I'm listening, and have a question for those of you who have firm grasp of physics. Is a lightweight, reasonably powerful EV actually possible, or will it always be one or the other? Even using the latest, most expensive, technology available I always come up with an obese vehicle (on paper) - or one that won't get out of it's own way.
Have you looked at the Tesla roadster information? 0-60 less than 4 seconds, 120 top speed, 244 miles range, 2723 lbs.
has any one tried to build a ultra high voltage low amerage system i think that 500 volt or 1000 even would be great then you can get the watts you need with low amps it is just a thought dont know of the windings on the on the motor would be massive may bee .What about permanet magnets motors that are brushless
[This message has been edited by engine man (edited 01-18-2009).]
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09:50 AM
JRP3 Member
Posts: 318 From: Central NY State Registered: Jan 2009
The AC Propulsion setup goes to 450 volts I think, Tesla around 400 maybe. High voltage means more batteries of course. Tesla uses 6831 laptop sized cells.
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09:57 AM
toddshotrods Member
Posts: 1177 From: Columbus, OH, USA Registered: Aug 2004
Originally posted by JRP3: Have you looked at the Tesla roadster information? 0-60 less than 4 seconds, 120 top speed, 244 miles range, 2723 lbs.
Yes, and I saw the confirmation of it in Road and Track.com. I also took a really good look at the White Zombie Datsun, after you posted the video link. The numbers are nice, but when taken in context they don't make sense - for me. In the interest of proving the validity and potential of Ev's, for EV diehards, they are great milestones; bragging rights. For a person like me, looking to incorporate the technology into a project or two for marketing purposes the end doesn't justify the means. In other words, if I spent the same amount of money and time building an ICE-based vehicle I would get a LOT more bang for the buck; in performance numbers, in "wow factor", in longevity.
What I am trying to determine is where the technology is going to see if I should be working towards it. I would be willing to slow one of my current projects down to incorporate the technology, IF there is going to be some substantial progress in the near future. If not I might as well start looking at other alternatives.
Take my street rod for instance. If I keep going with it as an ICE-based project, and went with something like an LS7 in the final version, I would have a 1200lb vehicle with nearly 600hp! I don't even need to elaborate on the possibilities such a vehicle would offfer as a marketing tool. If I convert it to EV, I pick up a lot of marketing possibilities I really like (different, futuristic, technologically advanced, etc.), but the base and performance numbers will sufffer severely. If at some point the vehicle can't deliver on its promise it will in the end be, at the least, a bad investment; at the worst, it could be a permanent mark on my professional image.
Since we're on PFF discussing this, the prime example of this is the Fiero. Even though we all know it's a great little car, Pontiac destroyed its image by making a few simple mistakes along the way. It's hard to shed a tarnished image. I don't feel this is really off-topic because in developing any advanced propulsion this has to be taken into account. If there is some concrete reason (e.g. the laws of physics) that EV's won't deliver on the promise everyone invloved in the movement is signing its death certificate - again. You have to figure out what it really CAN do and promote the heck out of that. Any unsubstantiated claims will come back to bite you in the backside. That's why I support promoting and developing the top few technologies. If the whole alternative energy movement ends up being summed up as "hype", government and big business will revert back to fossil fuels and not worry about it again until the threat of running out comes up again. We've been there, done that...
[This message has been edited by toddshotrods (edited 01-18-2009).]
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10:30 AM
JRP3 Member
Posts: 318 From: Central NY State Registered: Jan 2009
Many of the limitations of the classic commutator DC motor are due to the need for brushes to press against the commutator. This creates friction. At higher speeds, brushes have increasing difficulty in maintaining contact. Brushes may bounce off the irregularities in the commutator surface, creating sparks. (Sparks are also created inevitably by the brushes making and breaking circuits through the rotor coils as the brushes cross the insulating gaps between commutator sections. Depending on the commutator design, this may include the brushes shorting together adjacent sections--and hence coil ends--momentarily while crossing the gaps. Furthermore, the inductance of the rotor coils causes the voltage across each to rise when its circuit is opened, increasing the sparking of the brushes.) This sparking limits the maximum speed of the machine, as too-rapid sparking will overheat, erode, or even melt the commutator. The current density per unit area of the brushes, in combination with their resistivity, limits the output of the motor. The making and breaking of electric contact also causes electrical noise, and the sparks additionally cause RFI.
One of the main differences is that much less rotor heat is generated with the DC brushless drive. Rotor cooling is easier and peak point efficiency is generally higher for this drive. The DC brushless drive can also operate at unity power factor, whereas the best power factor for the induction drive is about 85 percent. This means that the peak point energy efficiency for a DC brushless drive will typically be a few percentage points higher than for an induction drive.
In an ideal brushless drive, the strength of the magnetic field produced by the permanent magnets would be adjustable. When maximum torque is required, especially at low speeds, the magnetic field strength (B) should be maximum – so that inverter and motor currents are maintained at their lowest possible values. This minimizes the I² R (current² resistance) losses and thereby optimizes efficiency. Likewise, when torque levels are low, the B field should be reduced such that eddy and hysteresis losses due to B are also reduced. Ideally, B should be adjusted such that the sum of the eddy, hysteresis, and I² losses is minimized. Unfortunately, there is no easy way of changing B with permanent magnets.
In contrast, induction machines have no magnets and B fields are “adjustable,” since B is proportionate to V/f (voltage to frequency). This means that at light loads the inverter can reduce voltage such that magnetic losses are reduced and efficiency is maximized. Thus, the induction machine when operated with a smart inverter has an advantage over a DC brushless machine – magnetic and conduction losses can be traded such that efficiency is optimized. This advantage becomes increasingly important as performance is increased. With DC brushless, as machine size grows, the magnetic losses increase proportionately and part load efficiency drops. With induction, as machine size grows, losses do not necessarily grow. Thus, induction drives may be the favored approach where high-performance is desired; peak efficiency will be a little less than with DC brushless, but average efficiency may actually be better.
Originally posted by toddshotrods:Even using the latest, most expensive, technology available I always come up with an obese vehicle (on paper) - or one that won't get out of it's own way.
This is what I was responding to. Obviously using the latest and greatest you can build a killer vehicle. That Tesla blows away 99% of vehicles on the road today in 0-60 times, and in the real world that's much more useful than top speed.
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The numbers are nice, but when taken in context they don't make sense - for me. In the interest of proving the validity and potential of Ev's, for EV diehards, they are great milestones; bragging rights. For a person like me, looking to incorporate the technology into a project or two for marketing purposes the end doesn't justify the means. In other words, if I spent the same amount of money and time building an ICE-based vehicle I would get a LOT more bang for the buck; in performance numbers, in "wow factor", in longevity.
I'm not exactly sure what you are looking for, but does a high HP street rod really have more of a "wow factor" than a high performance EV, even if the EV doesn't perform as well as the street rod? Maybe for your target market it does, but you park a street rod next to a Tesla and which do you think will draw more attention? Is the street rod anything we haven't seen before? I do agree that there is a risk in going the EV route, no doubt, and in your situation, as in many, it might be better to play it safe since it sounds as if you have more riding on it. I've done a simple EV conversion and it worked out for me exactly as I had hoped. If it had failed it would not have been a disaster for me, just some cash out of pocket, but intensive research made me confident it should work. The basics of the Fiero conversion are about the same, it's been done many times before, and since my needs are limited there is no reason it can't work for me. The technology is available to do a high performance EV right now, and the technology is improving all the time. If I had more money I'd build one with this Fiero. Eventually I hope to be able to upgrade the controller and expand the battery pack. This motor should be capable of more power but is limited by the controller. If you build an EV with today's best batteries chances are very good there will be much better ones to replace them in 10 years. There will probably be better ones next year. Battery developments are exploding, pick an element on the periodic table and there is probably someone working on using it in a battery.
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11:06 AM
JRP3 Member
Posts: 318 From: Central NY State Registered: Jan 2009
I should probably point something out, I'm not actually a green nut job I have a 23 ft speed boat with a 454, I have a Jet Ski with a 2 stroke, I've built jacked up 4x4's and slammed them through the mud and bounced them off trees. But I can no longer ignore the realities of the consequences of those vehicles and I use them less and less. Cost, pollution, oil dependency, for me it's just not worth it any more and I need to do something different.
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11:17 AM
Marvin McInnis Member
Posts: 11599 From: ~ Kansas City, USA Registered: Apr 2002
I ... have a question for those of you who have firm grasp of physics. Is a lightweight, reasonably powerful EV actually possible, or will it always be one or the other?
I'll nominate myself as educated in physics and engineering, as well as knowledgeable with some real-world experience in the area of alternative energy and electric vehicles.
You left out two other important variables in the EV equation: range and cost. With the EV technologies commercially available today at reasonable cost, you can indeed build a "lighweight, reasonably powerful" EV (see below), but its range will probably be less than two or three miles. Control sophistication (i.e. smoothness and flexibility of control) is another important variable in a real-world EV, but it isn't directly relevant to your original "weight vs. power" question.
Assuming reasonable range, weight primarily depends upon the required battery capacity (in watt-hours) and the energy density (in both watt-hours per pound and watt-hours per cubic foot) of the battery technology chosen.
Ignoring battery internal impedance (i.e. resistance) for the moment, power is almost entirely a function of the motor and controller selected. This has relatively little effect on total vehicle weight, but it may significantly affect cost.
Cruising at constant speed on flat roads, range is almost entirely dependent upon vehicle aerodynamics, battery capacity, and motor/controller efficiency. In constant-speed driving in hilly terrain and/or in a stop-and-go urban driving environment, vehicle weight (and thus battery weight) tends to become the dominant factor; dynamic braking can help improve effiency somewhat in this operating regime.
Cost is the most complex variable to evaluate, since it's dependent upon almost every technical decision. It's most important here to clearly differentiate between one-time costs (e.g. chassis, essential systems, motor, controller, charger, wiring, etc.) and recurring costs (e.g. batteries, cost of electricity, maintenance, etc.) Battery cost will probably dominate the total cost of ownership of an EV for many years to come.
For a fun example of a lightweight, high performance EV, see this link.
[This message has been edited by Marvin McInnis (edited 01-18-2009).]
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11:28 AM
JRP3 Member
Posts: 318 From: Central NY State Registered: Jan 2009
Originally posted by Marvin McInnis: ...You left out two other important variables in the EV equation: range and cost. With the EV technologies commercially available today at reasonable cost, you can indeed build a "lighweight, reasonably powerful" EV (see below), but its range will probably be less than two or three miles...
Yes I did, but you answered my question perfectly The typical range of 40 miles per charge would work, less than two or three is what I expected to hear. Cost is negotiable depending on the end result. I am more concerned with the results as compared to the same investment in some other option - whatever the exact figure.
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Originally posted by Marvin McInnis: ...Control sophistication (i.e. smoothness and flexibility of control) is another important variable in a real-world EV, but it isn't directly relevant to your original "weight vs. power" question...
I have two different projects - that would be a concern with one and not with the other (street rod). I was thinking specifically about the street rod when asking, so I just addressed the two primary areas of concern.
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Originally posted by Marvin McInnis: ..For a fun example of a lightweight, high performance EV, see this link.
link no working?
Your post really helped, thanks
[This message has been edited by toddshotrods (edited 01-18-2009).]
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01:46 PM
fieroboom Member
Posts: 2132 From: Hayden, AL (BFE) Registered: Oct 2008
If it seems like I am trying to bash the whole EV "thing" I am not. I am picking it apart because it really has my interest
The advantages I see in developing a custom vehicle marketing tool with it:
* High-tech, futuristic, cutting-edge image * No radiator, water pump, cooling hoses etc. (clean) * No exhaust system (clean) * Compact motor (clean with interesting packaging options) * No traditional grille shell needed for cooling - opens serious doors for exterior styling opportunities - I have a land speed thing in mind for the street rod
My street rod has a nitrous bottle that is an integral design element of the car. I thought about what I would do with it if I went the EV route, and came up with the idea of using it to cool the controller and motor during serious acceleration events.
Just dreaming, I'm still not sold on it yet...
[This message has been edited by toddshotrods (edited 01-18-2009).]
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02:00 PM
fieroboom Member
Posts: 2132 From: Hayden, AL (BFE) Registered: Oct 2008
I think what you are missing is you are assuming DC motors will perform better and you are not taking into account the inefficiencies that are involved with brushed DC motors. What I'm saying is simple, even in a DC system there are losses in the controller itself, so the motor doesn't see the full 108 volts, and then there are further losses in the DC motor. AC systems may have more losses in the conversion to DC but have fewer losses within the motor itself. Coupled with a flatter torque curve this is why in the real world AC systems give an overall better performance than DC. Yes a DC motor will have better low end torque. You also keep ignoring the fact that AC systems allow energy to be returned to the pack while braking and series DC motors do not. All I know is that people have done 108 VDC conversions and been happy with them, and one person replaced his 8 inch DC motor with an 8 inch AC motor at the same voltage and got better performance. You obviously know a lot about electronics so how can you not be aware of the losses in a series, brushed, DC motor? If you are talking about a brushless DC motor that's another story but that is not an option as there are very few in EV sizes. Somehow you seem to be over estimating the conversion losses. Here is a chart at 48 volts for the smaller 6 inch version of the motor and controller I'm considering. They show about a 95% controller efficiency, much higher than what you claim, and an overall system efficiency, (motor plus controller), of about 83%. Either they are lying or you are wrong, I'd really like to know which before I buy it. Something isn't adding up. http://www.thunderstruck-ev...rive_performance.htm
Ok, I decided to do some research for you relating to my concerns. The only point I'm trying to make is that starting with 108 VDC isn't high enough for an AC system. I am not by any means disagreeing with you that AC is overall more efficient... in fact, I agree totally. However, one of the major points of an AC system is that it's high voltage/low amperage. That's a pro and a con within itself, because it means that you don't need as large of a gauge of wire, but you need a much larger battery pack, and since (as mentioned above) the pack will most likely be the highest cost item, I believe that once you get your system all set up with your 108 V, you'll discover that it's insufficient, but at that point, you can't just add more batteries, because your controller won't match up, which means more $$ you'll have to spend. http://www.cameronsoftware....ev/EV_DriveType.html
This guy has an absolute WEALTH of information, including manufacturers, batteries, and he actually uses ultracapacitors... http://www.metricmind.com/ac_honda/main2.htm Also note that his AC system is ~395 V
Every AC EV I have looked at is in the 300VDC range, which tells me that your 108VDC isn't going to cut it. Since I've never actually performed a conversion, it is absolutely possible that I'm wrong, and honestly, I hope I am... But I don't think I'm missing anything. I would just hate to see you get it all put together and find out that you need 3x the voltage, and a new controller, or else settle for swapping to DC and throwing away your regen braking abilities... Either way, you'd lose money, and that's all I'm trying help with.
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02:21 PM
Marvin McInnis Member
Posts: 11599 From: ~ Kansas City, USA Registered: Apr 2002
The Oregon Public Broadcasting web site seems to be the problem, but Google still has it cached as of today (1/18/2009). Google "Electric-Drag-Racing," find the "Oregon Field Guide" link, and click on "cached."
The Oregon Public Broadcasting web site seems to be the problem, but Google still has it cached as of today (1/18/2009). Google "Electric-Drag-Racing," find the "Oregon Field Guide" link, and click on "cached."
Okay, I have that one saved to favorites already. Actually, that car is one of the ones that kept my interest going when I was ready to write this off. Since he can acheive that with a steel bodied car, with small tires, I see the potential for lots more performance and some additional weight savings. My street rod body will be a carbon fiber/foam composite that will weight next to nothing, so I am essentially driving a powertrain and chassis. Also, I have a pretty substantial amount of rubber in back to start, and the option to put virtually any size I want for straight-line acceleration due to the fact that I have no body or fenders to tuck them under. With really light weight and huge tires my car would theoretically pull very impressive 60ft annd 0-60mph numbers. I also want to run slalom and skipad with it, which is one of the main reasons I am so determined to keep the weight as low as possible. I had planned on some road course work as well, but wonder if my ideal combination would have enough juice to make it around the track. I know heavy vehicles can handle reasonably well, but that's not for me.
i ran my 1976 dodge power wagon on hydrogen .as an experiment with it ,it blew up ,but it did run for several years.i dont know if i would run a fiero on hydrogen because of the likeliness to catch fire.
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04:55 PM
Jan 19th, 2009
JRP3 Member
Posts: 318 From: Central NY State Registered: Jan 2009
Every AC EV I have looked at is in the 300VDC range, which tells me that your 108VDC isn't going to cut it. Since I've never actually performed a conversion, it is absolutely possible that I'm wrong, and honestly, I hope I am... But I don't think I'm missing anything. I would just hate to see you get it all put together and find out that you need 3x the voltage, and a new controller, or else settle for swapping to DC and throwing away your regen braking abilities... Either way, you'd lose money, and that's all I'm trying help with.
I'm always happy when someone questions my knowledge and makes me dig deeper. I'm always willing to learn something new, that's how I improve. I totally agree that higher voltage is better, be it AC or DC, but it's just not in the budget right now. There is another relatively low voltage AC system, the Solectria/Azure AC 24, which runs at 156 volts I think, but it's a more expensive system than what I'm looking at but has similar output, and I'd need more batteries so that bumps up the cost even further. Victor at Metricmind has some great stuff, but way out of my budget. I'm still somewhat undecided as to which way I'm going. I'm trying to find some more people who have used the AC system I'm looking at. Worst case scenario if that motor and controller isn't up to the task in the Fiero, it would make a hell of a street bike setup
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12:25 AM
toddshotrods Member
Posts: 1177 From: Columbus, OH, USA Registered: Aug 2004
Originally posted by JRP3: ...it would make a hell of a street bike setup
I was impressed and tempted by the motorcycle stuff on the Thunderstruck site. Their "Hot" setup has a 50 mile range, 80mph top speed, and is around 338lbs. I like those numbers and wouldn't care about high performance. I have a metric-bike based chopper project that has been on hold for years that would work perfectly with that setup (another marketing tool). It would also fit my intended usage plans, which were to just putt around town (when not actually being used in an exhibition) because it's a hardtail design that wouldn't be practical for touring or high speeds.
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12:41 AM
Primaris Member
Posts: 550 From: Oak Grove, KY USA Registered: Aug 2001
I was impressed and tempted by the motorcycle stuff on the Thunderstruck site. Their "Hot" setup has a 50 mile range, 80mph top speed, and is around 338lbs. I like those numbers and wouldn't care about high performance. I have a metric-bike based chopper project that has been on hold for years that would work perfectly with that setup (another marketing tool). It would also fit my intended usage plans, which were to just putt around town (when not actually being used in an exhibition) because it's a hardtail design that wouldn't be practical for touring or high speeds.
Sorry I have to ask; What exactly is impressive about a 50 mile range and 80 mph top speed? Why bother? A scooter can get 100+mpg and 70mph top speed.
Well, For one thing the scooter doesn't have the cool factor of a hardtail.
Ding ding ding!!! With instant-on torque I'll bet the EV chopper would be a fun ride for those 50 miles too! Puttin around town on a chopper is all about image, and that's kind of hard to accomplish on a scooter. Two guys roll past a group of girls standing on the sidewalk. One is on a shiny new scooter, the other is on a raked-out, fat-tired, hardtail, chopper - which one do you think they're gonna flirt with
I have to get that out of my head before I talk myself into it
[This message has been edited by toddshotrods (edited 01-19-2009).]
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05:22 PM
PFF
System Bot
JRP3 Member
Posts: 318 From: Central NY State Registered: Jan 2009
Ding ding ding!!! With instant-on torque I'll bet the EV chopper would be a fun ride for those 50 miles too! Puttin around town on a chopper is all about image, and that's kind of hard to accomplish on a scooter. Two guys roll past a group of girls standing on the sidewalk. One is on a shiny new scooter, the other is on a raked-out, fat-tired, hardtail, chopper - which one do you think they're gonna flirt with
I have to get that out of my head before I talk myself into it
So then what do the girls think when you say, "oops babe we're at 49 miles. Do you have some spare batteries in your purse?" Or, are you trying to say being "Green" is cool? I'd bet money that a girl would rather ride a hard tail that vibrates than an EV one, lol.
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06:15 PM
dratts Member
Posts: 8373 From: Coeur d' alene Idaho USA Registered: Apr 2001
That's what the dancers said at a bar I used to work at. They said riding a Harley was like riding a big vibrater. Still, there is that cool green factor. I'm just not sure green is cool to girls. I never had any solar groupies when I was in the business.
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06:21 PM
JRP3 Member
Posts: 318 From: Central NY State Registered: Jan 2009
So then what do the girls think when you say, "oops babe we're at 49 miles. Do you have some spare batteries in your purse?" Or, are you trying to say being "Green" is cool? I'd bet money that a girl would rather ride a hard tail that vibrates than an EV one, lol.
Five miles to dinner, twenty miles to her place, and the chopper can charge while you "talk".
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06:29 PM
toddshotrods Member
Posts: 1177 From: Columbus, OH, USA Registered: Aug 2004
So, if I decide to go EV and want to get my feet wet with an around-town/fairgrounds speed setup, while I develop a real race system where's the best place to purchase a used 36-ish volt forklift motor/controller setup?
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06:38 PM
Primaris Member
Posts: 550 From: Oak Grove, KY USA Registered: Aug 2001
That's what the dancers said at a bar I used to work at. They said riding a Harley was like riding a big vibrater. Still, there is that cool green factor. I'm just not sure green is cool to girls. I never had any solar groupies when I was in the business.
"Green," isn't cool to anyone. Male or female...
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06:50 PM
toddshotrods Member
Posts: 1177 From: Columbus, OH, USA Registered: Aug 2004
Kermit is cool to everyone, though even he said, "it isn't easy..." So, you just stopped by this thread to let everyone know how lame you think this is?
[This message has been edited by toddshotrods (edited 01-19-2009).]
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07:18 PM
JRP3 Member
Posts: 318 From: Central NY State Registered: Jan 2009
So, if I decide to go EV and want to get my feet wet with an around-town/fairgrounds speed setup, while I develop a real race system where's the best place to purchase a used 36-ish volt forklift motor/controller setup?
Check the local salvage yards nearby if you want to go low dollar, you might be able to find a good 48 volt motor for real cheap. I wouldn't bother to use the forklift controller, I'd get an Alltrax 48 volt 400 amp, or you could get an Alltrax 72 volt which would allow you to up the voltage in the future without buying a new controller. Carl at www.EVDrives.com sometimes has good used Alltrax's as well as new ones. Also watch Ebay. You probably want at a 6-7 inch dia. motor between 40-60lbs. Read through as much as possible the thread on www.diyelectriccar.com titled "Using a forklift motor and choosing a good one". If you're really going to do this you should join the forum there.
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08:42 PM
toddshotrods Member
Posts: 1177 From: Columbus, OH, USA Registered: Aug 2004
Thanks for the links. Thay have 48-72V (brand new) kits for around $1500, deal or no deal? I still gotta pass on the DIY forums for now. I found the thread and skimmed over a couple posts then quickly clicked the little red "X" in the upper right hand corner of the tab! You can't send an addict into the bar to get a handful of peanuts man!
I haven't made a decision yet, but I am obviously giving this serious consideration. If I do it, I will hire people/companies to do the actual electric powertrains - the initial low power cruise system, and the desired race system. I am limiting my role to designing and developing the vehicle, and physically incorporating the system into the vehicle. If I do it, I will be pushing whoever does the actual system development to incorporate as much of what has been discussed in this thread (concerning EVs) as possible.
Some of the things discussed here that I am "chewing on":
Regenerative Braking Is there any way to have it with a DC system? I thought of having another (AC) motor that was set up as a generator during braking, and just freewheeling during acceleration and coasting, but that means adding a lot of weight - you probably know how I feel about weight. I want DC because I plan to do a lot of straight-line acceleration runs and want to be able to crank the juice up for more power.
Ultra Capacitors I'll be eyeballing developments with this because, if it really works, it would make my all-around performance goals more feasible.
Lithium Batteries I hope they continue to get smaller, deliver more, and cost less, like most tech stuff does. I can design the passenger area to have mounts for additional packs for performance runs, but ideally I hope they get small and light enough to allow me to run a pretty potent (but lightweight) setup everyday.
Another thought I had was about sound. I was remember reading or hearing (somewhere in all these links or in this thread?) that the controllers cycle the power "pulses" to cause the motor to resonate at frequencies beyond human hearing. Just like we go through the trouble of removing the nice quiet factory mufflers for Flowmasters, Dyno Maxes, and Borlas, could a controller be setup to purposely cause the motor to resonate at a "pleasing" frequency?
[This message has been edited by toddshotrods (edited 01-19-2009).]
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10:21 PM
JRP3 Member
Posts: 318 From: Central NY State Registered: Jan 2009
Thanks for the links. Thay have 48-72V (brand new) kits for around $1500, deal or no deal?
That doesn't sound bad but I haven't looked through their kits to see what's offered but I think you could do better, though it would take some shopping and finding deals. My 6x6 conversion cost me about $2100 for everything including batteries. You can check the details here if you haven't seen it yet: http://amp-phibian.blogspot...8_02_01_archive.html
quote
Some of the things discussed here that I am "chewing on":
*Regenerative Braking Is there any way to have it with a DC system? I thought of having another (AC) motor that was set up as a generator during braking, and just freewheeling during acceleration and coasting, but that means adding a lot of weight - you probably know how I feel about weight. I want DC because I plan to do a lot of straight-line acceleration runs and want to be able to crank the juice up for more power.
People have added alternators re-wound for higher voltage to recharge the pack on braking but I've never seen it done on a bike for obvious reasons. Not to say you cant but you'd probably be better off using the space and weight for more battery.
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Ultra Capacitors I'll be eyeballing developments with this because, if it really works, it would make my all-around performance goals more feasible.
Yeah, you and me both, but don't hold your breath waiting for these. We are all still waiting for proof. Lithium Batteries
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I hope they continue to get smaller, deliver more, and cost less, like most tech stuff does. I can design the passenger area to have mounts for additional packs for performance runs, but ideally I hope they get small and light enough to allow me to run a pretty potent (but lightweight) setup everyday.
Nice thing about bikes is the small pack can recharge fast, or even be made to swap out for a fresh one if it's not too large.
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Another thought I had was about sound. I was remember reading or hearing (somewhere in all these links or in this thread?) that the controllers cycle the power "pulses" to cause the motor to resonate at frequencies beyond human hearing. Just like we go through the trouble of removing the nice quiet factory mufflers for Flowmasters, Dyno Maxes, and Borlas, could a controller be setup to purposely cause the motor to resonate at a "pleasing" frequency?
Most controllers are such high frequency you can't hear anything, maybe a hiss, but the Curtis controllers have an odd squeal at slow speed because they drop the frequency way down at low speeds. Most people find it annoying, some more than others. The pulse width modulation frequency is built into the controllers and I don't think it's adjustable, but I could be wrong.
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10:41 PM
toddshotrods Member
Posts: 1177 From: Columbus, OH, USA Registered: Aug 2004
Originally posted by JRP3: ...but I've never seen it done on a bike for obvious reasons.. Nice thing about bikes...
This is for the street rod, not the chopper. The chopper sounds like fun but I started getting distracted from what I am supposed to be doing just thinking about it.
Thanks for the tip on the alternator, I'll check into that one.
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10:54 PM
JRP3 Member
Posts: 318 From: Central NY State Registered: Jan 2009
I forgot one thing. DC motors that are SHUNT wound (or SEPEX, separately excited), CAN do regen with the right controller. Shunt wound motors are harder to find, usually more expensive, and harder to get controllers for. EVdrives does have some shunt motors but they are open faced with no support bearing because I think they are meant to bolt directly to a golf cart axle. Some forklifts use shunt motors. If you go with shunt motors you'd want the Alltrax DCX controller, series motors use the Alltrax AXE. I just noticed my 6 wheeler is still a featured vehicle on evdrives For price comparison I got my 7.5 inch rebuilt Yale forklift motor from Jim Husted at HiTorqueelectric.com for $500, but he doesn't always have motors in stock. Compare that to the new 6.5 inch D&D motor at EVdrives for $750.
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10:56 PM
JRP3 Member
Posts: 318 From: Central NY State Registered: Jan 2009
So then what do the girls think when you say, "oops babe we're at 49 miles. Do you have some spare batteries in your purse?" Or, are you trying to say being "Green" is cool? I'd bet money that a girl would rather ride a hard tail that vibrates than an EV one, lol.
And I'm betting money that your girl would rather ride anything but you, especially if your 'other' skills are anywhere near your advice skills... I bet you just rock her world with that "I'm better than you" attitude... But anyway, thanks for stopping by and offering your pitiful useless advice.
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10:58 PM
Jan 20th, 2009
toddshotrods Member
Posts: 1177 From: Columbus, OH, USA Registered: Aug 2004
Sorry for the hijack guys, I got a little excited because I saw the potential... I'm ready to talk less, listen more, and learn a lot, so please continue the regularly-scheduled advanced propulsion discussion.
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01:05 AM
Primaris Member
Posts: 550 From: Oak Grove, KY USA Registered: Aug 2001
...So, you just stopped by this thread to let everyone know how lame you think this is?
er, no actually I've been in this thread long than you. Not that that matters.
quote
Originally posted by JRP3:
I guess some people think pollution is cool.
Where did I ever say that? Causing gross, unnecessary pollution, is anything but cool. Just because something runs on electricity does not mean it is better for the environment. All it does is use less gasoline and more coal, oil, or natural gas.
I have a 23 ft speed boat with a 454, I have a Jet Ski with a 2 stroke, I've built jacked up 4x4's and slammed them through the mud and bounced them off trees. But I can no longer ignore the realities of the consequences of those vehicles and I use them less and less. Cost, pollution, oil dependency, for me it's just not worth it any more and I need to do something different.
The typical range of 40 miles per charge would work, less than two or three is what I expected to hear. Cost is negotiable depending on the end result. I am more concerned with the results as compared to the same investment in some other option - whatever the exact figure.
