I'm a noob and I wanna go sensible speeds reliably

[headwind]

Hi Endless Sphere,

Preaching to the converted
I recently borrowed an e-bike and, wow, you folks sure are onto something! It is the best form of transport I have ever used, quicker and cheaper than public transport. And, around the inner city, it is actually quicker than a car. Incredible!

So now I ask for your help to get one for myself...

Usage
- maximum speed 40 km/h edit 30/3: for bursts only, cruising speed slower and with pedal assist
- range of 50km assisted (I pedal at a comfortable non-sweaty level, while the motor does the hard work. My typical consumption is 12 Whr/km) edit 30/3: my regular commute is a 25km round trip, but I'd like more range for other trips
- road usage and some gravel bike paths, but no off-road mud-bashing
- good resistance against punctures and bent rims (I have been getting a lot of flats on my road bike which has been very frustrating)
- wet weather friendly
- battery needs to be charged separate to the bike, since I don't have a powerpoint where the bike is stored
- doesn't look like an e-bike to the average driver

Many thanks to kabbage for the "test rides" of his setup, it is a wonderful machine. Some changes I'd like for my e-bike are less tail-heavy handling, faster when human powered and ease of battery removal. I think lighter batteries mounted within the triangle will go a long way regarding the first two points.

Current plans
edit 30/3: Base bike will be a lightweight hybrid or mountain bike. Old text below:
Mountain bikes generally don't float my boat (extra weight, also I prefer the feel without suspension). Ideally, I'd convert a flat bar road bike like my Apollo Fiamme, but for starters the wide tyres won't fit. So I'm leaning towards a hybrid frame, unless I can find a lightweight and suspension-less MTB for cheap.


As for the e-bits, I really like the BPM 36V500W 11T motor (could possibly downsize to the 250W but the 500W isn't too heavy and leaves headroom if I get the power bug in future) and 25 amp C7225-NC controller's performance kabbage uses, so I'll stick with that. Also, a hand throttle and Cycle Analyst like his are part of the plan.

The battery is still undecided, aside from going 48v, mounting it as low as possible in the triangle and having it easily removable (for charging and to take it with me when I park somewhere dodgy). 12Ah is plenty for me, I could even come down a bit from that. LiPo is tempting, if I'm brave enough. Actually, I've just had a crazy idea of having half the capacity and carrying a second battery when I need more range. This also makes charging easier, I just swap in the other battery so I'm not waiting for it to recharge. This means that the extra weight of LiFePo4 isn't a problem, so I'm quite excited by this idea.

To not look like an e-bike, I'd like all the electronics tucked away in non-descript weatherproof bags/containers.

For packaging and simplicity reasons, I'm thinking of sticking with rim brakes. They would be upgraded with Kool Stop pads and, if that's not enough, Avid SD7 calipers.

The Mavic downhill rear wheel and Schwalbe Marathon combo on kabbage's setup is wonderfully tough. Possibly overkill, but I'd prefer to err on this side than be dealing with punctures etc. Although if they came in narrower widths, I'd be interested, because it'd give me more options in choice of frame.

For the gearing, 3 ratios on the front chainring and locking/removing the rear cassette has worked fine. Just in case it affects the conversion, I should mention that I'm planning on 1x side pannier bag.

I'm reasonably handy with tools (I do occasional maintenance on my bike, and regularly work on my old car), but copying a proven recipe on here would make things a lot easier. So if you can think of any build threads with similar goals, it would be much appreciated if you could post the link.

And any thoughts on my plans would be much appreciated, please.

First step- get the bike for the conversion
From what I've read here, I should watch out for rear dropout strength. How do I check this on potential purchases?
Will torque arms work with my plans? How do I check the bike is suited to adding torque arms?
What else should I look for on a hybrid bike that will be converted?
I've noticed that most hybrid/road e-bikes on here use front hubs. Why is this?

Many thanks,
Simon

 

[pjgold]

I'm a noob and I wanted pretty much the same things as you do.
Reliable and easy.
http://www.bhbikes.com/web/en/easy-motion-ebikes/road/neo-road/neo-race.html or http://www.bhbikes.com/web/en/easy-motion-ebikes/cross/neo-cross/neo-cross.html
I went for the Cross

 

[el_walto]

I'd suggest getting the mountain bike and 2.5 wide tires if you don't want suspension. Also you can then get disc brakes and not deal with crappy rims.

You will only need a 48V 15Ah battery pack (17lb) because you are efficient 12wh/km, but I'd go for 20Ah(22lb) if I were you.

I <3 the geared MAC 10T @ 48V, it's really solid in a DM24 rim. BUT if you don't have steep hills to deal with, you really should go direct drive, as they are a bit more efficient, and less noisy for a flat environment.

The rear MAC motor is nice and small and can not really be seen if you put a rear rack and large bags on.

 

[MadRhino]

Don't build a road bike with a hub motor. This is my advice.

If I wanted to build a on a road bike frame, I would use a friction drive.
It is simple, light weight, can be removed quickly, and can achieve pretty good performance without any alterations to drive train or dropouts.

 

[-dg]

I'm planning something with similar design goals and most of what you suggest looks reasonable. A few observations based on my research and building a bike with a front Bafang SWXK:

- A rear Bafang BPM or CST should be more than enough motor unless you are heavy and have lots of steep hills They also seem to be readily available, have parts available, and not much is said against them. I'm undecided which, the CST is apparently better made but there are a lot of BPMs out there and they are amazingly inexpensive. I don't know that it matters.

- Un-suspended 80's and 90's steel mountain bikes are good candidates as they are strong, ride decently, have roomy triangles, rack eyes, practical running gear and can fit large tires and fenders. Around here very nice upper-mid range bikes in almost new condition can be had for almost nothing. I just picked up a 1991 Trek 950 (around $700 new) that needed only a new chain, cable inners and a good wash for $80. Road bikes from that period are expensive around here as they are fixie conversion candidates or are "vintage", whereas last years mountain bike is merely "obsolete".

- I'm budgeting 15 wh per km as I'm heavy, it's hilly here, and I will probably go too fast for economy. That said, I could probably eek out 12 wh/km with some self discipline.

- I've decided to use RC LiPo, the size and modularity and price advantages are decisive. It should be no problem to fit 15 or 20ah 12s in the triangle, either in a frame bag or some sort of box. I'm using server power supplies and a Hyperion 1420 to charge.

The most difficult parts I found building my first e-bike are the crappy connectors that come with the throttles and controllers and getting all the wiring tidy and inconspicuous. I'm still looking for a clean reliable and weatherproof wiring solution.

 

[chas58]

Simon,

I had the same ideas of doing two small 36V8ah batteries. One for short rides, and bringing a spare for long rides. Or, they could be wired in parallel for 36V with twice the amp capability.

How big of a tire do you want? It takes 35mm, what is your target? You can go bigger than the stock tire range, unless you are worried about clearance with a fender. Size of tire will help determine size of the rim you order.

I am thinking about the BPM 350V11T motor for one of my bilds. How do you know if they are selling you the 11T?

 

[chas58]

Don't build a road bike with a hub motor. This is my advice.

If I wanted to build a on a road bike frame, I would use a friction drive.
It is simple, light weight, can be removed quickly, and can achieve pretty good performance without any alterations to drive train or dropouts.

This is a good possibility for me, especially if I can not get a motor for a 120mm rear drop out which my bike has). Where can I find more about how to do this. Plenty of info on Cutes and BPMs here, but how do I get started on designing and building a friction drive???

 

[MadRhino]

I am not into this kind of build, so not much help for you but they are pretty small and simple.
I believe Kepler and Adrian-sm are the guys to give you advice about it.

 

[spinningmagnets]

I have two friction drives, I could sell you one with no battery or charger for $150. I'd say its about $200 for the parts, and you'll be getting my work for free. It comes with an 18V-28V Castle Creations controller, and a servotester with a dial on the shaft as a throttle. It works quite well, but it works best with a fat square-profile beach-cruiser tire (which I can include).

The seat-post and seat are not included, but the seat-post adapter-sleeve and stem-as-a-mount is included. It will do 20-MPH on 6S / 22V, and around 25-MPH on 8S / 28V. If you want to use 10S/37V or 12S/44V for a higher speed, you would have to buy a different controller.

A Kepler and Adrians drive will definitely be smaller and lighter than this one, but I believe this one can take more heat than them.

 

[dogman dan]

You'll use more power than 12 ah, on a 50k ride at 40kph. Maybe not right away, but it will creep up on ya even though you are quite a pedaler.

48v 20 ah of lifepo4 won't fit in the triangle. But a 48v 15 ah pingbattery lifepo4 should. You might want to go with even smaller if most rides are only 10-15 k though. 12s , "44v" lipo in 10 ah size is a very convenient to carry battery. A second one in a knapsack or rear rack is quite possible for longer rides. Don't buy a small battery in lifepo4 though, it won't be made for 20 amps.

Lipo can be a pita if you charge twice a day though. Much depends on the use pattern. If you really go 50k daily, I'd recommend the ping lifepo4. Then you can plug in, and go to sleep, or charge at work safer.

26 inch hybrid might be better for an ebike. Able to run on nicer tires. Even fat cruiser tires. Forget about it still feeling like a road bike if you build on a road bike frame. It won't. Tie 4 gallon jugs full of water to your road bike. Does it still feel like a road bike? Hell no.

But buy that friction drive, and you get to come pretty close to feeling the same.

 

[footloose]

2 cents from relative noob.
Frequent reader of endless-sphere for last year, and I've built two e-bikes.

First is friction drive -- Adrian's Commuter Boooster setup. Love it, it rocks. Lightweight bike... mid-80s Raleigh road bike. Setup/weight is minimalist in the extreme. On level paved road? ++++ On hills? Not quite so much. On steep hills? Pedal, friends, pedal, and sweat.

Second is rear MAC hub from cell_man, with 48v/12ah battery pack. Built on a 1982 Specialized StumpJumper frame. I live in the hills midway between San Francisco and San Jose. This setup is great on hills... hauls groceries... fast... ample range... will lift front wheel off the ground if I grab throttle (a virtue?).

I love the friction drive, but it's a thoroughbred. I love the MAC setup, and it's a workhorse.

(Next bike may be an exotic... friction drive on a Bike Friday Tikit?)

 

[spinningmagnets]

From reading (I've never owned one of these)...my "go to" suggestion for the majority of new E-bikers for their first (I believe most people will end up with two ebikes eventually), is a cell_man 10T using 48V and limited to 25A. Many happy customers using that.

http://em3ev.com/store/index.php?route=product/product&path=36&product_id=55

 

[headwind]

Thanks everyone for the replies.

http://www.bhbikes.com/web/en/easy-motion-ebikes/cross/neo-cross/neo-cross.html

After initially wanting something off-the-shelf like this, I've decided I want to build it myself. Mainly so that when something breaks, it is easier for me to troubleshoot it if I have put it together myself.

I'd suggest getting the mountain bike and 2.5 wide tires if you don't want suspension.

Yeah, although I prefer the lighter and simpler hybrids, a mountain bike might be better suited. Hopefully I can find something not too heavy.

If I wanted to build a on a road bike frame, I would use a friction drive.

I really like the acceleration from standstill of the hub motor, so friction drive isn't for me. Therefore I've dropped the road bike idea.

I had the same ideas of doing two small 36V8ah batteries. One for short rides, and bringing a spare for long rides. Or, they could be wired in parallel for 36V with twice the amp capability.

Great minds think alike! My plan is for 48V though. I won't worry about wiring them in parallel, I'll just swap the other one from my backpack when needed.

How big of a tire do you want? It takes 35mm, what is your target? You can go bigger than the stock tire range, unless you are worried about clearance with a fender.

The bike won't be running fenders, so the only issue is clearance on the frame if I go for a hybrid bike. Sorry, I don't understand what you mean by "it takes 35mm"?

You'll use more power than 12 ah, on a 50k ride at 40kph. Maybe not right away, but it will creep up on ya even though you are quite a pedaler.

40 km/h is the occasional maximum speed, not cruising speed. I have ridden kabbage's e-bike for a few trips and 12 Whr/km is about where I'm at. Hopefully by limiting my capacity, it'll stop me from getting too lazy with the pedalling!

12s , "44v" lipo in 10 ah size is a very convenient to carry battery. A second one in a knapsack or rear rack is quite possible for longer rides. Don't buy a small battery in lifepo4 though, it won't be made for 20 amps.

I'm hoping to stick with LiFePo4 to keep things simple, and have it fit in the frame by reducing capacity. But the smaller LiPo is tempting, thanks for the suggestion.

When you say "it won't be made for 20 amps", do you mean Ah or peak current?

If you really go 50k daily

50km is the worst case occasional trip. Work and back is 25km.

Forget about it still feeling like a road bike if you build on a road bike frame. It won't. Tie 4 gallon jugs full of water to your road bike. Does it still feel like a road bike?

Hahaha. Point taken, I'm looking into hybrids now instead, or a lighweight MTB (Kepplar's would be perfect 8) , but my budget is less than half of his, so mine will have to be heavier)

cell_man 10T using 48V and limited to 25A

Thanks for the suggestion. I am looking for a clutched setup, though, to make me less reliant on the motor.

 

[Popstar]

cell_man 10T using 48V and limited to 25A

Thanks for the suggestion. I am looking for a clutched setup, though, to make me less reliant on the motor.

FYI, Mac is a geared hub hub motor that freewheels.

I am moving to the MAC 10T soon, after getting my ebike feet wet last summer with cellman's geared mxus e-assist [which sadly he stopped carrying. He says he will be offering a new mini-geared option soon] on a folding dahon.

-Popstar

 

[Eskimo]

Personally i love the silence of a DD motor. It keeps the illusion of cycling pretty much intact sound-wise. While driving slowly through downtown shopping streets it"s extremely stealthy, you just glide forward like a ghost. I think i made the right choice, though i know these spokes or hall sensors can blow sometime, allready ordered a set of better spokes. At the moment they sound evenly tightened, i think guy who sells these here checks and trues these before sending. I think 500W DD on 48V hits that 40 km/h with light pedaling, approx. Pot holes on that speed start to appear way too fast without suspension. Just watched both of them Youtube documents about Justin"s trans-continental trip and that technical video too. Very informative. Charging on the road in Canada seems pretty easy. Here i am thinking a day trip to a town called Porvoo, and i have no bloody idea where i could charge there. They have a tourist byroo but i bet few euros they have not heard a question about bicycle charging too often Something like McDonalds might work but my charging kit is just too noisy to be used in a coffee place etc. Those sockets that are used to warm car"s engines during the winter are locked and timed usually. My choice was lipos because i have allready played with them a lot since 2004 because of RC stuff. I am happy with 100 good full cycles out of them. I think i don"t have a time to ride more than 200 times per year, summer is short, and new set of lipos every year is not that expensive investment really.

 

[-dg]

2 cents from relative noob.
Second is rear MAC hub from cell_man, with 48v/12ah battery pack. Built on a 1982 Specialized StumpJumper frame. I live in the hills midway between San Francisco and San Jose. This setup is great on hills... hauls groceries... fast... ample range... will lift front wheel off the ground if I grab throttle (a virtue?).
...
(Next bike may be an exotic... friction drive on a Bike Friday Tikit?)

I'm just across the bay from you. My first build was a Bafang SWXK front for my wife's mixte and the second is likely to be BPM rear or maybe the MAC in a 91 Trek 950 (similar to your Stumpjumper). How noisy is the MAC?

I have a Tikit that I'm probably going to sell, PM me if you have not got yours yet. I like it, but don't use it often these days due to change of work location. If I were electrifying it I'd use a Cute100 or Bafang SWXU in front with the fast wind. The 16" wheels work out very favorably for hub motors.

 

[John in CR]

"I'm a noob and I wanna go sensible speeds reliably"

One person's sensible is another's insane. With drivers commonly distracted by texting, spilling their coffee, checking out some hottie on the other side of the road, looking at their GPS that has caused them to lose all sense of direction, or any other stupid thing drivers do, I believe it's insane to trust every passing car not to run over you. To me it's only "sensible" to match or exceed traffic speeds, so your ebike plan is too slow.

 

[dogman dan]

Sounds to me like you rode enough to know how to not let them hit you.

Mac 10 t for the win. Run it on a 48v 15 ah lifepo4 from pingbattery.com. It's got an internal freewheel, so it will coast well if you want to ride pulse and glide.

Quick battery lesson. I did mean amps, from the controller. Get a 20 or 25 amps controller at most. To use a typical lifepo4 or limn battery at a reasonable rate, you want to discharge it at 1c to 1.5c continuous discharge rate to keep from murdering your battery. So if you got an 8 amp hour battery, 1c discharge rate is only 8 amps. So a 20 amps controller would be a bit hard on a battery able to discharge 12 amps at 1.5c.

Other batteries can do higher c rates, such as A123 lifepo4. Since you will at times want to go longer distances, getting a 15 ah battery won't be that big a burden. 48v 15 ah ping carries pretty nice, and will fit into the triangle space of many bikes.

A hybrid is basically a 26" mtb with a taller handlebar on it, and road tread tires. With a motor, there is NO advantage to a 27" tire. So don't limit your frame search to just hybrids. Entry level MTB's similar to the trek 820 work great. Just put bmx handlebars on them, change tires, and viola, hybrid bike with front shocks.

It will be heavy, so forget pedaling it unpowered much. It works like this, set throttle to a speed, say 32kph, then pedal up another 2-3 kph . You still get great exercise and still extend your battery range. But if you must, it can still be pedaled unpowered if the battery is dead. Pedaling down hill still works fine of course.

 

[Kabbage]

Thanks everyone for the replies.

I had the same ideas of doing two small 36V8ah batteries. One for short rides, and bringing a spare for long rides. Or, they could be wired in parallel for 36V with twice the amp capability.

Great minds think alike! My plan is for 48V though. I won't worry about wiring them in parallel, I'll just swap the other one from my backpack when needed.
.

Unfortunately, your idea to carry half the battery capacity and 'switch out' doesn't work; as dog man has pointed out, battery capacity (in Ah) doesn't just limit how far you can go, it also limits how much current you can put out at any one time.

So if you want the torque at 'take off', you need to be able to deliver 25A+, and to do that you need at least 12Ah at 2C (which can deliver 2xCapacity in instantaneous current) or 15Ah at 1.5C.

My headway battery can supposedly deliver up to 5C in bursts, and sustain up to 2-3C; hence my 25A controller. Of course you can always 'ask for more' from your battery, and this will result in it heating up more and greatly reducing the number of cycles you will get out of it.

This is why people go for LiPo, it'll do 5C easy, and many do 10C continuous and 30-50C in short bursts. That means they can get away with 'standard' 5Ah packs and still deliver 25A... But the reason it can chuck out so much current is that the chemistry is reactive as hell; hence all the fires when things don't go as planned...

 

[headwind]

FYI, Mac is a geared hub hub motor that freewheels.

Whoops! Thanks for clearing up my mistake.

Quick battery lesson.
<snip>

Ahhh, thanks for the explanation. Now I understand that swapping between smaller LiFePo4 batteries won't work. The LiPo option you mentioned earlier is now more appealing, I'll look into this more.

A hybrid is basically a 26" mtb with a taller handlebar on it, and road tread tires. With a motor, there is NO advantage to a 27" tire. So don't limit your frame search to just hybrids. Entry level MTB's similar to the trek 820 work great. Just put bmx handlebars on them, change tires, and viola, hybrid bike with front shocks.

Oh, I'd incorrectly assumed that a hybrid frame would be significantly lighter than a MTB.

Unfortunately, your idea to carry half the battery capacity and 'switch out' doesn't work; as dog man has pointed out, battery capacity (in Ah) doesn't just limit how far you can go, it also limits how much current you can put out at any one time.

...

This is why people go for LiPo, it'll do 5C easy

Maybe I will end up "playing with fire" then! I'm leaning towards LiPo at the moment, more research is needed though.

Clearly I have much to learn. Thanks for everyone's patience with my noob questions.

 

[dogman dan]

Oh, I'm sure if you pay enough for it, a hybrid frame will be very light. So will a mtb. Some hybrids do have differences, such as pedal located further forward. Mostly they just have fenders or racks an mtb lacks. Some are 700c wheels, but again, once motorized, no advantage to that. Some have really good racks, like a double dutch. But by that point I'm calling it a cargo bike rather than a hybrid.

Take a decent mtb, put street tread on it, and you got a hybrid more or less. Not saying don't buy a hybrid at all, just saying don't limit your choices so much either. You'll find that 15 pounds of hubmotor and 15 pounds of battery will make the thing heavy. So a bike that weighs 5 pounds more stops mattering so much. Hit the throttle, and it sill goes fast.

Sometimes weight is a big consideration. Maybe you have to carry the bike up two stories of stairs. Then you might choose for less power and speed with a smaller motor, then carry the battery up in a second trip up the stairs, or backpack the battery.

Here is an example of an inexpensive steel mtb, that's ideal for a rear motor. Skinny tires and a riser handlebar, and presto, it's a hybrid.

 

[spinningmagnets]

It's my understanding that that even though there are a great deal of similarities between "some" hardtail MTBs and "some" hybrids, the main difference is that the fat tires are good for occasional off-road use and streets with frequent and sometimes unavoidable potholes (like where I live). The smaller tires on hybrids have less rolling resistance, and even more-so if they are run at a higher pressure. That is the reason for having the front suspension rather than having a lighter (but similar) bike with no front suspension.

If your riding posture is leaning forward for less wind resistance, front suspension becomes more important to reduce unexpected shocks to your wrists (especially if you're old like me). Hybrids are for a short-to-medium range commuter or occasional exercise on reasonably smooth streets. Lycras sometimes sneer at "hybrids" because they are heavier (front suspension), but a lot of hybrids are sold to non-lycras.

If you ride upright (beach-cruiser posture), or semi-recumbent (my favorite), with fat tires, front suspension becomes almost unimportant at average speeds...but with this posture, a rear suspension can provide a big improvement to your comfort. And if not rear-sus, then at least Thudbuster (pricey at $120-ish, but worth it on a hardtail commuter).

 

[andyshirley]

Hybrids also have the benefit of more teeth on the chain ring. I have a mountain bike and changed from a 44 teeth to a 48. Coupled with an 11-28 freewheel. I can now peddle to around 30mph on a decline. So in my opinion if you get a mountain bike you will end up swapping out the gearing, whereas with a hybrid it will be somewhere in between mountain and road gearing, stock. Something else for you to think about.

 

[chas58]

Mac 10 t for the win. Run it on a 48v 15 ah lifepo4 from pingbattery.com. It's got an internal freewheel, so it will coast well if you want to ride pulse and glide.

Quick battery lesson. I did mean amps, from the controller. Get a 20 or 25 amps controller at most. To use a typical lifepo4 or limn battery at a reasonable rate, you want to discharge it at 1c to 1.5c continuous discharge rate to keep from murdering your battery. So if you got an 8 amp hour battery, 1c discharge rate is only 8 amps. So a 20 amps controller would be a bit hard on a battery able to discharge 12 amps at 1.5c.

Other batteries can do higher c rates, such as A123 lifepo4. Since you will at times want to go longer distances, getting a 15 ah battery won't be that big a burden. 48v 15 ah ping carries pretty nice, and will fit into the triangle space of many bikes.

Thanks so much for the battery lesson!

I was wondering why people kept saying a 15amp 8ah battery (like BMS battery sells) would not be strong enough. According to what you are saying, that battery will struggle to put out much more than 8-12 amps while a 15ah should be happy putting out 20amps. I have no idea what the C rate is for the BMS batteries is.

I guess if you had two 8Ah batteries in parallel, you would still have the current of the 15Ah battery, but the ability to travel light with less power if using only one of the 36v8Ah batteries.

P.S. I’m thinking of a mac 8t @ 36V or a mac 10T at 48V

 

[headwind]

The shopping has started! Thanks for the schooling on mountain bikes and hybrids, I picked up a barely-used hybrid last night: http://www.giant-bicycles.com/en-us/bikes/model/cypress.dx/9019/48868/
Very comfy, not too heavy. I'm a bit embarrased to own a Giant (like every man and his dog), but it was a great deal. Hopefully it won't protest too much as the electric parts get added!