Another newbie to ebikes - planning my first

[highlander]

I am researching my way towards becoming an ebiker. I have a very basic understanding of ebikes after doing some reading this weekend. I wanted to discuss my ideas here - I'm sure this type of topic comes up all the time, so if mine is not unique, just point me where I can read up.

Background - I would like a bike to ride short distances around town and show up not looking like I just ran a marathon. I would enjoy the project of building/assembling a conversion kit. Top speed is not a big concern, 15-20 mph should be fine, anything higher is a bonus. My main motivation for an ebike is to help me climb the occasional hills that are occasionally steep. Range is not a big deal either, typical ranges that I have seen (~20 mi) would be plenty for me. I weigh 150 lbs. I would like to come in under $1000. The tricky part is that includes the cost of a bicycle, which will vary a lot, so lets say $6-800 for the conversion portion.

Here is what I am thinking so far. I am obviously not set on any of these points and welcome other's thoughts.

Bike
steel framed mountain bike with front suspension
26" tires - seems simplest for conversion kits
Brakes - here is where I'm not sure. I know disc are preferred, but are v-style brakes acceptable?

Motor
Rear Hub drive - hub over mid drive for cost consideration. Rear over front for safety + pedal assist function
Geared over direct drive - I'm thinking this will be better for climbing hills. If I am already at speed, maybe DD is ok? Also, I think I would like the pedal assist rather than throttle drive or whatever the correct name is.

Controller
A little fuzzy here. I'm not trying to spec out anything special, but seems like this is the deciding point for pedal assist functionality. I'll probably end up buying packaged with the motor, but do only the sensored/smart systems offer the assist capability? How does this impact cost?

Battery
Obviously depends on the system I get, but I've read enough to stay away from Chinese products. After picking a motor, I'll get a compatible battery that meets my range requirements.

I think I covered it all, but might have left out some crucial info. Any input or discussion points are welcome. Thanks!

 

[2old]

+1 on ypedal; he's helpful, courteous and accessible; procured an excellent kit for a friend from him
another possibility is YESCOM kit (cheaper @ accesseries, go to ebay and put 48V, 1000w into browser); heavy DD, but excellent kit for about $240
with Luna Cycle battery, you'll easily stay in price range

 

[motomech]

I am researching my way towards becoming an ebiker. I have a very basic understanding of ebikes after doing some reading this weekend. I wanted to discuss my ideas here - I'm sure this type of topic comes up all the time, so if mine is not unique, just point me where I can read up.

Background - I would like a bike to ride short distances around town and show up not looking like I just ran a marathon. I would enjoy the project of building/assembling a conversion kit. Top speed is not a big concern, 15-20 mph should be fine, anything higher is a bonus. My main motivation for an ebike is to help me climb the occasional hills that are occasionally steep. Range is not a big deal either, typical ranges that I have seen (~20 mi) would be plenty for me. I weigh 150 lbs. I would like to come in under $1000. The tricky part is that includes the cost of a bicycle, which will vary a lot, so lets say $6-800 for the conversion portion.

Here is what I am thinking so far. I am obviously not set on any of these points and welcome other's thoughts.

Bike
steel framed mountain bike with front suspension
26" tires - seems simplest for conversion kits
Brakes - here is where I'm not sure. I know disc are preferred, but are v-style brakes acceptable?

Motor
Rear Hub drive - hub over mid drive for cost consideration. Rear over front for safety + pedal assist function
Geared over direct drive - I'm thinking this will be better for climbing hills. If I am already at speed, maybe DD is ok? Also, I think I would like the pedal assist rather than throttle drive or whatever the correct name is.

Controller
A little fuzzy here. I'm not trying to spec out anything special, but seems like this is the deciding point for pedal assist functionality. I'll probably end up buying packaged with the motor, but do only the sensored/smart systems offer the assist capability? How does this impact cost?

Battery
Obviously depends on the system I get, but I've read enough to stay away from Chinese products. After picking a motor, I'll get a compatible battery that meets my range requirements.

I think I covered it all, but might have left out some crucial info. Any input or discussion points are welcome. Thanks!

It sounds like you are going to use an Ebike much like I do. Relaxed, lower speeds, and in most ways, just like a reg. bicycle.
Without needing the speed to mix it up in traffic, allows you to focus on the other criteria like, ease of installation, stealth, quiteness and reliablity.
All that says geared mini motor to my way of thinking.

Bike
steel framed mountain bike with front suspension
26" tires - seems simplest for conversion kits
Brakes - here is where I'm not sure. I know disc are preferred, but are v-style brakes acceptable?

Start searching Craigslist for a older quality mountain bike. Alum. or steel, it doesn't matter for your build. A disc on the frt. at least and a big space in the triangle is what you are looking for. Used MX bikes can often be a great deal because many folks buy one, take it out once, find out how much work it is and park it.

Motor
Rear Hub drive - hub over mid drive for cost consideration. Rear over front for safety + pedal assist function
Geared over direct drive - I'm thinking this will be better for climbing hills. If I am already at speed, maybe DD is ok? Also, I think I would like the pedal assist rather than throttle drive or whatever the correct name is.

Since you are light and your speed requirement is modest, you can use a sm. min-motor that is geared well enough for moderate hills. That is, if they are not blocks long and steep enough that you would labor walking up one. If you can get a run at your steepest hill and it's less than a 1/4 long, a mini probably will be fine.

Consider this motor/wheel ASM;
https://bmsbattery.com/ebike-kit/617-q100c-cst-36v350w-rear-driving-e-bike-motor-wheel-ebike-kit.html
Disreguard the big pic, it's the little blk. motor and it will come with a pre-built wheel.
It's a CST model, which means that it will accept a cassette from you donor bike, an important consideration.
You would specify the "201" low speed motor to help with hills, but that with a 36V battery is a little slow, 17 to 18 Mph. To get the speed up 19 to 21 Mph, a 48 V battery would be the choice.(this is why the complete kit with 36V battery is not prefered).
Add this battery with intergated controller;
https://bmsbattery.com/ebike-battery/774-48v116ah-case-08-bottle-panasonic-battery-pack-battery.html
for ease of installation, neatness and for you, a degree of water resistance(Lot's of rain where you are at.).
Since this is a low-powered system, PAS will be very smooth and a pleasure to use and you will have a nice bit of range from the batt., over 20 miles.
If this is a Ebike conversion kit that you might like to use, we can go into specifics later.
Add about $150 for shipping.
You can also search here with key-words Q100, Cute, etc. or search back thru my posts

 

[wesnewell]

Take your pick. If you have rear disc brakes, make sure you get one that is compatible.
http://www.ebay.com/sch/i.html?_from=R40&_sacat=0&_nkw=48v1000w%20rear&LH_PrefLoc=1&rt=nc&LH_FS=1

 

[highlander]

Thanks for the input guys. I will keep doing some research and hope to get started in the coming weeks!

 

[Eteck]

As someone who recently went through all this, here is what stood out about your post:

typical ranges that I have seen (~20 mi) would be plenty for me. I weigh 150 lbs]

This is actually quite a bit of range unless you have a $1000 Lithium battery budget. For more modest outlays
expect maybe ~10 mi.

are v-style brakes acceptable?

20mph or less the normal bike brakes will be fine.

Geared over direct drive - I'm thinking this will be better for climbing hills. If I am already at speed, maybe DD is ok?

DD is simple, no gears to wear out. I think some geared hubs can be more efficient at a specific intended cruising speed. Virtually all
the inexpensive <$250 kits are DD.

Controller I'll probably end up buying packaged with the motor

That's easiest for a newbie.

Battery Obviously depends on the system I get

If you can make do with slightly less than 20mph it is cheaper lighter and easier to go with a 36V (350-500W) rather than a 48V (1000w) system.

I would like to come in under $1000

If you are careful and can do some of the work yourself, such as battery mounting or other needed bike mods, you can build a really nice
Ebike in this price range.

 

[highlander]

So I like the suggestions of the smaller motors. Let me make sure I am applying these concepts correctly.

Comparing a 36V 500W motor to a 48V 500W motor - the 48V will translate to a higher top speed. But since they have the same wattage, the trade-off is less Amps - which translates to weaker acceleration (?).

I haven't shopped for batteries yet, but I assume the 48V motor will require a bigger/more expensive battery. Any other considerations?

Bafang or Q100 systems are the most intriguing right now. They seem equivalent to me, any preferences from others?

 

[wesnewell]

The is very little difference in cost between a 500W kit and a 1000W kit. Don't waste your time on a 500W motor. Even a 48V 500W kit will not satisfy many people. 2 weeks after buying a 48V 500W kit I bought a 48V 1000W kit. Should have started with it. Much better performance from the 1000W kit.
As for the battery pack. I've been using nothing but rc lipo for the last 5 years and would not buy anything else at this time. it's the cheapest most powerful setup you can get. Put a 44.4V 12s pack on the 1000W kit and you can expect a top speed of ~28 mph . A 12s pack on a 48V 500W kit will get you ~23mph and less acceleration. A 5ah 12s 20C rc lipo pack will cost <$100. If you need more range, it's a simple matter of plugging another 12s pack in parallel.

 

[Chalo]

Put a 44.4V 12s pack on the 1000W kit and you can expect a top speed of ~28 mph . A 12s pack on a 48V 500W kit will get you ~23mph and less acceleration.

And your bike becomes an even heavier pig with a whole lot less range. Since the OP already said he only wants 20mph, why shouldn't he go with something safer, lighter, cheaper, and legal?

 

[Eteck]

Comparing a 36V 500W motor to a 48V 500W motor - the 48V will translate to a higher top speed.

Yes. But it may not be a different "motor". In real kits for sale, the hub may be the exact same hub, only the controller is different.

But since they have the same wattage, the trade-off is less Amps - which translates to weaker acceleration (?).

The key thing is that "higher top speed" translates to "more power used" which translates to "less range" or "more battery lbs and $$$ ".

I haven't shopped for batteries yet, but I assume the 48V motor will require a bigger/more expensive battery.

Absolutely.

Any other considerations?

Since most hubs will work fine with a lower voltage with reduced power and speed, one thing you might try, if you are not sure how much power
you need, is getting a 48V kit and then buy an extra 36V controller to start with. These small 36V controllers are inexpensive $15 - $25 and
you can try the setup at 36V. If that's not enough power/speed you can upgrade to 48V, since you'll already have a controller and hub you know
is rated for the higher power.

 

[Eteck]

Mongoose 26" Ledge 2.1 mtb bike $99, yescomusa.com 48V 1000W rear hub kit $276, Hua Tong 72V 40A controller $35, 10ah 24s lipo $275=40+mph, range=45 miles @20mph. 20K miles and still going strong.

So you are going with less AH but higher voltage then. 24S x 3.7V = ~90V which at 10AH translates to .9KWH of stored energy assuming 100% discharge of the battery.
To achieve a 45 mi range you need 2.25 hours of battery run time that will propel the bike at an even 20mph, which works out to a max of about 400W of drain on the battery
allowed throughout the 2hrs and 15 minutes.

The range you are claiming seems a bit high too me but, admittedly, I haven't tried your setup.

So your saying the Hua Tong 72V 40A controller works good at 90V (actually 100.8V since the batteries start at 4.2V) ?

 

[wesnewell]

Put a 44.4V 12s pack on the 1000W kit and you can expect a top speed of ~28 mph . A 12s pack on a 48V 500W kit will get you ~23mph and less acceleration.

And your bike becomes an even heavier pig with a whole lot less range. Since the OP already said he only wants 20mph, why shouldn't he go with something safer, lighter, cheaper, and legal?

The difference in weight is about 2 pounds of copper. And neither will be legal since they both exceed 20mph. And since 48V 1000W kits are more common, one can actually buy them for less than a 500W kit. There will be no range difference at ridden at the asme speed. In fact the 1000W kit may have better range than the 500W kit because it will be more effcient under heavier loads.

 

[d8veh]

So I like the suggestions of the smaller motors. Let me make sure I am applying these concepts correctly.

Comparing a 36V 500W motor to a 48V 500W motor - the 48V will translate to a higher top speed. But since they have the same wattage, the trade-off is less Amps - which translates to weaker acceleration (?).

I haven't shopped for batteries yet, but I assume the 48V motor will require a bigger/more expensive battery. Any other considerations?

Bafang or Q100 systems are the most intriguing right now. They seem equivalent to me, any preferences from others?

A lot of people coming in from different angles. The direct drive motors are fairly big and heavy. they also tend to need bigger batteries and controllers, which adds more weight. The end result is something that's pretty heavy and not easy to pedal without power, so a bit more like an electric motorcycle. The smaller geared motors make a lot of torque. Don't worry about gears wearing out, that was a thing from the distant past. Even if they did wear out, they're cheap and easy to replace. If you want your vehicle to be more like a bicycle, but with enough oomph to get you past 20mph, a middle-sized geared motor would do the job nicely. That means that you can use a smaller, lighter battery, which improves the handling of the bike a lot. The downtube mounted batteries are pretty good. I would go with a 48v battery and a motor that will spin up to about 270 rpm at 48v if you want a modal speed of 20 mph.

Most hub-motors have the thread for freewheel gears and some have the spline for a cassette. I would always get a cassette motor because it's easy to get an 11 tooth top gear for relaxed pedalling. A cheap donor bike will probably have free--wheel gears with 14T top gear, which is too low for an electric bike. There's workarounds to get the correct gearing with free-wheel hub-motors, but they bring a lot of complication to your build. It's no problem if you don't want to pedal, of course.

Motors come in different speed versions, so you don't need to over-volt to get a higher speed. Whatever motor you get, make sure that you get one with the correct maximum speed (RPM). 260 RPM is about 22 mph in a 26" wheel. The speed of the motor has a big effect on efficiency, so it's important that you get one that's not too fast for the speed you'll actually ride. Maximum efficiency comes at about 60 % to 75% of maximum speed. When you run a motor above it's nominal voltage, it will max out at a proportionally higher speed, produce proportionally more torque, but it moves the efficient range higher in rpm (decreases efficiency at lower rpm), and you have to consider how much power the motor can take.

If you don't already have a bike, get one with disc brakes. Rim brakes are great on 7kg road bikes, but have no place on a 25kg or more electric bike. Cheap bikes normally come with cable disk brakes, which can be crappy too, but you can upgrade the front one to a branded hydraulic one for $50 or less, which makes a massive difference to your braking. They don't need any adjustment either. Just put one on and use it. Simple as that.

 

[wesnewell]

Motors don't care what size the batteries are because they get their power from the controller. Only the controller cares about the battery. You need a battery capable of output compared to the max amp draw of the controller.
Some people in the US might be happy with a 48V 500W kit, but not a 36V 500W kit that won't even reach 20 mph except with no load on it. 260rpm will only get you 20.11 mph unloaded speed. Actual speed when riding will be considerably less with a rider, especially going up any hill.
If you don't understand wattage ratings,read this.
https://endless-sphere.com/forums/viewtopic.php?f=2&t=74403
And you don't need disc brakes. In fact, rim brakes will have more stopping power than most common disc brakes. Rim brakes are just disc brakes on a big disc. Think about it. You do need decent pads though. Not the small ones that come stock on most cheap bikes.
I've got about 20K miles on ebikes I've built in the last 5 years with motors ranging from 500W to 3000W.

 

[Chalo]

Put a 44.4V 12s pack on the 1000W kit and you can expect a top speed of ~28 mph . A 12s pack on a 48V 500W kit will get you ~23mph and less acceleration.

And your bike becomes an even heavier pig with a whole lot less range. Since the OP already said he only wants 20mph, why shouldn't he go with something safer, lighter, cheaper, and legal?

The difference in weight is about 2 pounds of copper. And neither will be legal since they both exceed 20mph. And since 48V 1000W kits are more common, one can actually buy them for less than a 500W kit. There will be no range difference at ridden at the asme speed. In fact the 1000W kit may have better range than the 500W kit because it will be more effcient under heavier loads.

It's the battery that weighs and costs less when current capacity is less. But if course you're going to recommend your fire hazard toy airplane batteries without BMS to another noob.

 

[wesnewell]

Some people are intelligent enough to safely use any battery, Others aren't intelligent enough to use any battery. Noob has nothing to do with it. I had never even seen a rc battery when I started using them. I wouldn't use anything else today, although there may be good alternatives in the near futur. I don't consider 18650's or lifepo4 good alternatives.

 

[highlander]

Ok, I'm getting close.

Bafang CST motor - seems to be out of stock at bmsbattery.
http://www.elifebike.com/peng/iview.asp?KeyID=dtpic-2013-9T-F37E.74VMQ
Options: 36V 500W, with controller, PAS, throttle, brake lever
I think its 205 RPM. I'm getting a 26" wheel.

Should I scrap the extras and select them separately? The S12S controller sounded like a good option from what I read in that other thread

Battery is tbd

 

[motomech]

I like E Life Bike and order a lot of stuff from them, but that is the wrong speed motor. Like D8veh said(and you should take his advice since he is the most knowledgeable Ebike guy on the Planet), you want the 270 rpm @ 36V motor(Which IS in stock at BMS Battery) unless you want a 16 to 18 mph Ebike..
Also, unfortunately, ELB doen't offer a controller compatible to the BPM.
Is there a reason you want to keep stumbling around in the dark?

 

[highlander]

I like E Life Bike and order a lot of stuff from them, but that is the wrong speed motor. Like D8veh said(and you should take his advice since he is the most knowledgeable Ebike guy on the Planet), you want the 270 rpm @ 36V motor(Which IS in stock at BMS Battery) unless you want a 16 to 18 mph Ebike..
Also, unfortunately, ELB doen't offer a controller compatible to the BPM.
Is there a reason you want to keep stumbling around in the dark?

My main design requirement is climbing a couple steep hills in my neighborhood. I'd guess the biggest one is about 200m at 8-10% grade. That is why I was thinking the lower rpm for higher torque. I can live with lower speeds

 

[motomech]

But a BPM 270 on 30 or so Amps(48 Volt)will climb hills steeper than you can walk up. Well, almost, but still, I would only use a 201 lrg. geared for off-road.
You are just giving up some speed for very little in return.
I ride like a grandpa, very low-power assist bike and even for me, 18 mph all the time is slow enough to be boring.
22 to 25 mph is the sweet spot for most folks.
Oh well, do it your way, but I have ordered much stuff from BMS Battery over the years and if you are interested, I can relay some of my experiences with them.
I will say this, they probably have the best batteries for the money(excluding Lipo) and if you make an order from them, you should think about ordering one of theirs at the same time to consolidate on the shipping costs.

P.S. I ran the CST, 35 A controller on 48 V climbing a 10% hill on the Ebike CA sim....
http://www.ebikes.ca/tools/simulator.html
...and time to over-heat was 6 min. with a low speed of a little over 20 mph.
That is saying, "bring it on".

 

[highlander]

I'd trust your experience over my thoughts, thats what I'm here for. I guess I'll go for 270.

What material battery would you recommend?

 

[motomech]

Well, my experience pails compared to Dave's(D8veh). He is a semi-pro Ebike tester in England and has built or tested scores of different type Ebikes. Mostly, he posts over at pedelecsuk.com.
If you go there, he has some pics of the bikes he has built including several BPM rear motor builds.
This is the motor/wheel ASM we are talking about;
https://bmsbattery.com/ebike-kit/589-bafang-36v-cst-rear-driving-e-bike-motor-wheel-ebike-kit.html
The spokes are usually loose, so you need to order a spoke wrench.
Battery- I use Lipo mostly, but most riders think the Li-Ion offer the best balance of lite weight/power/service life. I liked the ones I have used.
The folks over at pedelecsUK have looked at the ones with Panasonic cells and they are the real deal. They think they are worth the extra $$$.
For a controller, there are two types, square waves and sine waves. The sine waves use a display that has all kind of features and info. They require some time programming and set-up, but if you are a "techy" kind of person who enjoys that kind of thing they offer a great deal of stuff for the $$. The square waves are more simple and require less time to setup. I would recommend that you study the manuals(avail. @ the bottom of the product page) for the controller and the LCD-3 display.
You want one in the 25 to 35 Amp range. You need to make sure the controller will not exceed the rating of the batt.
When ordering from BMS Battery, it's the freight that's a killer, so it pays to make sure you order all the little stuff. We actually order some extra things like throttles, etc. I like left-hand, half-twist throttles and BMS B. is one of the few places to get them. I suggest you order different types till you see what you will like.
You will also need;
2 pr.s of torque arms
speed sensor, not the King.
both types of PAS sensors(They are bike dependent for install and I can't which will work on your donor bike).
When ordering from the big vendors in China, two things are really important;
Get your list right, because if something is wrong, they will not tell you
and
Communication, talk to them via Email, before the order(like "please confirm motor speed") and right after the order.
After you pay(use Pay Pa)l, you won't hear anything for a week and just when you really start to wonder, you will get a tracking numer and the stuff will arrive a day or two later
Under no circumstances agree to pay extra shipping costs, just let us know if they try to pull that crap.
I can't garrente everything will come perfect, but it usually does.
I have lost some money over the years with them, but I also have saved a lot too and it has worked out well for me.
When your list is ready,post it and we can review it.

 

[Eteck]

Bafang CST motor -
http://www.elifebike.com/peng/iview.asp?KeyID=dtpic-2013-9T-F37E.74VMQ

The efficiency is listed at >=78%. The Chinese 48V 1000W kits found all over Ebay are listed as >=80%.
If you look at other brands you can find >=82% hub motors.

If your going to purchase separate I would get a higher watt hub and run it at 36V. You said you have some steep hills so less chance
of overheating the hub and more options on increasing the speed at some point.

My main motivation for an ebike is to help me climb the occasional hills that are occasionally steep

A 36V controller will do nicely for this, with almost normal pedal input you can go up a pretty steep hill at maybe 15-17 mph.

 

[d8veh]

The question is how hard you want to pedal. If you can already do those hills on a non-electric bike, even the smallest motors will give you what you want, especially with your low weight.

Considering what you've said so far, I think think a 500w Bafang CST is more than enough for what you want. I think you'd be OK with 20 amps at 36v or 15 amps at 48v, which means that you can use a smaller controller for easier installation. I like those 09 bottle batteries with the included 20A sine wave controllers because they make a neat installation, but if your motor doesn't have a speed sensor, you have to solder a couple of wires in, and they're not completely waterproof.

Her's my present bike that might give you some ideas. It's 48v with a 15A controller in that saddlebag and a small hub-motor (Xiongda). I'm 100kg (220lbs) and I have lots of steep hills around. Some as steep as 30% in short sections. It's a bicycle, so I pedal it, though not with any serious effort (unless I'm racing a roadie). It will cruise happily at 20 mph on the flat and maxes out at about 24 mph with an all-up weight of 21kg.

 

[highlander]

My main design requirement is climbing a couple steep hills in my neighborhood. I'd guess the biggest one is about 200m at 8-10% grade. That is why I was thinking the lower rpm for higher torque. I can live with lower speeds

Slight amendment...I had the wrong idea of % slope. My neighborhood hills are ~10 degrees, so ~17% slope