How can I build a 30mph e-bike?

[Aerros]

I'd like to convert my bicycle into an e-bike (Attached is an image of my bicycle).

http://s21.postimg.org/ywnix8fk7/CAM00249.jpg

Goal
The goal is to have a max speed of 30mph
and have a maximum range of at most 30miles (achievable at max speed with pedal assist) .

The system needs to allow pedal-assist, as implied.

A rear-wheel motor is ideal.

Budget: under $1000usd

-I'm also thinking of finding a way to mount the battery in the frame
-I'm 150lbs
-Bike+lock: about 17lbs
-I know I need a motor, battery (preferably not Lipo for a beginner like me), Torque arm, and Controller

Bike Specs
Front suspension
9 rear gears
3 front gears
(I'm probably missing information)
_____
I'd like to know how any of you would build this as If my goals and bike were your own.
Although this is my first post, I've been researching on and off in the forums but am still confused enough to finally ask for help. I want to get everything right the first time and I'd definitely appreciate any input at all.

Thanks : D

 

[Ykick]

Not a bad frame IMO and it looks like you already ride it a bit - if it's your pic?

30 mile range is gonna be a problem though. Particularly, topped at 30 MPH - that's a good size triangle but I'm skeptical of enough battery to do what you seek.

Range is mostly about how fast you go. Hills, starts, stops, pedaling all factor but the MAIN DRAIN is speed. 15-20MPH, 30 mile range wouldn't be too far fetched with a large battery. 30MPH? "gonna need a bigger boat"

 

[cam3087]

Yescomusa hub motor kit ( look in search) falcon ev frame bag ping 48v 15ah for about 25 miles. You can parallel another 48v if need be for more distance this should run you about 900. The look for then topic of hidden ebike cost.

 

[Tommy L]

Hello.....Tommy L here....

A good thing to learn is Watt Hours. Understanding this and sizing your battery for your needs is golden info for Ebikers old and new alike.

I was out today with a 15kph/10mph wind and was using 1200 watts per hour @ 50 kph/30mph.

1200 / 50 = 24 watt hours per km or
1200 / 30 = 40 watt hours per mile.

So to go 30 miles you would need a 1200 watt hour pack at 100% depth of discharge.
add at least 20% reserve to only use 80% of your available energy, so 1500 watt hour pack would be a minimum for 30mph (Mild Hills, Mild Wind)
A bigger pack if you are in extremely windy/hilly areas.
A 1500 w/h pack (1.5kw) with charger will be a big expense.
If using A123, Cells and a charger and a BMS of sorts will use your budget.

I use LiFePO4 A123 cells. Please learn about cells and batteries/chemistries/electronics before you attempt any project involving Lithium or any electric source.

Read read read.... ask questions and stay safe!
Tommy L sends...

 

[Aerros]

Maybe I should realistically ask for a 15mile range and 25mph max? Thanks for the replies so far, btw

 

[Drunkskunk]

That doesn't look like a bad bike to start with, with a few minor problems that can be solved. First being the gears. 9 speed rear won't fit any hub motor. 7 is standard, though some motors can only fit a 6 speed normally, and a 7 if you stretch the frame. They work on a freewheel gear cluster and a 9 speed is a cassette, and not compatible. they also use a different shifter and a different derailer with a different throw between gears. The good news is a Shimano Rapidfire 7 speed shifter is $20-$35 bucks, depending on the source and model. The standard Red geared Shimano 7 speed derailer is $15

The other problem is the brakes. Rim brakes are fine up to 25mph. at 30, you need at least a front disk. Shop around, $50 will get you a top of the line Avid BB7 plus a 160mm disk. (used, or older model on clearance). That's assuming your fork has the mounts for one. A good fork will have them. A trash-tastical walmart fork won't, but you'll want something better at 30mph.

It takes about 2.5 times more energy to go 30mph than it does to go 20mph, so whats good for 20mph will have 2 and a half times more stress on it at 30mph. Its important to keep that in mind, because it affects every part of the bike. That's why mopeds that can only go 30mph are built like tanks compared to a bicycle.


On your budget, 30 miles at 30mph isn't going to happen except on a rare fluke with a 30mph tail wind and no stops on a glass smooth road. dropping your expectations down to 20mph sustained, and you're in the range of possible, but you need to increase your budget some to do it right. the battery need to go 30mph is 2.5 times bigger, and therefor 2.5 times more expensive than it will be for 20mph. Still, at 20mph, its going to be big and not cheap.

When sizing a battery, You need 35 watt hours capacity for every mile you want to travel, at 20mph. That will give you a battery that takes into account normal cycles at 80%, stoping and starting, and reserve to handle headwinds and moderate hills plus the normal degradation over time. All batteries lose capacity over time, you want a battery sized to still be good next year, and they year after, not just this summer. So for 30 miles you need 1020 watt hours at 20mph. That's roughly a 48 volt 20 Amp hour battery. On the cheap end (Ping battery), that's a $700 battery before shipping. Sure, you can find cheaper LiFePO4, but not from anyone I'd recommend. The battery is the one thing you do not ever want go cheap out on. A good battery is far more important than a good motor.

As for the motor, there are many that will suit your needs. On flat ground with fewer hills a 9C (Nine Continents) 2806 will hit 28-29mph.
If you have some steel hills the HS3540 will handle the heat better at about the same speed, but will weigh more and cost more.

 

[Drunkskunk]

Maybe I should realistically ask for a 15mile range and 25mph max? Thanks for the replies so far, btw

That would be a 9C (or clone) 2807 (slightly slower, but better on light off road trails, 26mph) and a 48Volt 10Ah battery. It would fit your budget fine, though the rear gears on your bike would still be a minor issue. keep using the brakes you have, and it would fit in your budget.

 

[lbz5mc12]

The yescomm 36V 800W rear motor actually goes about 27mph. I had one so I'm speaking from experience. A 36V battery pack would be cheaper than 48V. Compared to most of us you're physically lighter so your bike wouldn't require as much torque to go uphill. You can easily squeeze a 30 mile range out of a 15-20A battery pack if you take advantage of downhill sections and pedal a lot. As for the rear of your bike you may have to deepen the dropouts so that the hub motor axle seats properly in them. There are other kinds of rear motors you can get that don't require you to modify the dropouts. Go to Amazon.com, look under sports and outdoors, and type in Currie kit. Under the same category search for south paw 16 tooth freewheel. The kit is $349.00 and the freewheel is $14.99. Then you go to tncscooters.com and buy a 36V 5 pin controller and a 36V 5 pin half twist throttle. Controller= $37.50 and throttle= $16.00. Then you use the rest of your budget for the battery. The kit comes with a battery but just don't use it maybe try to sell it, I don't know. The motor on the kit is 24V 450W but when you put 36V through it that coupled with the 16 tooth freewheel will give you your 30 mph. But you need to have the 36V controller and throttle or nothing will work. With this kit you won't have to modify your dropouts and it looks like from the picture of your bike that there is not much dropout to work with in the first place. Also with this kit you won't need a torque arm. You will need some ability for splicing and soldering though. This should easily keep you under your budget of $1000.00.

 

[geeeyejo1]

The rear gears will likely be a moot point as once E-powered you likely will just use your highest gear. I traded my 8 speed cassette for the 7 speed freewheel on my kit - just swapped in a 7 speed grip shifter - I never even shift gears anymore. The Yescom kit (I would take the 48V15ah route) coupled with a 48v 15ah battery will give you ample range if you keep between 15-18mph and pedal - especially at your weight. You will then have the extra ability to go up to 32mph+ for peak bursts. If you get some new kool stop pads your v-brakes should be fine versus going the disk route - I am 240lbs and have had my bike up to 32mph without any significant stopping issues. Yescom kit + Sunthing28 battery will set you back about $750

 

[Aerros]

Wow, a lot of options to soak in. I'm glad I asked. Now all I'll need is some time to look up and solidify the right kind of build (while considering future advice/options as well). Thanks again for everything so far ^ ^!

 

[mythprod]

I have a yescom (or equivalent) front wheel motor 1000W with 48v 20ah battery. I go 12.5 miles @ 25-35 mph give or take to work one way and charge at work and come back home. I had to come back home without charging one day (not fun ) and estimate I got about 6-7 or so miles before the bms cut it off and I pedaled the rest of the way home. This was in late fall and I'm 215 with approx. 50-60 lb bike and I pedal the entire time. So going as fast as I do at full throttle most of the time I can get a max of 20 miles or so on a charge, if not a little less or more depending on wind, temp and other factors. I have a bike trail I can take as an alternate to the roads and it adds about 15 minutes one way to my trip, but obviously it's the route I take if my battery isn't charged for some reason as I can get a lot farther because I'm going slower and not using the throttle as much due to corners, hills, pedestrians, etc.

If you think you have 15 miles or so to go I really wouldn't get anything less than a 48v 20ah. It's better to have more and not need it.

 

[RLD70]

I too have the yescom motor and Im able to get roughly 35 - 40 miles out of my 48v 20ah lifepo4 pack running 18 - 20 mph and Ill be adding another 10ah pack with the next check to add up to another 10 - 20 miles distance. Find the optimal speed for your motor and you can have some good distances per charge. And dont forget that the terrain, wind resistance, etc. will have the most impact on how far the battery pack will take you.

 

[dogman dan]

I'd start by compromising a few things. 30 miles at 30 mph is totally doable. It's just that the battery won't fit well in the frame. Nor can you buy enough battery in your budget.

First thing to look at is do you really need 30 miles? Or can you charge halfway, as in it's 15 miles to work?

At 30 mph, you will definitely make 15 miles out of a 48v 15 ah battery, which will fit nicely in the triangle. Or it can easily do 30 miles at 18 mph.

All the motor suggestions above work well. You'll have to go cheap to make that $1000 budget. I'd get a less powerful controller than the 30 amps one that comes in the yes 1000w kit, if you are going to get a cheap battery such as from sun thing on ebay. 20 amps will get you close enough to 30 mph. Just won't get to that speed as quick. So the 800w kit and a 36v 20 ah battery might be a great way to go. You'll get 20 miles at top speed.

Ride wary. Cars will all think you are riding bike speed, 15 mph. Brakes won't help much at 30 mph, so learn to dodge cars, and avoid letting them cross you. Ride the safer route is the best thing to do.

 

[arkmundi]

When sizing a battery, You need 35 watt hours capacity for every mile you want to travel, at 20mph. That will give you a battery that takes into account normal cycles at 80%, stoping and starting, and reserve to handle headwinds and moderate hills plus the normal degradation over time. All batteries lose capacity over time, you want a battery sized to still be good next year, and they year after, not just this summer. So for 30 miles you need 1020 watt hours at 20mph. That's roughly a 48 volt 20 Amp hour battery. On the cheap end (Ping battery), that's a $700 battery before shipping. Sure, you can find cheaper LiFePO4, but not from anyone I'd recommend. The battery is the one thing you do not ever want go cheap out on. A good battery is far more important than a good motor.

Sage advise you'll thank your self many times in the following. Rule of thumb: size your battery at twice your calculated need. Again, that's so you've got the juice over time as your battery looses capacity.

 

[Chalo]

Rim brakes are fine up to 25mph. at 30, you need at least a front disk.

People keep saying this, but it keeps being wrong. The right principle is "at high speeds, you need good brakes."

The best rim brakes are stronger than the best bicycle disc brakes. I've been doing this stuff for decades, on single bikes that weighed up to 500 pounds all-up, and other pedal contraptions that weighed up to 3200 pounds loaded. I've tried everything available in the pursuit of strong brakes. There are advantages to discs, but greater braking power is NOT one of them.

If a disc brake has only a 160mm rotor, you're better off with a good solid linear-pull brake-- with good pads, proper adjustment, and careful cable routing and prep. In the best case, you also have a booster arch to stiffen up the mounting studs. Small rotors get hot quickly, causing brake fade followed by damage to the brake's plastic parts (or hydraulic lock in the case of hydraulic brakes).

 

[emiyata]

Rim brakes are fine up to 25mph. at 30, you need at least a front disk.

People keep saying this, but it keeps being wrong. The right principle is "at high speeds, you need good brakes."

The best rim brakes are stronger than the best bicycle disc brakes. I've been doing this stuff for decades, on single bikes that weighed up to 500 pounds all-up, and other pedal contraptions that weighed up to 3200 pounds loaded. I've tried everything available in the pursuit of strong brakes. There are advantages to discs, but greater braking power is NOT one of them.

If a disc brake has only a 160mm rotor, you're better off with a good solid linear-pull brake-- with good pads, proper adjustment, and careful cable routing and prep. In the best case, you also have a booster arch to stiffen up the mounting studs. Small rotors get hot quickly, causing brake fade followed by damage to the brake's plastic parts (or hydraulic lock in the case of hydraulic brakes).

I have disc brakes on the bike and they work well, but I can get the same amount of braking from rim brakes. With a tight budget I would use rim brakes and get some good new pads.

 

[Aerros]

Are there no USA dealers for battery packs? It's 2013 already! I might invest the 2month shipment time into learning how to make my own battery packs (soldering, electrical know-how). Then again, I may not. It all depends what I find in some more research. But if I were to settle on a build right now, it would be the 36V 800w motor and 36V 20ah LiFePO4 battery pack (I can live with that choice). Thanks for all the information again. I'll need to upgrade my brakes for sure as well.

 

[chas58]

Finally, the voice of reason.

Yeah, you need good brakes, whichever type you choose. But, there isn't just one type. I can ride fine on a 400lb Gross weight tandem at 20, 30, 40mph. The only problem is steep hills which can cause the rims to overheat and the valve to leak (fortunately it takes a minute or two for the tire to go flat). Switching to disk/drum brakes I can still overheat them. Shoot, I've overheated the brakes in my car. Either way, you have to be aware of what you are doing to the brakes if you are going to push their limits. It depends a lot on speed and weight and terrain. If you are not doing mountain riding with a ton of weight, you can do a lot with good rim brakes.

Rim brakes are fine up to 25mph. at 30, you need at least a front disk.

People keep saying this, but it keeps being wrong. The right principle is "at high speeds, you need good brakes."

The best rim brakes are stronger than the best bicycle disc brakes. I've been doing this stuff for decades, on single bikes that weighed up to 500 pounds all-up, and other pedal contraptions that weighed up to 3200 pounds loaded. I've tried everything available in the pursuit of strong brakes. There are advantages to discs, but greater braking power is NOT one of them.

If a disc brake has only a 160mm rotor, you're better off with a good solid linear-pull brake-- with good pads, proper adjustment, and careful cable routing and prep. In the best case, you also have a booster arch to stiffen up the mounting studs. Small rotors get hot quickly, causing brake fade followed by damage to the brake's plastic parts (or hydraulic lock in the case of hydraulic brakes).

 

[lbz5mc12]

I think what happens to people when they're using their brakes is that they're not giving themselves enough room to brake. When they ride a regular bike they don't have to apply the brakes as soon to stop but when you're on an e-bike you're going the same speed/or faster but with more weight depending on the terrain so you need to begin to apply the brakes sooner before you stop. I prefer linear brakes to disk brakes for another reason. If something is wrong with your rim you can usually tell when you apply your brakes but with a disk brake it's not rubbing on the rim so you may have a serious problem that is going unnoticed.

 

[wesnewell]

http://endless-sphere.com/forums/viewtopic.php?f=3&t=26488#p717771

 

[full-throttle]

Rim brakes are fine up to 25mph. at 30, you need at least a front disk.

People keep saying this, but it keeps being wrong. The right principle is "at high speeds, you need good brakes."

The best rim brakes are stronger than the best bicycle disc brakes.

Out of curiosity - which hydraulic disc brakes have you actually tried?

I prefer linear brakes to disk brakes for another reason. If something is wrong with your rim you can usually tell when you apply your brakes but with a disk brake it's not rubbing on the rim so you may have a serious problem that is going unnoticed.

Isn't it funny reading all the lame excuses for not being able afford quality parts. Do you also prefer to eat out of the trash because you can tell each time when you catch salmonella?

 

[wesnewell]

http://www.ebay.com/itm/48V1000W-26-Rear-Wheel-Electric-Bicycle-Motor-Kit-E-Bike-Cycling-Hub-Conversion-/400446727757 $285
http://www.hobbypartz.com/75p-1220-charger.html?gclid=CNa3z9_N57ICFayPPAod10MAPw $90
http://www.hobbyking.com/hobbyking/store/__16207__Turnigy_5000mAh_6S_20C_Lipo_Pack_USA_Warehouse_.html x12 $512
PSU and misc. $113
Total $1000

 

[Chalo]

Rim brakes are fine up to 25mph. at 30, you need at least a front disk.

People keep saying this, but it keeps being wrong. The right principle is "at high speeds, you need good brakes."

The best rim brakes are stronger than the best bicycle disc brakes.

Out of curiosity - which hydraulic disc brakes have you actually tried?

Shimano
Hayes
Hope
Magura
Avid
Formula
Mountain Cycle
Sachs

Various models of each. I might be forgetting some, but all the above makes of hydraulic discs are familiar to me.

I'm a cycle mechanic, you know. Been wrenching in bike shops since 1992. I don't need to have bought hydraulic discs for myself, because it's part of my job to set these things in order and then to test them. What I know about bicycle disc brakes I know from direct observation.

 

[full-throttle]

Well, if you going to say that either of: Formula TheOnes, Shimano Saint M820, Hopetech V4 are not as powerful and consistent as any rim brake out there, I'm calling you a liar.

PS I have also worked as a bike mechanic during studies, so no BS please.

 

[Chalo]

Well, if you going to say that either of: Formula TheOnes, Shimano Saint M820, Hopetech V4 are not as powerful and consistent as any rim brake out there, I'm calling you a liar.

PS I have also worked as a bike mechanic during studies, so no BS please.

I don't think I have worked with any of those specific models. And I have never said that disc brakes lack consistency, either. They are certainly consistent-- good or bad. What they are not is stronger than the strongest rim brakes.

There is a difference between a schoolkid working in a bike shop as a sideline, and a technician with decades of relevant experience choosing to work in a bike shop in his forties. I used to be that young guy (though I had finished five years of college before I started wrenching)-- but to be frank I would not really want that young guy to work on my own bike, knowing what I know now.

The young guy in the shop is apt to do a much better job setting up a pair of pre-bled hydraulic discs than high-performance rim brakes, because there isn't very much to it. Just as with boutique wheels, I think this is one reason the industry has bought into discs so heavily. You don't need skillful workmanship to get passable results.