Electric Bikes - Engineering student needs suggestions: Solar-Electric Trike!

Hi, I'm a senior engineering student and I've chosen to build an electric-solar bike for my senior project. :thumb:

So far I have a brand new Schwinn Meridian adult tricylce and about 66 A123 LiFe batteries (loose cells).
http://i.walmartimages.com/i/p/00/03/86/75/40/0003867540013_215X215.jpg
I've been trying to decide on what motor system to go with and what other components I will need.

With a 36v setup, I'm at 36.3v on a full charge. I have enough batteries to put 11 in series, 6 in parallel, giving me a 19.2 Ahr pack.
With a 24v setup, I'm actually over voltage to 26.4v on a full charge with 8 in series, 8 in parallel, giving me a 25.6 Ahr pack.

What's better 24V or 36V?

At first I was looking at a 600W 24v brushless motor, but then I realized that I would have to design mounting brackets and a pully system to hook into the chain... then I started looking at hub motors and right now I'm looking at a 600W 36V brushless hub motor.

Basically the hub system would save me a lot of time and money by not having to design and build the mounting system for the motor. Are there any major drawbacks of using a front hub motor instead of a normal motor running the back wheel(s) by chain?

Also, can anyone recommend a good controller/charging system to use with my LiFe batteries? You can quick charge these cells at up to 10A per cell in parallel, so most chargers won't give me as good of charge times as I could get. Most controller and motor systems I've been looking at give very little specifications as to maximum RPM, voltage range, amps, how to set cutt-off voltage (if you can set or adjust it), if it's compatible with brushless motors etc... These LiFe bats have high power capabilities, what system will let me get the most out of them?

I was looking at the 1000W systems, but they're a bit more pricey and they don't make them in brushless hubs (as far as I know).

I am also wanting to make sure 600W is enough power for me on a trike and some extra weight. I'm about 210, not sure how much the trike weights, shipping weight is 70 pounds, so I'm guessing around 60 pounds out of the box. Then there's about 10 pounds for batteries and approximately another 10 pounds for other equipment. That makes a total guess at 290 to 300 pounds. I don't need or want that much speed because this is a trike and I'm not sure how well it will handle over 20mph, so 20 is my max. I guess I could always gear down and get a lower top end and more torque. But I'm also thinking that 1000W is a bit more than I need and would probably drain my batteries a lot faster than a 600W.

Any suggestions would be much appreciated! :) I'm new, so be nice!

Hubs of course. 5303 Racers.

Higher the power....the higher the fun factor.

Hubs of course. 5303 Racers.

Higher the power....the higher the fun factor.

Ok, I figured hubs would win, but I'm having problems finding any stats on them and it seems a lot of suppliers are sold out right now. And they all want you to buy the full kit. All I really need is a speed controller and charger that's compatible with my system.

Also, I know I want higher power, but with the hub motor, there's no way to adjust top end/power ratio.

I want a high powered hub that is geared to top out at around 20 to 25. I'm guessing the sweet spot is right between 600W and 750W and probably a 36V system (I'm not going to 48V, I want power and range, not speed).

I think it's a cool project.

Here's a hub site, there are many. Some cheaper hubs are at Goldenmotors, but Electric Rider is stateside. http://www.electricrider.com/

Check http://www.endless-sphere.com/forums/ for mind blowing detail on this subject.

About 30 threads down is some pictures of a trike I built, in "High power recumbent trike", and more in a thread even further back in time, this forum.

I went 48 volt, 40amp with DeWalt a123 packs, and get about 35mph for a top end. Of course you don't have to go full throttle all the time, that will increase your range. It's just nice to have the power if you want it. :)

The answer is, it depends. Inline motors are easiest to install on recumbents or other bikes with long chain lines. The advantage is the motor is lighter and can climb hills and go fast. Hub motor is easy to put on most bikes but is very heavy, doesn't climb well unless you get really heavy and less efficient. However, I am waiting for one of the BMC geared hub motors which are supposed to climb hills and go about 25 mph.

Simpleci: Frame mounted motors that utilize the drivetrain can be very powerful and efficient, as they can be run through variable gear ratios, however your Schwinn meridian is a single speed thus neutralizing that benefit, and you are looking at considerably increasing project complexity to both go with frame mounting and redoing your trike's drivetrain to include multiple speeds.

I believe that from your descriptions of what would best suit your needs, that you are looking for a geared hub motor.

For obtaining torque and efficiency in a hub motor, there is simply no comparison between a geared hub motor such as BMC, eZee or Heinzmann, and between a direct drive system like a Crystalyte. The geared hub motors will simply crush the direct drive variants in efficiency and torque output per watt. They have additional benefits, such as lower weight and freewheeling ability which you may find enjoyable, but for meeting your core requirements of being fed by solar, and having high torque output, a geared motor will provide more value by far.

Out of those 3 mentioned geared hub motors, Heinzmann is difficult to get a hold of and pricier, and BMC is rear drive only I believe. eZee is your best bet, in my opinion.

eZee is available in a front drive variant which is likely to meet your needs for pairing with a trike. You can obtain them from http://ebikes.ca (http://ebikes.ca/) as a package with the motor, controller and throttle - sans battery, so it has everything you need and will allow you to use the cells you already have for your battery pack.

On the ebikes.ca website is also a motor simulator which contains many popular hub motors, including the eZee and the Crystalyte so that you can make some rough comparisons and find out if there are other solutions that work for you. And if you have any questions, the staff are very knowledgeable.

I hope that this has helped, good luck on your project!

First, thank you for your replies they have been very helpful. :)

I looked at the eZee motor, while it does give excellent torque (about 60 lbs thrust off the line), with a 36v system my max speed would be like 15mph.

I think I like the Crystalyte 5304, AKA the Phoenix Cruiser... with a 36V40A controller, I can get a good 45 lbs thrust off the line and a top speed around 25.

So... I'm looking at about $750 for the 5304-F26, 36V40A Phoenix controller, twist throttle, wiring kit, and torque arm(do I really need a torque arm?).

Man... this is going to be a pricey project. I'm hoping my parents will help fund me, cause I don't want the school to pay for it then want to keep ownership when I'm done.

Now.. Chargers! What good chargers are there out there that can do my A123 LiFe batts reliably. These batteries have a different charging algorithm than other batteries, so I need to make sure I get one that works right. Or there's also a kid at school who said he had designed a circuit that would do it, but not at that high of volts. He was using it for model airplane batteries...

I also have another question... With this higher power system (~1400W), will I get a noticeable decrease in range over using a smaller 600W system? Or does the higher power cancel out in range calculations? It seems like it should since you can reduce range to available power (Ahr) and applied power over time (W), so more watts just means you get there faster right? Of course you still have to consider system inefficiencies such as heat loss. Higher power systems will probably generate more heat...?

Ah, you might want to che k out my post on my experiences building a solar - electric trike, just scroll down the page until you see "Solar charged e-trike". For me, a hub motor was the only way to go, started with a Wilderness Energy 'Pedal first' 400W BL36, but with 150# of trike, 36v 12ah sla batts, solar, other 'schtuff', I needed more 'umph'! Went to a C'lyte X5303 w/ 36v40a controller - plenty of speed now. My record load (trike, solar, me and 120# of bagged concrete) is 520#! Rode home at 41wh/mile on a cold day. Lesson learned? Need a better trailer, LiFePO4 or NiMH batt set. Problem is, LiFe packs are only rated at 1.5c (Ping), NiMh packs (ebikes.ca) at 3c, and the Cycle Analyst says that my max draw (short term) has been 60a, so, LiFe packs look like a self-fulfilling prophecy for early demise.

Sorry! Back to what you are doing. Until those 40% efficiency panels are available at a reasonable price, real time solar charging is a beautiful promise, only. My cheap amorp. thin film panels at 36v give me only 45w - with the 400w motor, that's 12% real time charge benefit, with the 1440w X5, less than 3% real time charge benefit. So, maybe, as a student you have access to better panels at school, or maybe not.
As far as higher power systems reducing range - it's all about speed - how you use watts available (poor pun, sorry). I'm a 4000 mile/year recumbent trike rider and know I can output about 150 watts for an hour, and then drop down to 100 - 125 watts. Being 60 y/o, at that rate, I want to take a nap, a long one, after riding at a pace of (16 - 18 mph) on a route with about 700 ft gain/loss over 25 miles (12.5 each direction). That's on my Scorpion trike, a nice, comfortable, LIGHT touring recumbent trike. With the solar trike being 4X as heavy, I lean on the power more - especially with a heavy tow load, high wind and/or cold, plus the sla pack puts out well below it's 12ah rating in the cold. So, I can go faster/shorter dist., easier w/heavier load but shorter dist. If I drop the solar from the bike and trailer, I can go faster, farther, easier because of less weight.

Did ANY of this make any sense to you or help in the least? Can't do 'stream of consciousness' writing like I ustacould, sorry!

so more watts just means you get there faster right?

Motor efficiency and wind resistance are nonlinear, so no: More watts means you won't go as far on a charge. Hard acceleration is inefficient, but especially so with direct drive hub motors. The power wasted can be very significant, especially when you realize that your contribution from pedaling decreases are motor input in increased.

Also, I worry about the safety of a trike like that at speeds above what you could comfortably pedal with its fixed gear.

Tourezrick: Well, some LiFe batteries might not be able to supply the current, but the ones I have certainly can produce more than enough amps for even the most powerful motor systems.

These cells are the A123 M1 cells, they can pump up to 60A (rated 70A max) per cell in parallel, meaning a 6 parallel configuration can supply up to 360A. I use them in my 60A brushless RC car and they supply max power without the batteries getting over 100F even on a hot day.

I did a battery pack design last semester for a 200hp motorcycle running 423V and something like 600A, that's 128s8p configuration.... These batteries can do it, they are the best LiFe's on the market and that's if you're lucky enough to find them outside of a DeWalt 36V pack.

Unime: The motor I'm looking at claims 80% efficiency at around 15 to 20mph. It has a max speed of 25 (at 36v), but the efficiency drops off. I think most of the time I will keep it in the most efficient range, maybe even put a limiter on the throttle to keep it from exceeding max effeiciency.

I understand your concern about safety on a trike, but really 25mph isn't that fast and I'd certainly not take a corner without slowing down signifigantly. Plus if I limit the throttle, then 20 is my max and I don't see any serious problems as long as the person riding it isn't stupid or crazy with it.

I guess I might still consider a lower watt system. They do offer a 36v 20A or 25A controller for 725W or 900W total power. It is a bit cheaper, but it doesn't have the power I think I'll need with a 300+ pound load.

Ok... now I'm looking at the eZee again and I'm thinking that really would be a better choice. I just wish it was a bit cheaper... I've sent an email to their sales department to see if I can get them to sponsor me or at least give me a discount since this is for educational purposes. I'm hoping to also get a local solar company to sponsor me with the solar panels I need.. keeping fingers crossed...

My main issue is the extra moving parts (gears), the increased wear and the noise generated from the gears. Has anyone actually used the eZee and know if it's very loud and how it's performance is as far as hill climbing and acceleration from a stop.

AND, how about that Cycle Analyst unit?? Looks pretty sweet, nice functions to it. I think I want that, but I don't know if it will work with anything other than the eZee system.

A123's are better packs than Ping and YESA. Lots of folks swear by the Ping packs, but they are not hauling the heavy loads I do. A recent trip to the lumber yard came in at a total (trike w/motor, batts, me, trailer, solar and 120# of Sacrete) weight of 520#. Sure, I coulda geared down and crawled home at 8 mph or so, or I could pedal hard and use 40wh/mile to achieve a safe speed in traffic, on a cold day with the sla sagging from the cold. Throttles are fine things, in my book!

I wish I had the knowhow to make my own battery packs, but my background is special education, with minors in sportscar racing, martial arts and recumbent trike riding, not EE! Maybe some day soon I'll start to experiment and try to teach this 60 y/o dog a new trick. Until then, it's gotta be storebought for me.

The cycle analyst used in conjunction with their digital crystalyte controller (36-72 volt) would be perfect. Also, I would get the 5305 instead for the extra torque/efficiency and raise the voltage to 48 volts intead. You might have to upgrade to a heavy duty steel front fork - one used for major off-roading. Using the cycle analyst, you can limit speed and or power draw so you can prevent major energy usage (or simply pedal during acceleration).

I'm using that controller right now using 37 volt LiPoly and I'm topping out around 30 mph with the 5303 motor. However, the 5303 is sooo current hungry, I keep on tripping the 50 amp current limit. I've seen it go as high as 80 amps. I've run it at 74 volts also and with that much power, it's VERY easy to hit the 50 amp limit. These Phoenix motors are truly brutal in their power capabilities and would probably benefit from a 200 amp controller! SO, DO NOT use a lower power controller. Get the 48 volt controller and get the 5305. Top speed would be about 25 mph and you'd have gobs of torque for pulling that trike around. Actually, forget the cycle analyst. Keep it simple - get the 4840 controller (analog so it won't cut out like the digital controller), get the 5305 and you're golden. If you really want, get a simply Astro-flight wattmeter and that'll tell you volts, amps, power, energy and you can simply plug that inline with your battery to controller.

Ok... now I'm looking at the eZee again and I'm thinking that really would be a better choice. I just wish it was a bit cheaper... I've sent an email to their sales department to see if I can get them to sponsor me or at least give me a discount since this is for educational purposes. I'm hoping to also get a local solar company to sponsor me with the solar panels I need.. keeping fingers crossed...

My main issue is the extra moving parts (gears), the increased wear and the noise generated from the gears. Has anyone actually used the eZee and know if it's very loud and how it's performance is as far as hill climbing and acceleration from a stop.

AND, how about that Cycle Analyst unit?? Looks pretty sweet, nice functions to it. I think I want that, but I don't know if it will work with anything other than the eZee system.

Wear is an unfortunate consequence of having moving parts, however it is very manageable - the nylon gears on the eZee will last several years of regular use and are very easy to replace. The eZee is a fairly quiet system, it does generate some audible noise but is not loud.

When you compare the hill climbing and acceleration capability between a geared motor such as an eZee and a direct drive unit, at comparable wattages the geared motors are considerably more powerful. You need to run a lot more current through the average direct drive motor to get comparable torque output.

The Cycle analyst is an exceptionally useful piece of hardware, it provides a lot of useful information and the stand alone version is compatible with just about any electric bike (or other light electric vehicle) you can imagine. Given that the voltage cutoff of the eZee is 20 volts, you will want the cycle analyst to set a cutoff suitable for your custom battery pack, as if you go for your 36v proposal, it would be possible to irreversibly damage your pack by letting it run below safe levels, which the eZee controller on its on would let you do, unless you programmed a cutoff into your BMS.

I don't know... I compared the eZee to the 5305 hub with a 36V 20A system and really there isn't much difference. The eZee has a few more pounds thrust off the line (42 vs 35), but the 5305 has a higher efficiency rating in the 15 to 20mph range AND with an Analyst system I could limit the amps for longer distance or turn it up if I need more power.

With the eZee system I pay a bit more money, but I'm limited to a 20A system. The 5305 with a 36-72v 48A controller and the CycleAnalyst gives me a very flexible system with the ability to increase amps for more power or voltage for more speed.

Hmm... it's looking like the Brute 5305 might be a winner....

Well, there isn't anything wrong with the 5305 if a high powered system is what you're after. While the eZee can accept more than a 20a controller with a switch out, it hasn't got the wiring to take extreme current like the Crystalyte can. Crystalyte motors have the most robust wiring of any hub motor i've seen. They will handle some seriously excessive current.

The 5305 is going to be more efficient in optimal conditions, but thats what the simulator represents. In true usage, the consistently higher RPMs of the geared motor translates to a higher real world eff. At a lower power output, you're going to get better value from the eZee, but as you have figured out, the 5305 has more high end potential. It all comes down to how much solar energy you're going to have at your disposal, and what your ultimate goal for the vehicle is, I suppose. The Crystalyte 5 series are certainly a choice pick for those looking for very high power potential.

I suppose one important factor would be finding out how much photovoltaic capacity you're going to have available as well.

As for the motor selection... I'd rather have more flexibility in my system and the ability to handle more power if I want it to, especially if it's not going to cost me any more money, which it appears it is not, it's actually about the same price for the higher powered crystalyte setup.

My solar capacity is yet to be determined. I'm going to build a small lockable "trunk" to replace the basket on the back of the bike. The lid of the trunk will hold the solar panels and the battery pack and other electronics will go inside the trunk.

With the 36v setup, I'll have 3 12v panels wired in series, if there's enough room I'll double up with 3 more in parallel. The question that remains is how big of panels I can fit on the trunk. I should be getting the bike itself within a week, then I can actually measure things out and get a better idea of what I'm dealing with.

I will of course put as much capacity as I can fit, but really, the solar part is just more of a passive charging system. I would like it to be able to charge the packs from dead to full in about a day. I figure if I can do that, I will have a noticeable extended life (range) on the pack. The best thing about the solar is that it's just there charging whenever the sun is out.

Any suggestions on solar panels to use? I am going to try to get these donated, but there's a chance I will have to buy them myself.

You know....at this point, what occurs to me, is that those type of trikes have hubs that are fixed to the drive axle.

You can't put a standard electric hub motor on the rear wheels, anyway.

Forgive the repeat if someone else already mentioned this.

I know that, that's why I'm getting the front wheel hub. It'll actually make it a 3 wheel drive with both electric and pedal power!

What I'm really hoping is that I can rig up a disc brake on the rear axle.

As for the motor selection... I'd rather have more flexibility in my system and the ability to handle more power if I want it to

Successful solar vehicles are highly optimized for efficiency. Permanent magnet motors lose efficiency at low power (I don't understand the details, but I've read that maximum efficiency is reached when the magnetic fields of the rotor and stator magnets are equal). I suspect you will get noticeably better efficiency with the eZee motor at the lower power level needed to make good use of solar power. The eZee is also significantly lighter in weight than Crystalyte 5 series.


My solar capacity is yet to be determined. I'm going to build a small lockable "trunk" to replace the basket on the back of the bike. The lid of the trunk will hold the solar panels and the battery pack and other electronics will go inside the trunk.

Have you done a back of the envelope calculation? Say you get 10 watts per square foot of solar panel and 4-6 effective hourse of use per day. That's about 50 Watt houts per day. I think you'll need a big trunk lid.


The best thing about the solar is that it's just there charging whenever the sun is out.
You know about the strict charging requirements of lithium batteries, right? Lithium batteries cannot be fully trickle charged. Best to contact your battery manufacturer to see how to adapt a solar charger, though limiting to 4.05 V/cell might be acceptable (4.20 is the normal max voltage for li-ion cells).
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Well, the eZee is only 20% lighter than the Crystalyte hub, and I can limit the amps to 20A on the Crystalyte with only 16% less torque off the line. According to the simulator, almost everything else is very close.

The eZee efficiency peaks between 15 and 20mph at about 74%, the Crystalyte peakes between 13 and 21mph and hits 80% efficiency.

AND>> The efficiency peak for the eZee happens when the motor is at full power, 500W. The Crystalyte hub reaches peak efficiency after peak power, when power use is actually reduced from 500W down to between 400W and 300W. Meaning that while cruising in the similar efficiency speeds, the Crystalyte actually requires less power then the eZee. That is becuase the gearing actually shifts more torque to the low end, sacrificing top end efficiency.

If I bump the Crystalyte up to 35A, I get slightly more torque than the eZee and even better efficiency, peaking at around 82%.

I know these are "ideal" figures, but I think it proves my point well enough. The eZee costs more than the crystalyte, but considering it is a much lower powered system, it doesn't appear to deliver that much of a benefit other than slightly higher torque off the line.

The extra few pounds of the Crysalyte hub are dwarfed by what I'm guessing will be a total vehicle and passenger weight (me) of over 300 pounds. With that much weight and excellent lithium batteries, I think it would be silly to limit myself to 20A motor system. I might very well need more power considering weight and the Crystalyte can provide it if needed.

Besides all that, "not making use" of solar because it is a high power system is a misnomer. Any power that can be harnessed from the sun for free is certainly not wasted, even on a high power system. Even if it has to sit in the sun longer to recharge, so what? If quick charging is an issue, I can always plug it in.

Again... with my specific batteries, you guys are not realizing that they are not LiPoly nor are they your average LiFePO4 cells. A123 cells are the most robust and forgivable batteries on the market. They have a maximum continuous discharge rating of 70A (Per parallel cell), and a maximum charging rate of 10A (per parallel cell). They are 3.3v nominal (3.6v peak charge) each and are very forgivable. You can even drain these batteries to 0v (although it's not recommended) and get them to charge back up with almost no noticeable effect in capacity. Cell capacity is 2.3Ah (6 parallel gives 13.8Ahr)

If there's a lithium battery out there that can take a solar trickle charge, these are the they!!

Here's the website: http://www.a123systems.com/
Here's the battery spec sheet: http://a123systems.textdriven.com/product/pdf/1/ANR26650M1_Datasheet_AUGUST_2008.pdf

My proposed batty pack will be 6 in parallel, 11 in series. This will give me a total of 36.2v/13.8Ahr and a max rated continuous discharge of 420A, max rated charge rate of 60A. Peak charge voltage will be 39.6v, but I won't be using the solar to do peak charging, only to help refill the batteries when they are below nominal voltage.

They are rated at a 120A max pulse discharge, meaning 6 in parallel could do a 10s pulse of 720A. Despite this rating, we failed to see how it was possible because the cell voltage would drop to about 1v under a 120A load due to internal resistance. We figured it's better to keep it under the continuous rating, about 60A or less for continuous discharge (6p = 360A).

These are quite possibly the best batteries for EV and LEV low and high power applications. One of the main reasons besides performance, safety! These cells do not explode like LiPo cells do. If they are extremely overloaded, they simply short out internally instead of combusting. Even puncturing them with a nail will not produce and explosion or any fire for that matter.

I am going to try to track down our documentation from the 200hp electric motorcycle project I worked on last semester. Me and a teammate actually drove out to Boulder Colorado right before finals and assembled 35 modules (a few more than we needed) of 4s8p 13.3v packs to be arranged in 128s8p for the motorcycle, that's a total of 1024 cells. These packs are in the process of being installed in the motorcycle right now and will be looking to set land speed records next summer.

Well, the eZee is only 20% lighter than the Crystalyte hub
Isn't the eZee motor around 7 pounds, and the Crystalyte 15? These are from memory, but I'm sure the difference is noticeable.


The eZee efficiency peaks between 15 and 20mph at about 74%, the Crystalyte peakes between 13 and 21mph and hits 80% efficiency.
Typical efficiency loss for planetary gears is about 3%, which should made up by the faster spinning motor. Something is wrong with that 74% efficiency number - either your simulation is wrong, or the eZee motor sucks.


Besides all that, "making use" of solar is a misnomer. Any power that can be harnessed from the sun for free is certainly not wasted, even on a high power system. Even if it has to sit in the sun longer to recharge, so what? If quick charging is an issue, I can always plug it in.
If you have access to the power grid for recharging, then putting the solar panel on your bike is counterproductive. You'll waste energy accelerating the panel's mass and overcoming its aerodynamic drag, while a fixed panel can be better oriented for much greater effectiveness.


You guys are not realizing that they are [A123 cells]
My bad. All you need is a voltage limiter.

Okay... The weight of the 5305 is 24 pounds including the rim and spokes.

The eZee motor itself weighs 8 pounds, maybe 10 pounds with the rim and spokes?

So I guess I was wrong about the 20% figure, thought I had read that in the eZee description. I guess I just don't care that much about 14 pounds when it comes to a much more powerful and robust motor that can be limited if I want long distance travel between charges.

I just had another idea... if I limited my pack to 10 in series, I could use extra DeWalt Packs to increase my capacity for long distance travel. The DeWalt packs have exactly 10 of my cells in series, which is actually only 33v nominal while they rate the packs as 36v which is the peak charge voltage.

That would make a good option... I wouldn't be surprised if people are already using just the DeWalt packs with like 4 to 8 of them in parallel. Of course that would be pretty pricey, I got my cells used for much much less... about $5 per cell.

If you have access to the power grid for recharging, then putting the solar panel on your bike is counterproductive. You'll waste energy accelerating the panel's mass and overcoming its aerodynamic drag, while a fixed panel can be better oriented for much greater effectiveness.



Hmm... damn, you may be right.. but really, those tiny 12v panels are not heavy at all and they would be laid flat on the top of the trunk and not adding to drag, and drag really isn't a huge factor under 20mph anyways. Rolling resistance is probably bigger with bad tires on. That's another thing I plan on addressing with some good street slicks.

I wish I could get my hands on a piece of that Nano-Solar thin film paneling. You can literally cut it to size and lay it flat on any surface, that would be perfect! Too bad they're sold out and probably won't be selling to consumers but through third party suppliers who won't have any until some time next summer.

Here's another comparison chart. Unfortunately it does not contain the 5 series, but there are 4 series on there.

http://www.cycle9.com/Products/HubMotorsNew_assets/hub-motor-compare.pdf

I don't believe that the simulator on ebikes.ca accurately reflects the differences between the motors. I would contact someone there for specific information. In our testing, our BMC motors consistently provide superior distance and output per watt over direct drive systems, I would expect similar results from eZee given their similarities. However, we've also dealt with the Crystalyte 5 series for a long time, and they are fine kits as well.

Really, I agree with Unime. I've seen solar trikes before, and the only design you're going to get good value out of is one that gives the most mechanical output for the least energy, because you're really not going to be able to carry a lot of energy production on the trike in a reasonable fashion and the thing will simply end up a fiasco if you're carrying extra weight, cost, and complexity, for little added benefit.

Given that you'd have a poor time dealing with the fickle alignment needs and heavier weight of mono/polycrystalline panels, i'd think that flexible amorphous solutions would be a good option as well, although it would be harder to custom build an array to conveniently deploy.

What fiasco? The only difference in this system with or without a solar system is the panels and a panel charge controller.

Again.. even if my system isn't the most efficient, any solar is better than none right?

I already stated that they will not contribute to drag and they weigh so little that they won't make much difference on total mass. I bet wearing a backpack with a few textbooks in it while I ride would have a bigger effect.

Yes and no on any solar being better than none.

Well, make a comparison to other options for instance.

Home charging?
The panels could be aligned for great efficiency, remain safer from damage or theft, keep the weight of the system lower and remove the potential nuisance of having an unwieldy 50+ watt panel structure, and so on. They could be fed to other devices within your household as needed as well, increasing their overall yield if they produce a surplus. The weight freed by the solar panels being removed could be taken up with increased battery capacity, making the trike travel further, as well.

The trike would then still be solar powered, but with additional benefits and tradeoffs.

Personally, if someone were to show me a solar powered vehicle that was only marginally boosted by the panels, yet came with the cost, complexity and vulnerability of such a setup, I wouldn't consider it worth it, no. To me, the solar would have to have enough influence on the system to make it worth its downsides, and a small boost wouldn't do it if I could simply get much better result with a home based system, or just buying my energy from someone like Bullfrog, for instance.

I think carrying the energy production capacity with you is great, but it has to be worth it over the other alternatives to be useful, and that means having a system capable of providing good output on its own.

I don't want to purchase a 50W system for my bike just to have it sit at home.

I think you're missing my point, I don't care if the panels put out much power. I certainly don't expect them to drive the motor at all. As I originally state, they are more of a passive charging system than an all out power source. A few small 12V panels won't cost much, won't weigh much and will not significantly increase the complexity of my project.

If nothing else, just think of it as a minor feature that will look cool and help supply energy, however little it does, while you're not riding it (ie: outside your house before you leave, while it's parked at work or school or wherever. You can't always plug in, but you can park in the sun....

I'm guessing I'll have about 4 to 8 square feet on top of the trunk, why not put solar panels on it???

There's tonz of these 5W 12V solar panels for charging vehicles and they're about 12x18 inches and pretty flat. Three of them side by side and I can supply 5W of free energy to my batteries. They're selling from $20 to $50 each, but I'm pretty sure I can get my local solar company to donate them.

Post up the pictures when you're done. I've run my 5305 on 48SLA volts and 74LiPoly and man, on the 74 volt Lipoly it is downright scary powerful! If it weren't for the measly current limitations of the controller, I can probably do 0-40 in about 5 seconds! My cells are 10,000 mah lipos rated at 10C continuous, 20C peak and I'm using 20s1p and sometimes 10s2p for longer runs. I'm presently using the 5303 with 10s2p - good balance of power and range and decent speed. Mine's for leisure only.

Probably one of the trickiest parts of this project is going to be building the trunk. I'm thinking of doing it out of composite fiberglass. That way I can have a big trunk without it weighing too much.

I'm familiar with composites, but I haven't actually done it. I'm good with auto-body work and I'm pretty sure I can tackle composites. It's just laminating layers of fabric with epoxy, can't be that difficult!

I will certainly post pics as I progress through the project. I'll probably start a new thread once I have decided on all my components and actually start putting it all together.

... I really need to look at the bike, wish it would get here already. I'm now rethinking my approach.

I was looking around and the only solar charge controller that will do 36v is either $75 from hong kong, or like $500 from some other company...

Perhaps you are right, maybe I should forgo the solar system and focus on something more useful like a proper quick charging system for around 10 to 30 minute charges.

I'm also considering going with a regular motor instead of the hub. If there was some good way to adapt a motor into the gearing of the bike, maybe add a few gears to the rear axle. If I can forget about the solar panels and making the trunk big enough, I should have enough time to work on a better system, not to mention it would be hundreds of dollars cheaper....

... ugh... I just really need to see the bike....

EDIT: scratch that... too much work. I did notice that they have a nifty brake shoe and drum set on the rear driveline and the ability to set it in "park". Don't think I should mess with that... damn hubs, why are there so few good geared hubs? It'd be nice if I could have some variety to choose from. The stinkin eZee is more expensive and less powerful... boo! I've heard too many people tell me that I will want the ability to power up, the eZee does not afford me that opption. At $1250 for the kit, you'd think it'd be more flexible.

HOT DIGGITY DAMN!!! I just realized that if I don't have the solar panels to worry about, I can just buy a motorcycle trunk to mount on the bike. They look really good and they lock, it's perfect!!

http://i.walmartimages.com/i/p/00/03/86/75/40/0003867540013_215X215.jpg
I don't need or want that much speed because this is a trike and I'm not sure how well it will handle over 20mph,That's a very poor EV candidate. Because of the elevated CoG, attempting speeds much over 10 mph will be foolish at best and likely get someone hurt - and 20 mph isn't even realistic. Optimum deltas should have 66% of the laden weight over the rear axle, and the optimum CoM location should be no higher than half the track's width. Any higher and the trike becomes susceptible to roll-overs.

Well, I personally don't think 20 is really that fast. It feels like crawling in a car and I know I get going faster than that on my mountain bike with no problem. Yes obviously you would need to slow down to take corners, on a trike you'd be stupid not to. But really, would you want to limit yourself to under 10mph, even on long straight treks?? Heck no! Other people have electric trikes like this one and they say they love it.

I don't want one of those crazy looking low riding trikes with 16 inch wheels. I want a cruiser. How much do those specialized trikes cost? $1200??

I got this bike because it was cheap and has an aluminum frame, room for a cargo/electronics rear trunk, good brakes and sturdy construction. I got it for $210 with tax, but every review I've read has raved about how well this bike is built and how enjoyable it is to ride, as I said, a few of them even mentioned putting a front hub motor on it and that it was fine.

The bike is only as dangerous as the operator is careless... you could roll or wreck on any bike, motorized or not.

I know I get going faster than that on my mountain bike with no problem.The dynamics of single track vehicles (i.e MTBs and road bikes) are completely different from trikes, so direct comparisons are not possible. http://www.jetrike.com/why-does-tilting-matter.html


The bike is only as dangerous as the operator is careless... And pushing the trike's speed outside its designed envelope is indeed careless. And the first time you attempt an evasive maneuver at speed, (to avoid collision with a dog, for example), you'll quickly discover its limitations.

To be clear, I'm not trying to discourage your project. My only intent (as a professional designer/builder), is help you avoid skin loss.. or worse.

So what... how fast do you think is safe on a trike like this? I'm sure they're geared to go at least 10mph without much effort and no electric assist.

What about the 4011 Crystalyte motor? It has a top speed of about 15 with a 36V battery in it. Only problem is it doesn't have much torque for lugging around a 300+ pound load.

Or I can drop my voltage lower to get slower speeds. I guess 10mph isn't too bad just for cruising around town.

I guess maybe a geared hub would be better, more torque less top end. Are there any other geared hubs to compare to the eZee? I just don't like the several hundred dollars more I'd have to pay for the eZee over a more powerful system. Doesn't seem right to me. It has a smaller motor and a relatively low current limit. What am I paying for?? Planetary gears??

http://www.endless-sphere.com/forums/viewforum.php?f=21

Where did you manage to find those batteries at $5 each?

this is a sincere question, I'm not trying to give a hard time...

What part of you project qualifies this as a suitable engineering project? ie what kind of features and technology will bring this bike out of the ranks of hobbyist, and into the ranks of academia?

rgds
Tyler

Papa: What exactly are you pointing at? The eBike forum @ endless sphere??

James: We got the cells used from a hybrid company in Colorado. They had used them in some experimental packs used to power remote communication stations (why a hybrid company is doing that, I don't know) We purchased over 1200 cells total at $5 each. They were in questionable condition when we got them, some of the sets were drained to just above zero volts. We had the majority of them tested in California and the results came back good, the cells had still maintained their capacity and load abilities even though they had been improperly cared for.

SeizeTech: Well initially the engineering aspect was to tie together a solar charging system with an electric bike, but apparently in order to make that efficient you have to make everything else about the bike low weight, low rolling resistance ect. I don't have the time or money to do that, so I guess I'm dropping the solar in favor of designing a quick-charge system for the A123 batteries, hopefully something that will give me a full charge in 10 to 30 minutes.

I realize this isn't an extraordinary project by engineering standards, but I'm also only at the BS level of engineering, not a masters. Our school has a small department which has recently lost most of it's funding, as well as several of our few faculty members which were replaced by two new ones. Our new department chair last year had us working on an airplane project (mechanical and composite work), 200hp electric motorcycle project, and facilities planning for a building our department was taking over. The chair is no longer with us this semester and our department is somewhat in dissaray, so it's up to us to find something useful to do.

My program is Integrated Engineering, so basically just general engineering with no real emphasis on anything in particular. Some other projects my classmates are working on include working on a rotary engine for use in a small airplane we have, designing roadbase for a local civil firm, designing a programable climbing wall with lights to mark paths, and another pair is doing a solar home design (I'll be surprised if they really get anywhere with this one).

From an engineering standpoint, my project will most likely involve comparison of different drive systems and components as well as the application of the advanced lithium technology that A123 offers. I would think a quick charge system for these cells would be of interest to anyone who's tired of waiting 4 to 10 hours to recharge their bike.

Of course there is much to be analysed and calculated formally, right now I'm just trying to get together my project proposal, which is due today. I spent most of the semester waiting to hear from one of my professors about funding for a project he was going to have me work on (and get paid for). The project was analysing the blade of a wind turbine using Fluent, a dynamic fluid analysis program, to test and modify the blade profile to get the best performance. Unfortunately I found out a few weeks ago that the funding did not go through (damn recession) and so now I have to come up with a senior project that I can do in one semester.

The saddest part is that I am really interested in electronics and alternative energies, but quite honestly I feel that our program failed us in properly teaching electronics in favor of cramming circuits, electronics and mechatronics into single semester classes taught by professors who either did not specialize in electronics or were just plain unprepared to teach the courses.

Designing the charging unit will be a major challenge for me, but I hope that it will be a means of strengthening my understanding of electronics.

Also, this project may serve to promote electric vehicles and alternative energies in general. I am hopefully going to be getting a job working for a local solar & wind power company in January and was wanting to incorporate solar, but apparently with my proposed vehicle solar just isn't viable.

I would love to actually design my own bike from scratch, but I have very limited or no access to the needed fabrication systems like pipe benders and other machining equipment, not to mention the money and enourmous amount of time it would take to do it all from scratch. So, I'm limited to affordable canned systems for the majority of my project.

Not ground-breaking work I know... but what can I do??

As eBike enthusiasts, is there anything else that you think would be a useful project that can fit my constraints??

I got my MPPT controller from John Drake Services - paid $104 for it, nice, small package. John has a wide range of products available, shipped promptly, personal note of thanks written on invoice.

http://www.solarseller.com/solar_converters_mppt_charge_controllers_maximum_power_point_tracking.htm

For a set of panels like I have, check out -

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=90599

Comes with 12v controller which outputs multiple voltages, 12v lights, collapsable rack for panels, wires.

FWIW - I have my front hubmotor for sale at -

http://www.bentrideronline.com/messageboard/showthread.php?t=45376

And using the trike you spec'ed should work just as long as you don't allow yourself to get overly seduced by speed and testosterone. Brakes are meant for 'geezer riders', a fact which I recognize all too well, as most on this board will consider me to be in that category. My 36v WE hub will take you easily up to 15 mph without pedaling, and up to 20 or more with exhuberant pedaling, and being unable to stop can really hurt. So, slow for corners, no sudden turns, no 'stupid' tricks or risks. If you don't know the definition of a stupid risk - watch this video!

http://www.youtube.com/watch?v=5xn-XlsTcck

She's young, cute, blonde and either very . . . we'll let you decide what she is.

While I think the A123 batteries are best available, you had better not run them down to 0 volts. It is the one way to kill these batteries fast. Check out endless sphere for details.
Have you taken this trike out for a ride at 25 mph? Better be wearing a metal suit.

Papa: What exactly are you pointing at? The eBike forum @ endless sphere?? Yes. Enough EV talent at ES to polish your BS. Many of the guys there are sharp as a tack.

Yes. Enough EV talent at ES to polish your BS. Many of the guys there are sharp as a tack.

By BS you mean....? Bachelors of Science right? ;) I try not to indulge too much in the other meaning of it, but hey, I guess sometimes it happens huh?

I'll check it out and post a reformulated problem statement as soon as I get my proposal typed up.

I think Tourzrick might be onto something with the solar trailer idea. He gets 45W from his panels and that's certainly enough to extend the range and recharge during stops. Especially if you pair that with an efficient hub around 200W, which would mean the panels could supply almost a quarter of the energy. If I could only find a good geared hub that didn't cost so much. The eZee puts my power system costs alone up around $1000 not including solar panel system and battery charging system.

Perhaps that will be part of my proposal, to determine the best way to incorporate a solar charging system with an LEV in a meaningful manner and create some way of quantifying the advantages or disadvantages of using different system components to justify on-board solar. I loath the tedious data collection process, but I know it's the only way to show proof of principle...

By BS you mean....? Bachelors of Science right? ;) I try not to indulge too much in the other meaning of it, but hey, I guess sometimes it happens huh?

I'll check it out and post a reformulated problem statement as soon as I get my proposal typed up.

I think Tourzrick might be onto something with the solar trailer idea. He gets 45W from his panels and that's certainly enough to extend the range and recharge during stops. Especially if you pair that with an efficient hub around 200W, which would mean the panels could supply almost a quarter of the energy. If I could only find a good geared hub that didn't cost so much. The eZee puts my power system costs alone up around $1000 not including solar panel system and battery charging system.

Perhaps that will be part of my proposal, to determine the best way to incorporate a solar charging system with an LEV in a meaningful manner and create some way of quantifying the advantages or disadvantages of using different system components to justify on-board solar. I loath the tedious data collection process, but I know it's the only way to show proof of principle...


best of wishes for your project. I will be looking forward to reading any updates that you have time to show us.

some possible tips:
- considering purchasing a Cycle Analyst for data collection and testing
- consider tying everything to a microcontroller, then add as much intelligence to it as possible.

Also, check out battery university . com. I beleive that they dont reccomend quick charging a lithium battery because the balancing phase at the end of the charge cycle ends up taking longer, hence, there is no advantage if you are trying to preserve the long term life of the batteries. ie quick charging without balancing will be hard on them

have you considered regenerative braking with a supercap to take the charge?then slowly transfering the charge to the batteries? most regerative braking systems create too much current, too fast, so you ussually have to burn some of it up on a heat grid because its hard on the battery to charge at high current.

By BS you mean....? Bachelors of Science right? ;) Bull feces wasn't exactly what I had in mind when I typed, but now that you mention it....:D

Hi Simplecj,

My final year project is also designing an E-bike. Last year one of the people on my course designed a mechanical regenerative braking system for a trike, and used a direct drive motor, not a hub motor. These can be typically 95%+ efficient, wheras most hubs are 80% efficient.

Another idea for your project could be to do as you suggest, design a large charging device which could incorporate solar panels. However, the engineering feat could be that you design it for the commercial market, with the intention of selling these 'solar charging stations' to various service stations on the road networks. They can then put these next to their petrol pumps and voila, you have a network of possible e-bike routes where you can charge up, (for a small fee).

The technical aspects are pretty simple too. You can incorporate a couple of super capacitors to hold the charge, from the solar panels, and then quick dump charge any bikes that get connected. Any excess supply, once the caps are full, could be used to power the flashy lights advertising that this super cool service station can provide a full charge to your ebike in 10 minutes. Although you will have to design multiple outputs, for those who dont own those amazing lithium batteries =(

The best part is that the cost doesn't matter too much, as it won't be for home use, it would be for commercial. You could then justify it saying that one day, electric cars can use the same thing, so its a beneficial investment heh.

Good luck!

nobody is going to be allowed to provide a full charge to my lithium ion batteries in 10 minutes not matter how safe they say it is.

I've got over $400 into my batteries, and I don't want to see them all cooked and expanded from a 10 minute charge.

http://www.endless-sphere.com/forums/viewtopic.php?f=14&t=4908&st=0&sk=t&sd=a&hilit=yard+works&start=285

check out this thread, it has pictures of how a battery can overheat and expand when you charge it too agressively.

Are you guys sure you are engineering students? if so, I suggest that you stop learning the vector math and calculus, and spend more time reading sites like www.batteryuniversity.com (http://www.batteryuniversity.com)