 110v 10AH pack
> ...





Tony Stark said:


> If my math is right - and it always is - three gigajoules per second.


1w=1 J/s, therefore 3 GJ/s = 3GW

3GW / 110v = 27,272,727A/s = 1,636,363,636Ah.

Which makes a battery pack of 1,963,636,364 cells (6s327,272,728p).

I don't think you'll be powering a real Iron-Man suit. 

Oh, and amusingly, 3GJ is about equivalent to the chemical energy in half a barrel of oil.

Moving on. 74V 15Ah would give 3,996KW of stored energy (74 * 15 * 3600). Assuming 400W for an e-bike (Travelling at 40Km/h), that gives a range of 9,990 seconds, or 2.775 hours (111Km) of travelling time.

That's a very healthy number, and I think there may be something wrong with my math, as it sounds suspiciously too good to be true. On second looks though, it might just be right:

400W/74V = 5.4054A, 15Ah/5.4054A = 2.775h. 40Km/h * 2.775h = 111Km


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## Pirape (Feb 26, 2009)

Anaerin said:


> 1w=1 J/s, therefore 3 GJ/s = 3GW
> 
> 3GW / 110v = 27,272,727A/s = 1,636,363,636Ah.
> 
> ...


AHHH you mean I have to trash my plans for my robot outfit? Shoot lol 
anyways, your maths looks nice but is none of what I had in mind lol

I thought this was how I had to calculate my km

Avg bike consumption is, at max speed, 20WH
so I did:
74volts x 15AH = 1110WH x 70%DOD = 777/20Whm = 38.8miles x 1.6 = 62KM

Where's my mistake?


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## Woodsmith (Jun 5, 2008)

Pirape said:


> Well kinda. I want a stealth setup and this backpack you can wear a coat over it.
> 
> Over here the rules are maximum of 32kph I want a conversion that no one will notice that it is electric.
> 
> ...


Stealth EV! I like it.
I also like the idea of the battery pack being used for other things.

I have thought of making a battery pack on a belt for working at height with big battery tools. Same power but less weight in one hand while hanging onto the ladder.
I may have to buy into your battery back pack idea.


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## Anaerin (Feb 4, 2009)

Pirape said:


> AHHH you mean I have to trash my plans for my robot outfit? Shoot lol
> anyways, your maths looks nice but is none of what I had in mind lol
> 
> I thought this was how I had to calculate my km
> ...


Where did that 20WH figure come from? it is very strange to measure power used (an instantaneous measure) in timed increments. Akin to saying "This bath is 20 cups an hour full".

I got my 400W figure from http://www.ebikes.ca/faq.shtml#quiz4:


http://www.ebikes.ca/faq.shtml#quiz4 said:


> To maintain nice speeds over 30 kph while going uphill requires on the order of 400-500 watts or more. On the flat, 400 watts (about 1/2 horsepower) will move a typical bicycle about 40 km/hr.


And based my calculations on that.


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## Pirape (Feb 26, 2009)

Anaerin said:


> 1w=1 J/s, therefore 3 GJ/s = 3GW
> 
> 3GW / 110v = 27,272,727A/s = 1,636,363,636Ah.
> 
> ...


Thank you anaerin. It shows how much I know about science lol


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## Pirape (Feb 26, 2009)

Woodsmith said:


> Stealth EV! I like it.
> I also like the idea of the battery pack being used for other things.
> 
> I have thought of making a battery pack on a belt for working at height with big battery tools. Same power but less weight in one hand while hanging onto the ladder.
> I may have to buy into your battery back pack idea.


Woodsmith, I am really active on another forum "endless-sphere.com"
and I got to say you are the only one that likes the back pack idea...

Most say it's too dangerous or really really stupid. For me, it's inovative and fits my lifestyle. It will be really safe with all the precaution I will be taking.

In the R/C industry we are all recommended to use LIPO sac when charging or storing LIPO batteries. Lipo sac are fire safe and they are made from fiberglass cloth. In other words, I will secure every batteries in in that cloth and at the end I will place the styrofoam in that cloth with a thin aluminum sheet securing my back. I dont think it will be that dangerous 

BTW: The new Hybrid hyundai sonata has LIPO batteries lol


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## Woodsmith (Jun 5, 2008)

Well, when I first saw your back pack I did wonder about the safety aspects. Then I figured that you would have suitable fusing to prevent fault overload when in use and you wouldn't be silly enough to charge it while you are wearing it.

Other then that, I am sure that there are some risks involved but I am also sure that you can ask/get information on what may cause the risk level to rise and make an informed judgement on what precautions you may need to take.

Alternatively I could just be really, really ignorant of the risks involved.


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