ElectricMotorcycleForum.com
Tech => Home Brew => Topic started by: TurnNBurn on June 05, 2012, 12:32:33 AM
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Hello all! I just picked up a Honda CBR that was in great condition (engine is in good condition too!) Anyways, I'm looking to sell the mechanical parts and build it into an EV bike. I have a few questions.
I've been doing some research, and I see Electricmotorsports.com seems to be a good place to buy parts. I have questions about motors. First off, what's the difference between a brushless permanent and brush type motor?
Second, I'm not a speed freak, but I'm in Vegas and highway travel is almost a must because of where I'm located. What specs should I be looking for to get me up to 75mph wih a range of about 45 miles? Do I need to be concerned with horsepower ratings at all?
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Brushless require more complicated motor controllers, but are lower maintenance motors. I won't comment on the power/weight/cost of each, cos you'll be finding that out more accurately when you have a look around for the best motor for you.
75mph, is, at a guess up between 15-20kw. So you'll have to get a motor that is rated for this continuously, not just peak, the peak rating is useful when accelerating, so make sure that is 30kw or more, and that your controller is rated for the peak too. You'll also have to ensure you battery pack is large enough to output that power. For pack size, say 20kw for 40mins (to get the range at 75mph + a bit extra for acceleration), is 13kwHr.
The big questions are, is how much are you looking to spend? How mechanically proficient are you? How electrically proficient are you?
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The big questions are, is how much are you looking to spend? How mechanically proficient are you? How electrically proficient are you?
I'm quite proficient mechanically, but not electrically. I've pulled a few car engines and transmissions and have done a lot of work on cars. This will be my first motorcycle job. To start I didn't want to reach the 75 MPH/45 mile goal, I wanted to start with a motor and powerplant that would potentially allow me to upgrade the batteried later on down the line.
Cost is always a factor, but I'm not buying the parts all at once. I wanted this to be a weekend project thing that I can buy parts for monthly and keep adding on to it. I just need to know what I'm looking for. Since the bike was in such great shape, the engine is in great shape and I was going to rebuild that and possibly sell it. I'm also tempted to reinstall the gas engine once it's rebuilt, but I'd really like to make the EV conversion work.
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what kind of budget?
Do you want regenerative braking?
what top speed do you need (not just 75mph, you'd likely want more)?
What range at 75mph? what range at 45mph?
Can you reduce the range requirement by charging at work or something?
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My "drive" to work is only about 5 minutes, and I usually walk to work. But with an electric bike I would probably ride it to and from, but I wouldn't be able to charge it at work. So that's not an issue.
Around town everything is out on the far side and usually requires sustained speeds of 45 mph. There's usually 2 ways to get to where I like to go. I can drive for 30 minutes at 45mph or take the highway at 75mph and be there in 10-15 minutes.
I don't think I'd want regnerative braking. I haven't looked into that at all yet.
As for the budget, I didn't want to dump a whole lot of money into it since it was just a fun project. I was hoping I could sell the engine and other miscelaneous parts from the bike and make back some money to increase the budget. But at this point I just want to weight the costs for all of my options.
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regen = engine braking.... so consider it. You'd have to use brushless (AC or BLDC) or use a brushed PM motor with a regen controller. If it's not a huge thing, get a 6.7" forklift motor with gobs of torque. I wouldn't really mess with the brushed or BLDC Mars unless you get the double stack BLDC. You need a bit of power to get to 75mph. You will likely also need a higher voltage than 72V.... like 96V.
Basically for a range of 40 miles, you could do it with lead, but you'll get less and less out of the pack over the next year. I'd stick with lifepo4. You'd also need a really large and heavy pack. For a 40 mile range, and lets assume ~100wh/mile, you'd need about 4kwh of useable energy. With lead, you'd need over 5kwh. With lifepo4 you might need right around 4kwh. Going with GBS system (with charger and BMS with LCD) you're right around $3200 or just batteries for ~$2000. Going with CALB, you're at about $1700 without BMS or charger.
Motor and controller is going to be in the 1500-3000 dollar range, depending on what you get. You could go with AC Induction like I did, but that'd set you back a bit over $3k. You could do a BLDC/PMAC motor like the mars double stack for ~$850 then a matching controller with enough power to get you to 75-80mph for another $800 for a small controller or $1400 for a higher power one. Charger is going to be at least $500 new. Then chain, sprocket (you'll need a new rear sprocket and some front sprockets), cables, fuses, contactor, DC-DC converter for your 12V stuff (another $100-200).
So it's not cheap, but it can be done for under $4k if you really scrounge for stuff and bargain hunt. My first version of my bike used a surplus $250 forklift motor and a cheap cheap brushed controller and some used UPS batteries and got about 65mph max and maybe 15 miles at 45mph or less and cost me under $1000 without the cost of the bike.
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Thans for that info. That helps a lot. I'm looking to start small, maybe with basics and build up from there. So if that means getting a motor that only gets me to 45mph, so be it. In the future I'll upgrade. Right now I'm looking on craigslist for forklift parts and golf carts. I'm not finding much. You'd think vegas would have anything you could want. But mechanical bits are scarce here it seems.
One quick question about the brakes. Can't I keep the stock brakes on it, or do they require the engine to be running in order to be used? I'm in the process of stripping the bike and want to know if I should leave these on or take them off.
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Don't use a golf cart motor. They're usually meant to be coupled to a differential and don't have the shaft end bearing/plate and have a splined female shaft.... not great for a motorcycle unless you want lots of work. Use a forklift motor or something surplus, maybe a mars. Look secondhand if you can. Check out elmoto.net and evtradinpost.com
Stock brakes are fine. No requirement for engine braking usually. Most are independant hydraulic brakelines. Keep all brake and electrical wiring harness. sell/throw away the engine/exhaust keep the radiator or oil cooler in case you want water cooling later.... keep the rear sprocket for now.
let me know if you need anything, I've worked with a ton of people on getting them parts and I work with most budgets. www.emf-power.com (http://www.emf-power.com)
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Don't use a golf cart motor. They're usually meant to be coupled to a differential and don't have the shaft end bearing/plate and have a splined female shaft.... not great for a motorcycle unless you want lots of work. Use a forklift motor or something surplus, maybe a mars. Look secondhand if you can. Check out elmoto.net and evtradinpost.com
Stock brakes are fine. No requirement for engine braking usually. Most are independant hydraulic brakelines. Keep all brake and electrical wiring harness. sell/throw away the engine/exhaust keep the radiator or oil cooler in case you want water cooling later.... keep the rear sprocket for now.
let me know if you need anything, I've worked with a ton of people on getting them parts and I work with most budgets. www.emf-power.com (http://www.emf-power.com)
That's good to know. I had the radiator in the "scrap to sell" box. Why would the radiator be something to keep as opposed to making some sort of air cooled system? Since it's a sports bike and I have all of the fairings, wouldn't air cooled be the way to go? Also, with keeping the radiator wouldn't I need some sort of fluid pump to circulate the coolant?
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The big questions are, is how much are you looking to spend? How mechanically proficient are you? How electrically proficient are you?
I'm quite proficient mechanically, but not electrically. I've pulled a few car engines and transmissions and have done a lot of work on cars. This will be my first motorcycle job. To start I didn't want to reach the 75 MPH/45 mile goal, I wanted to start with a motor and powerplant that would potentially allow me to upgrade the batteried later on down the line.
Cost is always a factor, but I'm not buying the parts all at once. I wanted this to be a weekend project thing that I can buy parts for monthly and keep adding on to it. I just need to know what I'm looking for. Since the bike was in such great shape, the engine is in great shape and I was going to rebuild that and possibly sell it. I'm also tempted to reinstall the gas engine once it's rebuilt, but I'd really like to make the EV conversion work.
Thats the better way to be, the electrical side of things is a bit simpler than the mechanical in these builds.
Be wary of feature creep, it generally costs more in time and money than just doing it properly to begin with. If you're sure you want a bike with high spec speed and range, then do the budget for that, and go for it if you can afford it. Starting with cheap parts may sound good in theory, but chances are the newer and better stuff you get later won't bolt straight in, and will require almost as much work again, as the cheap part conversion did.
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That's good to know. I had the radiator in the "scrap to sell" box. Why would the radiator be something to keep as opposed to making some sort of air cooled system? Since it's a sports bike and I have all of the fairings, wouldn't air cooled be the way to go? Also, with keeping the radiator wouldn't I need some sort of fluid pump to circulate the coolant?
I'm just saying keep one of them for now. Air cooled motor is just fine (most motors you find will all be air cooled). I'm saying keep either that or the oil cooler if you want to water cool the controller later. Usually the controllers are tucked inside the fairings and don't get great flow. Right now I'm just using a custom finned heatsink, but I have the option to use a water cooled plate that I had made if the controller gets too hot. You may not need it at all, and 90% of builds don't.... but it doesn't hurt to save it now.
And I agree with Bogan. See if you can afford what you want, up front, even it it means saving a while. Buying cheap or small now, then upgrading is good if you can resell the stuff later... but things like batteries don't resell well, and motors wear and aren't worth as much later. You'll lose money in the end. It's what I did, and I managed to come out as a loss. batteries were a total loss when upgrading, motor I broke even, controller was returned to the place I borrowed it from.... but I lost money in the battery frame material/labor and the motor mount material/labor, charger, cables, fuses, contactor and chain.
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Alright, sounds like good advice I shoud adhere to. I think I'll just stockpile money and get the desired parts first instead of upgrading.
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Get batteries LAST, so you get some that are new and haven't been sitting while you do stuff.
Get motor/controller first and get it fit inside. When you get that done, start looking into batteries..... more might come on the market in the meantime.
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Good point on the batteries frodus, I'd add to that you still want to design with specific batteries in mind, to ensure you will have space for them and not end up with a hodge-podge of batteries stuck all over the show.
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That was my overall plan. I was going to choose the batteries ahead of time so I know how much juice I'll have for distance, but I wasn't going to purchase them until I was almost done. At that time I figured maybe battery technology would have advanced enough to make them smaller and more efficient.
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Do any of you know anything about solar charging? I was thinking of getting a cargo box to cary a portable solar charger. How long do you think it'd take to charge 3 or 4 batteries with a solar charger? I think thinking about getting a large flexible panel that I could sort of drap over the sides of the bike like a cover.
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At a guess, 100W of solar if you get good panels. approx 10kwhr of batteries, is 100 hours for a full charge, or 1% charge every hour.
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Wow. Now I know why solar panels never really caught on. That's no bueno. 6 hours for 6%. That'll get me to the first stop sign. Do you guys know of any other charging methods I haven't considered or have any odball ideas?
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Maybe a receptacle at wherever you are?
I mean, they're literally everywhere you go.
Nothing really mobile other than a generator running on propane or natural gas rather than gasoline/petrol..... but receptacles are the best options.
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Maybe a receptacle at wherever you are?
I mean, they're literally everywhere you go.
Not here in vegas. Shocking, actually, since solar energy is so abundant here.
Another question that's been on my mind. I saw a youtube video of an EV bike that had 2 motors. What advantage would having 2 motors give? It seems like a waste. Wouldn't it draw twice the power without giving any extra benefit? Or would the 2 motors ease up the load and require less energy?
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Found some information here: http://www.bikeforums.net/archive/index.php/t-694962.html (http://www.bikeforums.net/archive/index.php/t-694962.html)
Sounds like a challenge that I would like to accept, especially considering it will increase range.
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2 motors splits the power between two motors.... which is better for motor efficiency since the resistive losses would be less than running that motor at twice the amps to get the same power. Say you have one motor and use 100A and compare to 2 motors using 50A each. It's more efficient at the motor due to less loss due to heat. That much is true.
Some things to consider though. 2 motors is a bit of extra weight. And depending on if it's BLDC or AC, you need 2 controllers. And depending on how you couple them together, you might have mechanical losses associated. If you use PM or series wound motors and them in series, it doesn't matter, you still have resistive losses the same as a single motor, it's just running at half the voltage. If the PM or series motors are in parallel, the current is divided and losses go down..... but there's an issue with getting the motors perfectly tuned. If one is just barely built differently and has different coil resistance, the motor with the least resistance gets more current. more current, more heat. More heat, more resistance.... then the other one starts to use more, and you end up creating more heat.
With a sufficiently sized single motor that is built to handle the amps, it's a much simpler system, cheaper, lighter, smaller. Keeping the motor cool will do quite a bit for efficiency.
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If you're interested....I think I'll have a new AC15 motor with warranty (or AC20 if you give me a heads up), but with a new out of warranty 1238-6501 controller. This is an AC setup with regen.
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If you're interested....I think I'll have a new AC15 motor with warranty (or AC20 if you give me a heads up), but with a new out of warranty 1238-6501 controller. This is an AC setup with regen.
I havent begun researching motors enough yet i dont know much about the ac15 or ac20. What motors would you guys would recommend for the top speeds i want to achieve with the distance im looking for?
im building a parts list one item at a time. im looking at motor for the speed and efficiency i want, a controller that is compatible and efficient, and batteries to last. Where should i begin researching each and what would you guys recommend for each part?
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Any recommendations for motors and controllers?
Is there any interest in me getting pics? I already have the bike stripped and about the be stripped, primed, and repainted. I'm about to get a list of electrical and mechanical parts I need to begin assembling.
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I'm looking at brushless motors, two of them being the PMAC-SS (ME0201014201) which is rated at 19HP. I'm also looking at the PMAC-DS (ME0913) which is rated at 40HP. I have 2 controllers picked out if I go with these motors, but I'd like to ask my next question first.
What about brushes versus brushless motors? What are the benefits of each and which should I be looking at for the speeds and distances I need?
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What Controllers do you have matched for each motor respectively? I'd still recommend an AC15 or AC20 for your application. Of your choices, I'd only choose the DS. 19HP might be a bit on the small side for your bike. It's not a tiny bike and you want some fair speeds out of it. The PMAC-SS might take you a bit to get to 75mph... if at all. The DS shouldn't have any issues.
Also, it's not a brushed versus brushless thing, it's power. A sufficiently sized brushed motor could accomplish the same job.
Pro's of Brushed:
Easy to get motors
Less complex (cheaper) controllers
easy to tune the controller
Cons:
Brush maintenance
Slightly less efficiency
Pros of Brushless:
Only bearing maintenance
More efficient (but not always)
More power dense (but not always)
Cons:
More complex (expensive)controller
Harder to tune the controller to match the motor
More expensive/harder to find motors
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For the controllers on the brushless motors I was looking at the Sevcon Gen4 72-80V (180A) or the 72-80V (350A). The price difference is $400 between the two.
For the Brushed motors I was looking at the EMC-RT200 at 38HP and the EMC-R LS (ME1004) at 21HP. Obviously I'm going to want the more HP, but now the question is....brushless or brushed. The EMC RT-200 or the PMAC-DS. The prices on them are almost the same.
At this point it's looking like the PMAC-DS with the Sevcon Gen4 72-80V. But what amp? Are there better controllers to be had for this motor?
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Do a quick calculation.... what is (lets say 72V pack voltage) 72V * 350A? it's about 34HP.... but you won't get that out of the controller. 350A is motor side. 72V is battery side. You'll never see 350A in the battery side. You'll get 350A on motor side, but not at 72V.... it's modulated. Let’s assume you CAN get 350A battery side.... that means your batteries need to be able to supply that peak current. Let’s say they're 60Ah CALB cells... that's about 6C, which is OK for pulse discharges, but the sag will be pronounced (something like 2.8V or so).
So a 24-cell pack of 3.2V nominal cells will be 76.8V resting, but 67.2V under load..... so 67.2V * 350A is 23520W, or 31.5HP. The batteries and controller are the bottleneck. If you get batteries that don't sag as much, and you may help that, but not much.
Next:
You’ll absolutely want to get the motor AND controller as a package from someone who sells BOTH as a package. Otherwise you will need to purchase or rent a programmer and set it up yourself, which is not an easy task for many. If this is your first, just get it as a working set before you start the project.
Brushed is much easier to configure. If you can get a decent sized brushed motor and match it with a good Alltrax, Curtis or Kelly, then you’re un business.
If you want something you know works, and puts out the kind of power you want, I have an AC15 motor AND controller that I’d be willing to sell for way under what they go for brand new.
Sevcon Gen 4 350A 72V is : ~$925
ME0913: ~$825
Rental: Unknown if you can even rent it, otherwise it’s ~$900
Total: $1750 without rental/programmer
AC15 motor and 1238-6501 controller: $1900 and I’ll throw in one free rental of a programmer IF you even need it (2 weeks, you pay shipping to/from). It’s a well proven package that most of the online suppliers sell. Not trying to dissuade you, just be honest about what you need to get it working. I just happen to have one, slightly used for a development project that didn’t pan out. Controller is new, motor is only slightly used.
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AC15 motor and 1238-6501 controller: $1900 and I’ll throw in one free rental of a programmer IF you even need it (2 weeks, you pay shipping to/from). It’s a well proven package that most of the online suppliers sell. Not trying to dissuade you, just be honest about what you need to get it working. I just happen to have one, slightly used for a development project that didn’t pan out. Controller is new, motor is only slightly used.
I did find a few retailers that had package deals and they had as an option a few controllers to pick from. I'd definitely take you up on that offer, but right now I'm just putting together my shopping list and hopefully in a few weeks I'll be able to buy the parts. If they're available in a few weeks, I'll surely hit you up.
I'm trying to start selling the CBR parts (engine, exhaust, radiator, etc...) on craigslist. Those funds will go to my motor setup.
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Let me know, I haven't advertised it yet and am not in a huge hurry to get rid of it.
Where are you located?
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Let me know, I haven't advertised it yet and am not in a huge hurry to get rid of it.
Where are you located?
I'm in Las Vegas.
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So shipping won't be that much....
let me know, It's a LITTLE flexible, but not a ton.... I just want to see this particular motor in another motorcycle.
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I have a question I should have asked when I was stripping down the bike. What should I do about the wiring harness? I've been keeping it so I can use the turn signals, but would you guys recommend selling it and just wiring my own signals? The problem is, I've never wired something like turn signals before. I've installed custom off-road lights on my truck before, but that was a simple on/off switch.
I kept the motorcycle grips with the start switch, turn signal switches, and everything else. What should I keep and what should I scrap?
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Keep everything electrical except the coils, starter relay, starter, etc.
Keep the wiring harness for now, you may use it and you don't want to buy later. Just keep all the handlebar controls and switches and get rid of the rest (anything that has to do with the engine).
If there's a specific part you're not sure about, just ask.
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Alrighty. I'm keeping the harness. The only reason I contemplated selling it was because it's so dirty that I can't tell which color wires went to which device. And now that everything is apart I don't think I can just find the connecting device at the other end. I also have no tail light turn signals with this bike.