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Discussion Starter · #1 ·
I was wondering how power assist to the rear wheel works while you're pedaling. Wouldn't you end up spinning the electric motor? Think of a slow electric motor on a power drill. You can't "assist" it by giving it more power by turning it with your hand while it's spinning. There's resistance from the motor. So how does it work on a bike?
 

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What you are wondering about is referred to as pedelec in the e-bike world. It is not necessarily a requirement here in the US, but is mandatory in Japan, Asia and the EU.

Basically a sensor located in the vicinity of the cranks (the different types of motor drives determine the type of sensor whether torque or motion activated) is used that sends info to a controller that talks to the motor. The motor and the human drive are separate entities that allows for the human drive to propel the bike without (much) drag from the motor which allows the bike to be ridden normally if the motor option is off. That is why the motor is not affected while under power by the human drive as per your analogy. Most systems available are pretty well refined as pedelec has been in use now for over a decade.
 

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Discussion Starter · #3 ·
Thanks for the info :)

Here's pics of a Panasonic pedelec system for anyone interested.





It's an interesting system. Downside, it's expensive. You could buy a Honda Ruckus for the price of a pedelec equipped bike. No insurance or motorcycle license required for the Honda.
 

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Not sure where you live but that Honda would require tags, license and insurance in most states. Which really wouldn't be that bad to get ahold of due to it's full complement of DOT goodies. But for that effort I would rather run one of these: http://www.gizmag.com/honda-cb-twister-110cc-164mpg/13593/picture/107048/

But to be fair anything without pedals is a different class of machine. Without pedals you must stay in the vehicle traffic lanes, but with them you can travel in the bike lane. Also if your e-bike is efficient enough you can shut down and travel on interurban trails that don't allow any motor vehicle access, and in some states you can even use them motorized on that type of trail. Here is a vid that I made up a little over a year ago that illustrates this, albeit with a gas motor:
 

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Yep, when you are pedaling with the motor engaged you are essentially just taking some load off the motor (usually about 200 watts if you're working) which allows for more range out of the battery. Instead of consuming 15 wh/mile while not pedaling you may be able to drop it to 10 wh/mile while pedaling. Same principle that allows the Prius to get good gas mileage around town, the electric motor just takes load off the gas motor so it doesn't have to work as hard.
 

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Hybrid System to Solar Charge an Electric Bicycle

There are a few different ways to solar charge an electric bicycle but
this is probably my favourite system; I can use one 48V panel through
a custom regulator to go straight to a lithium ion battery or else I
can use the same panel to charge a battery bank to store the energy
and then use an inverter and the normal battery charger for the bike
battery. I've made a short video to show how to do this and put it on
youtube. You can also access it through my Solar Bike website -
solarbike.com.au
youtube.com/watch?v=Z5j9VyuWNzU
 
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