Making my bike legal

[Ahmed-aomk2000]

Hello all,
I am in urgent need of your help. I am building an electric bike for my end of year school project and i came across a frustrating complication. In Australia the legal requirement is that the electric bike runs at 250W, however as im sure you all know building a 250w electric bike is a waste of time. I was thinking of having a 500W motor kit, with as speed limiter so like a switch for on road use (250W) and of-road use (500w). the bike has to be legal because its for school Im looking at this kit.

http://www.ebay.com.au/itm/Electric-Bicycle-Cycle-Bike-Conversion-Kit-Rear-Wheel-48-Volt-500W-500-Watt/132132014775?_trksid=p2481888.c100675.m4236&_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20160908105057%26meid%3D99c3cdc2e6bb405d85891717606eeaa3%26pid%3D100675%26rk%3D2%26rkt%3D15%26sd%3D172581094633&_trkparms=pageci%253A5ab09755-5c79-11e7-aa8e-74dbd1801ea1%257Cparentrq%253Af1d9ae3615c0aa162810e1d5fffe1019%257Ciid%253A1

He said he will do it for 640. Is there a way i can make this capable of outputting 250W and 500W, and being able to switch between the two

P.S the display has 3 buttons low medium and high

Thanks in advance

 

[TheBeastie]

A strictly enforced standard EN 15194 250W standard ebike is difficult to make faster, as far as I know the motor is supposed to be marked as 250W and the weight of the ebike has to be under a certain limit and you can not have any throttle attached to your bike other than the PAS sensor.

Also that motor in that kit is a direct drive motor, they tend to go faster when up and running but take longer to actually get up to speed when starting from the lights compared to a geared hub motor.
If your travel involves a lot of traffic lights or stops and starts a geared hub motor would be better than a direct drive motor.

The problem I see is when folks go way over the limit and have practically an electric motor bike complete with throttle, I am sure they are having fun but folks like that bring on attention from police for "crack downs" like what have just had on monkey bikes where they crush the bikes, surprised its not on youtube but it was on all the local news TV the other day with the video of them crushing all these monkey bikes..
http://www.heraldsun.com.au/kids-news/news/premier-daniel-andrews-to-introduce-new-laws-to-crush-monkey-bikes/news-story/6e5667fe7f566154f4f2870622472794
http://www.abc.net.au/news/2017-05-30/caleb-jakobsson-sentenced-over-monkey-bike-death-carrum-downs/8570490
https://endless-sphere.com/forums/viewtopic.php?f=3&t=84154&start=100#p1287807

If you manage to kill someone with your ebike I am sure they will have a long hard look at exactly what your ebike is like this guy in Australia Canberra whos ebike got seized.
http://www.canberratimes.com.au/act-news/act-police-seize-electric-bicycle-involved-in-fadden-collision-with-10yearold-child-20170513-gw47o5.html

I use what is commonly referred to as a "kt-lcd3" type ebike chinese kit, with a S12S sinewave controller that is rated for 500W, on a 500W geared hub motor. So I am technically double the limit.
The kt-LCD3 is pretty cheap for the amount of features and controllable options you get.

When it comes to strict 250W standard to be honest there is probably a 50/50 mix? of proper 250W standard ebikes vs ones that go over in Melbourne. Some look close but half-way-there-chinese ones while the more expensive brands that are complete bikes sold in stores tend to be pure 250W standard.

https://www.youtube.com/watch?v=rvil32_gDDc
As this KT-LCD3 video on youtube shows you can use the buttons to adjust the wattage of "Assist" from 0-5 levels (zero gives zero assist).
If I go to level 2 on assist on the LCD display my wattage is goes below 250w.
I normally have it on level 4 which gives about 500watts of power and just dry pedal (empty effortless pedal).
With this kind of LCD/controller setup you can put in difference sized batteries like 36v or 48v etc and the controller automatically deals with it. When you use one of those more basic LED kits they tend to be hard wired to a specific voltage so if you decide to upgrade or downgrade your battery its most likely not going to work with the LVC shut off and many other things..
More specifically the C5 option allows you to control amps going to the motor on a more granular level. https://youtu.be/rvil32_gDDc?t=3m37s

 

[LewTwo]

So you are saying that the 36 volt 250 watt e-bike I have been riding for past year or so is useless?
Well come to think of it; only the motor is rated at 250 watts. The controller is 36 volts x 15 amps = 540 watts.
The limit in my home state is set to 20MPH on level ground without pedaling.

My point being that that the controler is what actually determines the wattage going through the motor. At 48 volts that would have to be limited to 5 amps (48 volts x 5 amps = 240 watts). The wheel can still spin just as fast. It is the power you have to limit not the speed. A more practical implementation might be 24 volts x 10 Amps = 240 watts which is probably what the people writing law had in mind when they crafted the limit.

The controller that you are looking at has is rated at 11.2 Amps and Maximum of 22 Amps. How exactly do you plan to limit it to 5 Amps?

What exactly do the people judging the legality look at?
.. The power rating stamped on the motor?
.. That rated power capacity of the controller?
.. That maximum power capacity of the controller?
.. The actual no load wattage used?
.. The actual full load wattage used?

I have also heard tell of laws that specifically prohibit a switch of the type you suggest.

 

[dogman dan]

Locking this one, because its a duplicate. Discuss further on the thread in e bike general section.