First timer, looking to DIY and looking for advice.

Greetings folks!

I've recently become interested in building an e-bike, and I'm looking for input. I'm looking to modify a basic sturdy steel frame 24" bike to an e-bike that can go 20-30mph with a range of around 10 miles on mostly flat, paved terrain with some hills. I also want to be able to pedal the bike, or at least have the option of meaningfully pedaling, especially on a rare steep hill. I'd also like it to be as quiet as is reasonably possible. I' d like to use it to make a quick trip to the store a few miles away a few times a week and to scoot around campus on a daily basis.

That said, I understand that I'll need somewhere between 500w and 1kw of power. Since this is my first time at it, simplicity is very important (I'm mechanically inclined but mechanically inexperienced). In that regard, from the little I know, I may be looking for a direct-drive hub motor. I've got a budget of $500 (but naturally the less expensive the better), and I live in the continental US.

Are there any good kits out there that'll fit the bill? If not, what motors would you recommend, and from what retailers? What sort of drive system would suit me best, and how would I best go about timing it? And as for batteries - to be honest, I do not want to dump an unreasonable amount of cash into them. I understand that lead-acid batteries may fit the bill for me. And controllers? And everything I missed?

Any input is greatly appreciated, thanks.

Aaron

Welcome, Aaron. Looks like you've done your ebike homework and have a very good handle on what you need to meet your goals. Your budget is pretty tight, but doable if you use SLA batteries.

A good, complete kit for you would be something like this:
http://www.poweridestore.com/Hub-Motor-Kits/Rear-Single-Speed-Kit/Model-408-Rear-Single-Speed-500W-Hub-Motor-Kit
A crystalyte 408 rear hubmotor with freewheel in a 24" wheel with a 36v-72v 20A immediate-start controller, and 48 volt SLA battery pack. The price is about $600 though. You could probably get the price down to $500 by shopping around and buying the pieces individually.

Of all the hobbies I've come across, this one seems far more practical than most. That said, I get the feeling that this is one of the infectious ones, where after your first one all you want is more - more volts, more amps, more mph.

It looks like I'm convinced by the hub motors. If I take the plunge, I'd much rather make a larger investment in the first place than want more once I do drop my hard-earned cash. So, I'm willing to be a bit flexible on the budget for the time being.

Can you tell me more about Crystalyte's motors? I gather they're the only game in town. What are the various series, and would they be appropriate for me? I found a link to http://electricrider.com/ in another thread, and I like what I see. Honestly, who doesn't like the idea of going 35mph on a bicycle? Is a 40 amp 48 volt Phoenix Racer considered one of the high-end options out there? I gather that its real name is the X-5 series motor. And can it be run at higher voltages? I see that there's a 72v 40a controller out there for that motor, and I'm sure 50% more voltage would mean a noticeable speed bump. Of course, now we are talking about a $900 system...

But what I'd be interested in for that cash is a very high top speed, not a mountain climber. In that case, what would I want to look at?

lazarus2405 said:

Of all the hobbies I've come across, this one seems far more practical than most. That said, I get the feeling that this is one of the infectious ones, where after your first one all you want is more - more volts, more amps, more mph.

Click to expand...

And less weight and longer range and 15-minute on-board recharge and.....

Can you tell me more about Crystalyte's motors? What are the various series, and would they be appropriate for me?

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Sure. Like most but not all other brands, the crystalyte hubmotors are all brushless motors (no brushes to replace, more efficient). There's two basic versions, with different winding types within those versions. The different winding types are denoted by the last numbers, the different basic versions by the first numbers. The winding type is simply how fast per volt the motor goes, and like gears, the faster motors develop less torque than the slower motors. A 408 goes faster per volt than a 409, but slower than a 406. More on that here:

http://www.ebikes.ca/hubmotors.shtml

Here's an excellent tool here for visualizing the differences:
http://www.ebikes.ca/simulator/

It'll probably take a little time to figure out what the curves mean in a practical sense, but it's worth figuring out so you buy the best motor for your terrain and riding desires.
The two basic types are the 5000-series (also called the X5 around here) and the 400-series. The 5000-series weighs 25lbs, the 400-series 12lbs. The 5000 series handles 5,000 watts continuously without overheating, the 400 series about 2,500 watts but with a lot more heating. For 1500 watts or less, there's really no benefit to the much heavier 5000-series. If you want to build a bike with performance on par or better than a 50cc moped, then you'll want one of the X5's.
There's also a new motor from crystalyte called the Cannon that is supposedly is between the 400 series and 5000 series in most measures. Not much is known about it yet.
There are also other bicycle hubmotor kit brands such as Heizmann and Wilderness Energy you may wish to look into. Being the best understood and most popular, there's a lot more options as far as parts and upgrades when using the crystalyte kits.

I found a link to http://electricrider.com/ in another thread, and I like what I see. Honestly, who doesn't like the idea of going 35mph on a bicycle?

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We have a member here who's ridden his 60mph. But it starts getting pretty scary for me above 35mph, mainly because obstacle/pothole avoidance is such an issue with a bicycle at high speeds -- as in they aren't made to withstand those kind of hits.

Is a 40 amp 48 volt Phoenix Racer considered one of the high-end options out there? And can it be run at higher voltages? I see that there's a 72v 40a controller out there for that motor, and I'm sure 50% more voltage would mean a noticeable speed bump. Of course, now we are talking about a $900 system...

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The Phoenix Racer is the 5303 hubmotor, and is on the high end as far as power capability and speed. The torquier "cruiser" -- the 5304 -- is generally the best option of the three if you run at voltages above 48v. I have a 5304 in a 20" wheel that I'm running at 80 volts 35 amps (2,800 watts). Top speed is 40mph.
Speed is directly proportionate to voltage. The same system will go twice as fast with twice the voltage, so long as amperage (which correlates with torque) is sufficient to cut through the wind resistance.
The trick in selecting the right crystalyte motor is to:
1) match your expected total power input to the right type, IMO and with a bit of oversimplification: either the 400-series for <1500 watts, or the 5000-series for more than 1500 watts.
2)After deciding between the 400 and the 5000, select your winding type, wheel size, and voltage to maximize the torque you get while still meeting your speed requirement. I originally bought my 5304 in a 24" wheel, but found I never rode over 35 mph (when the top speed was 45mph), and that I wanted better off-the-line acceleration and better hill-climbing. So I downsized to a 20" wheel.

Maximizing these parameters also maximizes your system's efficiency, which means maximizing your range.

If you think you might want to increase voltage later, definitely go with one of the 72volt controllers. The 72 volt 40 amp is the most flexible. You can feed it anything from 36 to 84 volts, and having more amps means more torque for better hill climbing and acceleration. More volts also means better hill climbing and acceleration, but more volts also means higher top speed, whereas more amps doesn't increase top speed unless you have so few as to be unable to cut through 30 mph of wind resistance (an issue with 20 amp controllers)

So I would do well to decide what "cruising" speed I want and then to maximize my torque at that speed. And in general, when buying motors I should to for the torquier ones, as I can always add more voltage later. In general, the more torque I have, the more of a "raw power" sensation the bike will have accelerating, and (beyond a certain point) more voltage will equate to more of a "oh my god I'm going to kill myself on a manhole cover" sensation.

Does all that above sound correct?

Do all sellers of Crystalyte motors sell them laced in spokes and rim? Are there any I would need to beware of that would sell me just the motor? I can see that being one of the most disappointing UPS visits in recent memory.

And what is the ballpark difference between the energy densities of SLA and NiCad? A factor of 2? 4ish?

The ebike simulator that you linked is very useful. However, it does not estimate wind resistance. Though, I can add that in using the drag equation, and find the torque needed at a specific speed to overcome air resistance. Since it's proportional to the square of the velocity, I figure it becomes an issue, but only long after those manhole covers.

lazarus,

You might also find this useful:
http://endless-sphere.com/forums/viewtopic.php?t=538&start=2

lazarus2405 said:

So I would do well to decide what "cruising" speed I want and then to maximize my torque at that speed. And in general, when buying motors I should to for the torquier ones, as I can always add more voltage later.

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Yes. Power = Volts X Amps = Speed X Torque.
Adding voltage (and hence speed and power) later is an easy as adding more batteries in series. Adding torque requires a new motor, new controller, or major modifications to the existing motor or controller.

In general, the more torque I have, the more of a "raw power" sensation the bike will have accelerating, and (beyond a certain point) more voltage will equate to more of a "oh my god I'm going to kill myself on a manhole cover" sensation.

Click to expand...

That's one way of putting it.

Does all that above sound correct?

Click to expand...

Yes.

Do all sellers of Crystalyte motors sell them laced in spokes and rim? Are there any I would need to beware of that would sell me just the motor? I can see that being one of the most disappointing UPS visits in recent memory.

Click to expand...

Most do (or will) sell the motor pre-laced into the wheel. I'd send the vendor an email just to make sure. Depending on your bicycle experience and the type of spoke lacing pattern employed, spoking your own wheel properly can be a major challenge, or pretty easy.

And what is the ballpark difference between the energy densities of SLA and NiCad? A factor of 2? 4ish?

Click to expand...

Nicad and NiMH have about twice the energy density of SLA. NiMH is a little lighter than Nicad.

The ebike simulator that you linked is very useful. However, it does not estimate wind resistance.

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Combine the hubmotor simulator results with the bicycle speed and power simulator:
http://www.kreuzotter.de/english/espeed.htm

Though, I can add that in using the drag equation, and find the torque needed at a specific speed to overcome air resistance. Since it's proportional to the square of the velocity, I figure it becomes an issue, but only long after those manhole covers.

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And grates, and rocks, and squirrels, dogs, truck-blown debris, kids, cars, potholes, ruts....

40amps 48 volts is a good starting place that'll work nicely with any crystalyte motor you choose, or most other hubmotors too.

Quote "
Nicad and NiMH have about twice the energy density of SLA. NiMH is a little lighter than Nicad. "


Actually.. nimh/nicad weigh almost the same per AH... but Nimh is smaller in size by aprox 30 % ( Better energy density )

Thanks a bunch for your replies. You've been extremely helpful. But, questions still abound!

In what situations would a front wheel motor be preferable to a rear wheel one?

What is the easiest way to charge multiple 12v batteries when they're wired in serial?

The bike I'm thinking of using is unsuspended. Will this be a problem on paved surfaces at moderate speeds?

Hub motors are always mechanically engaged. How much extra resistance does this add when under only pedal power? I'm sure my eventual usage patterns would make this an almost silly question, but...

lazarus2405 said:

In what situations would a front wheel motor be preferable to a rear wheel one?

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If you search, you'll find many threads about whether to choose a front or a rear hubmotor. In short, unless you use beefy forks and torque arms, the torque developed by systems over 1000 watts will shred front dropouts, resulting in the wires being ripped from the motor as the motor takes off on its own down the street without you -- with potentially catastrophic consequences for the bike and its rider. Most people, myself included, think the ride is all-around better with the motor on the rear, and it's easier to maneuver the bike up onto curbs or over other obstacles. Rear dropouts are generally strong enough to withstand the torque, but there's still been accidents because the bolts weren't tightened enough, or loosened on their own, resulting in the rear hubmotor hopping out of the dropouts. At least having the rear of the bike dive into the ground is not as bad as the front. For high power 5000-series systems, torque arms for the rear are still advisable. I cut my own from stainless steel:

What is the easiest way to charge multiple 12v batteries when they're wired in serial?

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The easiest way is to use the appropriate voltage SLA charger. 12v, 24v, 36v, and 48v are common SLA charger voltages that can be had for $20 - $40.
http://tncscooters.com/partsdb.php?class_type=Electrical%20Parts
Multiple chargers can be used in series with certain caveats that can be discussed if you want. For instance, a 72v SLA pack can be charged simultaneously with two 36v chargers. Having an extra 12v charger on hand is useful for balancing the batteries occasionally (bringing up all the batteries in the series string to the same max voltage). Balancing SLAs with a cheap 12v charger will pay for the charger in increased battery life. SLAs lose capacity when left at less than full charge, even for a few hours. This can be a problem for people who commute to work, unless they can recharge at work. Other chemistries do not have this limitation.

The bike I'm thinking of using is unsuspended. Will this be a problem on paved surfaces at moderate speeds?

Click to expand...

Depending on how smooth the pavement is, the lack of suspension will probably lower your maximum comfortably-safe speed.

Hub motors are always mechanically engaged. How much extra resistance does this add when under only pedal power? I'm sure my eventual usage patterns would make this an almost silly question, but...

Click to expand...

Good question. This drag is called the motor's 'cogging torque'. Unfortunately, the stronger the motor, the worse the cogging torque. I understand that the drag is barely noticeable on the 400 series. My 5304 becomes hard to pedal above 10mph -- the cogging torque increases with speed. I can pedal my freewheeling Currie ebike about 2mph faster. Below 10mph, the drag isn't noticeable. As you rightly noted, cogging torque is usually a non-issue because you can always negate it with a little throttle. The Puma hubmotor uses an internal freewheel, and so doesn't have this problem because the motor is only engaged when moving forward under its own power. The Puma has other advantages as it also uses internal gearing, and has disadvantages that you can read all about on this forum.
http://www.texaselectricbikes.com/catalog/electric-bike-motor-p-163.html

lazarus2405 said:

Thanks a bunch for your replies. You've been extremely helpful. But, questions still abound!

In what situations would a front wheel motor be preferable to a rear wheel one?

What is the easiest way to charge multiple 12v batteries when they're wired in serial?

The bike I'm thinking of using is unsuspended. Will this be a problem on paved surfaces at moderate speeds?

Hub motors are always mechanically engaged. How much extra resistance does this add when under only pedal power? I'm sure my eventual usage patterns would make this an almost silly question, but...

Click to expand...

I know something about cogging. I run one of the crystalyte dual speed motors. its a 4012/408 in one case, with a selector switch on the control. the cogging effect only happens when the controller is hooked up. Short epxlination is the motor cogs because it's trying to be a generator, and it can't if the curcuit is open. This switch has a center off position that opens the curcuit, and eliminates the cogging effect.

On the 408 setting, you can faintly hear something (VERY faint, quieter than the tire noise of slicks) when you coast to a stop from speed, but you feel nothing when peddling. on the 4012 setting, the noise is slightly more pronounced, and while you can't feel it peddling, you can just feel the change in the bike if you flip the switch to off while coasting. .

As for your other questions, the only time I'd consider a front hub is when on ice, or combined with a rear hub for all wheel drive, or if it was free.
Suspensions, is a matter of taste and youth. but the faster you go, the less control you'll have without a suspension. I've been over 30 on my bike before with only a front suspension. I'll make out my will and update my organ doner card before I try it again, and I'm a crazy drunk redneck!

Hello,

I just began doing research on hybrid bicycles and this forum was of the first search returns I came across, so naturally I joined.

This is an excellent thread that has really helped me out, especially xyster's posts.

I have a quick question (whatever that means):

What do you guys think of the EV Tech 900W Brushless Geared Hub Motor Kit (http://www.texaselectricbikes.com/catalog/brushless-geared-motor-p-163.html)?

It seems like a great price and probably a good choice for a beginner like myself, although I would like to run a larger controller & supply if possible with the same motor.

My situation (sorry, a bit lengthy):
I live 7.5 miles from work and commute via a Suzuki GS500E. Sure I get 50 MPG and I get around traffic easy, but I really want to exercise more but I can't seem to keep on my Mountain bike for more than 2 weeks at a time.... You know the story, some mornings I feel tired, or I am running a bit behind, so I will just jump on the Motorcycle, and before I know it, the tires on my bike have gone flat and it gets moved to the back of the garage (out of sight out of mind). But man, if I could just have a higher average speed on the Bicycle, like double, I know I would rather take it!

A little bit about myself:
I am 27 years old and am a part time student in my Senior year working towards my ME degree. I am the proud original owner of a 1997 Klein Mantra dual suspension XS mtn bike and have been an avid rider ever since.

Riding my Mtn bike to work, I have substituted 1.5" 70 psi slicks, and my commute, 7.5 mi of pure 100% flat valley roads, takes 19-23 minuets (compared to about 12 mins on the Motorcycle). I do a lot of on and off road riding with this bike in the Sierra Nevada Mountains, which is why I am able to maintain 17 MPH into face wind or 22 MPH with out wind, all pedal power.

I've read how many 400watt systems can take a bike to 15 or 18 mph, but come on, I beat that on a dual suspension bike with no assist.

So my goal for a Hybrid bike is to buy an inexpensive used dual suspension bike (No way am I going to mutilate my Klein) and ride to work averaging 30 mph or better if possible. Ideally I would like to have all this for $1,000, but of course like other hobbies, I am willing to go a bit more.

Of course the X5 (Phoenix Racer / 5303) would be SA-WEET, but! I think I would rather take this one step and a time and learn as I go. Eventually I would like to run that motor and a 72v setup, but for now I just want to keep it simple and start my learning on a good simple path, and this is why from what I've seen the 900W kit from EV Tech seems pretty decent.

Thanks for your replies! It will be until late Jan. before I am ready to do this. Hopefully I'll have figured out all the choices by then!

Regards,
BigMike

now that these come laced into a rim - and with a 25a controller - i'd say go for that. I'm not surue what the max voltage that controller supports is, but the motor is very good.

it technically wouldn't last as long as a crystalyte, as the crystalyte has no gears or freewheel mechanism to destroy, but the benefits of the puma (that one at texas electric bikes) more than outweights them.

does anyone know what speed puma the ev tech ones are?

Thanks for the info BigH.

Hmmmmmmm I didn't really consider that bit of info... I prefer a gearless setup as it is more efficient at higher rpms. I will only be riding 7.5 mi per trip anyways so range shouldn't be any concern.

I don't need much torque, acceleration is not a big concern as I can accelerate as fast as I need to by pedaling.

I just want some extra assist to take my average speed from around 20 mph to more like 30 or 35. Any higher than that and I think I might run into gearing problems....

Hmmmm........ Let me see...

I currently pedal comfortably at 20 mph using 26x1.5" slicks with a 42t chainring and a 12t rear cog.

To match this same cadence at 30 mph with the same tires, I will need a 53t chainring and an 11t cog. Fortunately this gearing is possible using a road crank, so this will certainly be a must! Anyone know of any 60+ teeth chainrings? :lol:

At this speed (30 mph) the tires will be rotating around 380 rpm. Is this a safe working speed for a geared motor such as the 900w EV Tech motor linked above?

Thanks again,
BigMike

I'm sure you've already seen this, but here is a nifty video of the X5 motor turning some impressive rpms:
http://youtube.com/watch?v=PduUnwgXtiY


I wonder what the gear reduction is on the EV Tech motor... Looks like an email question for them is in order!


BigMike

Nevermind on the rpm range of the motor, I am sure it can handle 380.

I emailed EV Tech and am awaiting their response.

A bit of searching turned up this informative site regarding "a" puma motor, but I don't know if it is the same or not:

http://www.armybikes.com/pumahubkits.htm

Also, is this the same motor?
http://endless-sphere.com/forums/viewtopic.php?t=541&start=0&postdays=0&postorder=asc&highlight=

BigMike

The EV Tech motor is the same as Maytag's. They have been hard to find in stock.

The "Puma" motor is similar, but not exactly the same.

I wouldn't worry too much about the gearing. Who wants to pedal all the time anyway?

Great, thanks for the information.

I love pedaling and pushing myself to keep pace. With the e-assist I'll just be keeping pace at a much higher rate of speed

I am really excited about this. I have started my fund and will start a project thread next month once I get going with it 8)

Happy Holidays everyone!