Help with my first E-Bike

[cwnj]

Hi,

I have been looking to buy a bike for a while now as a general commuter to get me to the local shops, around to friends houses etc and a bit of fitness but don't want to have to pedal all the time and while I was looking at combustion bikes on ebay I stumbled upon an E-bike. Intrigued I went to Youtube and well...... only took a few clips and I knew I wanted one.

After finding this site and reading a few posts I found there is a lot to think about when building an E-Bike for a total newb like myself (or maybe Its really not that complicated and i'm just doing my head in looking at kits and bikes for the last 2 weeks). Now I know that the legal limit for my location is 250W but to me that's just ridiculous and judging from peoples comments I may as well get a pet mouse and spinner wheel. I don't intend to tear around footpaths and I'm sure the boys in blue will leave me alone as long as i'm careful and don't act like a idiot.

So here is what I want. I don't want to spend more than 2K all up. I have no idea about electronics. Volts, amps etc is all new to me but will learn..... slowly

1. I weigh about 75kg's.
2. Want a cheap bike that's comfortable to ride preferably with a larger wheel
3. Will only be on road but would like it to be able to take a few bumps and bruises ie the odd small pothole and gutter ramps etc.
4. Want to be able to install Pannier rack and bags (put the battery in bag on the rack and carry a few odds and ends in the side bags).
5. Want to be able to go at least 40-50km/h.
6. The max distance I would do is a 20km round trip.
7. There is a few hills around my area. I don't mind peddling but want as much assistance as I can get.
8. Like the idea of an external controller as it gives me the option to tinker with the setup later on down the track.

So here is what i'm looking at.

Bike
http://www.cellbikes.com.au/Cell-2013-Trail-Blazer?sc=21&category=12627
Kit
http://www.goldenmotor.ca/products/700c-Rear-PRO-901-Conversion-Kit.html
Battery
http://www.goldenmotor.ca/products/48V10AH-LiFePO4-Aluminum-Cased-Battery.html

The bikes probably cheap and nasty and would need some torque arms as well as a few other things such as lights and the like..... and most likely something I've missed.

Any help/suggestions would be much appreciated

 

[bowlofsalad]

http://ebike.ca/simulator/ It looks like you may have been playing with this, I don't know. But you sound well read, which is surprisingly rare. However, you were wise to ask some questions.

At those speeds, I'd suggest seeking a used mountain bike with suspension. If you don't want suspension or don't think you can find a used bike like that, aim for a bike with fat tires, fat slicks will be the way to go for you. I don't recommend using an aluminum frame as a base for converting to an ebike. Aluminum has no fatigue limit.

Battery packs have a limited cycle life, in addition to this there are many variables that determine what your watt hours per mile (wh/mi) will be, and lastly, C rating is some that is very important to consider. When you drain a pack to low voltage cutoff (LVC) obviously you are going to have to pedal the rest of your journey, that isn't ideal, but draining a pack to 100% depth of discharge (DoD) compared to around 70% DoD can have a very different effect on cycle life. Basically what I am suggesting is, if your goal is to have 20km of range at your bikes top speed, aim to have, at least, 40km of range available in your pack, wind, cold, hills, stops and starts and so on all will have an impact on range. That webpage for the battery you might buy doesn't mention the packs C rating. C rating is capacity multiplied by the number before the letter C, c stands for capacity in this. So if a pack has a C rating of 1c, and your pack has a capacity of 480 watt hours (amp times volts gives you watts), you can continually and comfortably draw 480 watts without harming the pack or heating it up. If you were to draw much beyond that and above, it would at least not be good for the pack. This is often an issue when people go for very tiny packs, a123 cells might be a good choice if you think your hills are large and your pack will be very small. However, with all this said, you might consider at least 48v15ah packs, but I am sure you'll weigh all the variables.

Some things to own that are probably not optional. A voltmeter or multimeter, a bell, a pack with balance leads (If they don't show the leads in the picture, ask them if they are included, if they are not, either ask them to include them or don't buy the pack), a watt meter, and maybe some spare parts if you can afford them.

I don't know how you intend to mount your battery pack, but when you've settled on it, you might make a slightly larger mock version and put it in various locations in or on the pack to see how it fits. A lot of upright riders put their pack in the triangle but often have issues.

 

[wesnewell]

Bike. Get 26" and make sure it has steel dropouts. That's my only must have criteria. For comfort and stability I always replace the tires, seat, and handlebars. For tires over 2.3" replacing the rims with wider ones gives a better ride too. Frame can be aluminum as long as swing arm is steel. I've tried no suspension bikes and they work well but are rough riding compared to FS bikes. Once yuou put a motoron one, you'll find all those gears are about worthless as you'll likely stay in highest gear 99% of the time, so a 6 speed or more is all you need. Must have a rear freewheel. Not a freehub and cassette.

Conversion kit. You're in Sydney. Makes no sense to buy from Canada. Get this. It's also local if there's a problem.
http://www.ebay.com.au/itm/Electric-Bicycle-E-Bike-Conversion-Kit-Brushless-Motor48V-1000W-Rear-Wheel-Rack-/150956506830
Same motor I've been riding for over 2 years without a problem. Plenty of power for 75kg person. I'm ~125kg.
Basically the same as this.
http://endless-sphere.com/forums/viewtopic.php?f=3&t=49638

Battery. Hundreds of choices. Only one must have criteria. It MUST be able to provide the max amperage of the controller you use. 30A for above kit. I use RC lipo from Hobbyking.com. A 12s pack of 20C or higher is perfect because the LVC of the controller is perfect at 42V. But any type pack with a MAX voltage of no more than 63V will work as long as it can supply 30A. There is an HK warehouse in AU. Order from it if you go with lipo. 12s lipo (44.4V/50.4V) will get a minimum top speed of 45kph. A 10ah 12s pack will cost from $150- $250 depending on how you configure it. Charger and PSU another $100. Now I'll let the lifepo4 and NMC fans have their say.

 

[cwnj]

Thanks for your replies

At those speeds, I'd suggest seeking a used mountain bike with suspension. If you don't want suspension or don't think you can find a used bike like that, aim for a bike with fat tires, fat slicks will be the way to go for you. I don't recommend using an aluminum frame as a base for converting to an ebike. Aluminum has no fatigue limit.

Thought as much with the bike selection. Although there seems to be quite a large price jump when looking at FS MTB's unless you buy it from a dept store. Not that it wouldn't do the job.

Bike. Get 26" and make sure it has steel dropouts. That's my only must have criteria. For comfort and stability I always replace the tires, seat, and handlebars. For tires over 2.3" replacing the rims with wider ones gives a better ride too. Frame can be aluminum as long as swing arm is steel. I've tried no suspension bikes and they work well but are rough riding compared to FS bikes. Once yuou put a motoron one, you'll find all those gears are about worthless as you'll likely stay in highest gear 99% of the time, so a 6 speed or more is all you need. Must have a rear freewheel. Not a freehub and cassette.

Whats the reason your recommend 26"?

Do they still make steel frame bikes anymore? Been looking around and everything is 6061 in one form or another. Cant find any that specifically state steel dropouts anyway so if thats a must have criteria i'm pretty screwed. how about one of these?.

http://www.trekbikes.com/int/en/bikes/mountain/sport/3_series/3900_disc/
http://www.focus-bikes.com/au/en_au/bikes/bikes-2013/category/mtb-hardtail-11/subcategory/sport-13/model/highland-peak-disc-24-g-6.html
http://2011.feltracing.com/Australia/2011/Mountain/Q-Series/Q220.aspx

As I said really only for on road use. Would have to go a different kit to the one you suggested though because of the disc brakes. Something like.

http://www.ebay.com.au/itm/Premium-1000W-Hi-Speed-Electric-Bicycle-E-Bike-Hub-Motor-Conversion-Kit-/390645463157?pt=LH_DefaultDomain_2&hash=item5af448b875&_uhb=1#shId

Battery. Hundreds of choices. Only one must have criteria. It MUST be able to provide the max amperage of the controller you use. 30A for above kit. I use RC lipo from Hobbyking.com. A 12s pack of 20C or higher is perfect because the LVC of the controller is perfect at 42V. But any type pack with a MAX voltage of no more than 63V will work as long as it can supply 30A. There is an HK warehouse in AU. Order from it if you go with lipo. 12s lipo (44.4V/50.4V) will get a minimum top speed of 45kph.

Ok so I had a browse through the batteries thread. So if i want to keep weight down and also put the battery on a rear rack lipo seems the way to go as long i treat them with respect. I had a look at Hobby King and I cant seem to find A 10ah 12s pack so by saying

A 10ah 12s pack will cost from $150- $250 depending on how you configure it

You are saying get something like 4 X http://www.hobbyking.com/hobbyking/store/__8582__ZIPPY_Flightmax_5000mAh_6S1P_20C.html and group them together? am I close or not even?

Thanks again.

 

[dogman dan]

Nothing wrong with that bike that I can see in the small picture.

Steel is good, but not mandatory. Steel or alloy, you will want a good torque plate. Often for the rear, the best thing is to make your own. The thing you need on the bike is a large flat area around the dropouts to bolt it to. Fancy bikes tend to have too many holes for lightness, or funny shapes that make bolting a torque arm or torque plate on hard to do.

Your speed and power needs are easy to fill. Pretty much any direct drive motor kit will get you that speed, and you have the option of not pedaling at all up grades up to 5%. With pedaling 10% grades are ok.

The battery is where people trip up. Make sure you have enough capacity to power the controller you choose. Many of the smaller 10 ah packs are too small for the larger motors, but get sold with them in kits anyway. I tend to recommend 15 ah as the minimum size, unless you are getting higher discharge rate cells.

Mount that battery inside the frame triangle up front if possible.

Big wheels work best for pedaling, because you can select the correct gear.

Small wheels work best for hubmotors, because they are locked in the gear they are in. The rim size is the gear.

26" wheel is a compromise between 20" and 700c. In 26" bikes are plentiful and cheap on the used market, and tire selection is huge and affordable. So 26" is a good choice for utility commuter bikes.

24" might be the ideal for hubmotors, but good tires are hard to find, and bikes even harder.

 

[d8veh]

The bike you showed at the beginning looks OK apart from one thing: It has integrated brakes/gear-changers. This means that you can't use standard ebrakes. Instead you need in-line brake sensors like these:
http://www.bmsbattery.com/accessory/459-hwbs-hidden-wire-brake-sensor.html

Also throttles are hard to fit around those brakes as well. I think that the only one that will fit is a plain half-throttle (not the one with a switch and LEDs).

Full suspension bikes are more comfortable, but it makes battery installation much more complicated. You can get a strong seat-post rack, but you have to allow at least 100mm for wheel movement that means that the battery ends up much higher, which is not good for handling. If you want to mount the battery on a rack, you want it as low and far forward as possible. I'd stick with a hard-tail for a first build.

 

[wesnewell]

Whats the reason your recommend 26"?

Standard hub motor kit size.

Do they still make steel frame bikes anymore? Been looking around and everything is 6061 in one form or another. Cant find any that specifically state steel dropouts anyway so if thats a must have criteria i'm pretty screwed. how about one of these?.

Try some of the big box stores like kmart or target. Take a magnet with you and check the dropouts. Maybe something like this.
http://www.kmart.com.au/product/southern-star-66cm-%2826%29-terrain-dual-suspension-mens-bike/122406
You don't need disc brakes. Decent pads on V brakes on a 26" wheel is like huge disc brakes. First time I hit the front brake on v brakes I almost went over the handle bars. Raised my 270 lbs and rear wheel off the ground. If you can't find a bike with steel dropouts get 2 torque plates or arms. I've put almost 10,000 miles on my steel dropouts without torque plates/arms. A *properly* mounted hub motor on steel dropouts doesn't need anything else. It will be better than a crappy install using torque arms on aluminum dropouts.

You are saying get something like 4 X http://www.hobbyking.com/hobbyking/store/__8582__ZIPPY_Flightmax_5000mAh_6S1P_20C.html and group them together? am I close or not even?

Yes, and a 12s balance charger.