Powerful e-bike commuter/runaround for hilly area

[shonik]

Hi all,

First post after lurking for the past month reading up on stuff. I'm moving to an area which will be 20 mins 1/1.5 miles up a 7% gradient to my nearest train station, and next to no buses, so decided to build an ebike to commute to/from the station, and also generally as a run-around alternative to a car. For speed, I'm happy with 30-35mph on flats (40 would be great but would really be for really short bursts), but the key requirement is wanting to hit 25-30mph comfortably on the hills around where I live. Generally the terrain is a lot of up/down hills, with some flats in between.

After some research, my current plan is:

Motor/controller: BBSHD + ASCI 800 controller, something like this kit, but likely I'll get an eggrider - https://www.electroncycles.co.uk/produc ... ler-45mph/. I initially considered getting a 3000W QS205, but wasn't keen on the additional weight, and I feel there is literally know way to make it look road legal here in the UK, whereas at least with the BBSHD I could run it in a low power setting when necessary (with a 250W sticker

) and probably get away with it.

Battery: I'm planning on building my own 20s4p with LG HG2 batteries, which I'll put in the G80 hailong shark case - https://www.aliexpress.com/i/4000157438415.html. Should give me 72v 40A 12ah continuous easily.

Donor bike: This is where I'm stuck at the moment, reading around it seems given this bike could hit 35mph-40mph, a full downhill bike would be the most reliable/safe. I was initially considering the Giant Glory 2013, but seems like G80 wouldn't fit in the triangle, and I'm worried there wouldn't be enough clearance to mount below the downtube. I'm now considering the Mondraker Summum 2012 (looks like ample clearance to mount on underside of downtube), or Vitus Dominer 2017 (maybe not in triangle, but looks like more clearance below downtube than glory) as I can get both with decent spec fork/shock/brakes for a decent price.

What do people think of my current plan? Any suggestions on the donor bikes I've listed or others I could use? Any suggestions/advice is massively appreciated!

 

[Woosh]

don't go there. You want to build an electric motorbike, you need to start with a bike that is suitable for future type approval. Check the specs of GreyP bikes, they went through type approval: suspension, dual circuit hydraulics, indicators, kickstand, number plate, lighting etc.

 

[shonik]

So basically you meant stick to 250W? I was considering just getting a standard BBSHD kit for now otherwise and seeing how that goes... not sure if it makes sense to go DH for that though?

 

[Woosh]

So basically you meant stick to 250W? I was considering just getting a standard BBSHD kit for now otherwise and seeing how that goes... not sure if it makes sense to go DH for that though?

no, I don't mean stick to 250W. The BBSHD isn't 250W labelled anyway.
If you build anything with more than 48V (13S), you need to take a lot more precautions for your own safety beside space for a number plate and lighting.

There is an interesting article about Belgium 'Moped Class P'

European symposium on speed pedelecs: obstacles & opportunities – Pedelecs – Electric Bike Community

www.pedelecs.co.uk

Who knows, our government may follow it because it's a pretty sensible solution.

 

[RobF]

Buy a petrol moped, although even that might not hit '25-30mph comfortably' on hills.

 

[sjpt]

our government may follow it because it's a pretty sensible solution.

or is that a non-sequitur?

I can see a big benefit of speed pedalecs for some users (especially commuters); but with big reservations. The article mentioned “creates risk for speed pedelec riders” More to the point is whether it creates risk for regular bike riders, horse riders, and pedestrians. I think their use should be very limited on shared pedestrian/cycle paths including bridleways; and on cycle patch that are not pretty wide (much wider than almost all UK cycle paths).

 

[Woosh]

or is that a non-sequitur?

I think the basic idea is this: manufacturers would fit 350W and 500W motors to their S-pedelecs. In their tests, users reported averaging 20mph for 350W and 23mph for 500W bikes. So the bikes are not particularly powerful. Type approval would not be required.
Users still need to be registered, insured and wear a helmet. However, some concessions may be considered: access to cyclepaths if switched to limited speed, s-pedelecs when sharing roads with cars, throttle is allowed for safety reasons.