johnrobholmes
10 MW
If you want some 10C cells another great place is TrueRC. It is getting hard to find good 10C stuff anymore.
The E-cumbent - A project by Matt Shumaker
- Thread starter Storm
- Start date
recumpence
1 GW
Yup, True RC is just a stones throw from me. They are still a touch high in price compared to MaxAmps, though.
Matt
Matt
TPA
10 kW
I'm still in the learning phase, I am considering those batteries and nicad, both because of the discharge rates. I like compactness of the lipos but I'll probably end up choosing the nicads because of the price and because I don't want to make my mistakes on high price equipment. My entire project will be a very slow mover because I'm an old man in engineering school, while working a full time job.
I did purchase my bike, its on the way. I chose the Forge 19.5" sawback 5xx, it gets 5 stars by everyone who takes the time to rate it.
After I gather enough information to be able to know with some degree of certainty that I will not blow myself up, I will make a decision on batteries.
I have not even decided on which hub motor yet..
:lol:
I did purchase my bike, its on the way. I chose the Forge 19.5" sawback 5xx, it gets 5 stars by everyone who takes the time to rate it.
After I gather enough information to be able to know with some degree of certainty that I will not blow myself up, I will make a decision on batteries.
I have not even decided on which hub motor yet..
:lol:
TPA
10 kW
Well........semi old....I'm 41.
safe
1 GW
- Joined
- Dec 22, 2006
- Messages
- 5,681
41 is a good age. You are still young enough that if you do regular exercise you can be near your younger age peak in performance. But it's just the point where you start to feel tired more often and you need longer to recover from everything.TPA said:
I'm 47... nearly 48 and in about as good a shape as can be expected. Sometimes after a few "hard days" of doing stuff I just need to take a day to rest... or two.
When I used to work in the corporate world I kind of liked being able to sit in a chair all day because then I was recovering all that time. Go to the gym in the morning, then sit all day... oh yeah and work too. :lol:
I look on the bright side... my dad died of cancer when he was only 46 years old... so I've outlived my dad already. :| (in a sense it feels like "borrowed time")
recumpence
1 GW
This is an update for my web page I sent to the host today..................................
I have put alot of miles on the bike this summer and have learned a great deal. One weak link on my bike became apparent when I installed the Plettenberg motor. That new motor draws alot more current (and pushes the bike alot harder). However, with that extra power, I have found the controller cannot deal with it for long. After 100 miles of hard riding I blew the HV110 controller. I installed a new controller and that one lasted 100 miles as well. Hmm, frustrating. I spoke with Castle Creations about this, at length a number of times and I decided to go with another of their controllers designed for RC boat use. It is the Hydr HV240. That ESC is designed for 240 amps if liquid cooled or (according to Castle Creations) 160 amps without liquid cooling. Perfect! So, I ordered one. Once the new controller arrived I read the instructions. This new controller uses different programming than the HV110 airplane controller. There are too many differences to discuss here. But, suffice it to say, this new Hydra ESC is not going to be ideal for this application. Hmm, what to do? After staring at the Hydra for a while, I came up with an idea......... I noticed the Hydra has the same Logic board as the HV110 and uses teh same FET boards. However, the HV110 uses only 3 FET boards, while the Hydra uses 4 FET boards. I called Castle Creations and asked them if the HV110 logic board would snap onto the Hydra FET bank. They said absolutely! So, I merely unplugged the FET board from one of my blown HV110s and plugged it onto the Hydra. Perfect! Next I removed the liquid cooling tubes leaving the bare heat sinks. Lastly I removed two of the eight 180mf caps and added two 1,000mf caps in there place effectively increasing the capacitance from roughly 1,000mf to 3,000mf. You can see the two controllers and the differences between the two. I effectively built an HV160 controller.
I haven't run it yet. So, I will have to get back to you with the details on its performance. I will let you know how it runs when I get it back together!
I need to make it abundantly clear that this ESC issue is related to my use of the huge Plettenberg motor under hard accelleration. I have never run into anyone else blowing HV110s in bike use. So, please do not assume the HV110 is inadequate! I have merely been pulling 7,500 watts through a 5,500 watt controller. So, this is my solution. Also, Castle Creations is willing to custom make controllers with more FET boards for custom applications. They are costly and take 8 weeks to get, though. So, I went this route. We shall see how it performs!
More to come!
Matt
I have put alot of miles on the bike this summer and have learned a great deal. One weak link on my bike became apparent when I installed the Plettenberg motor. That new motor draws alot more current (and pushes the bike alot harder). However, with that extra power, I have found the controller cannot deal with it for long. After 100 miles of hard riding I blew the HV110 controller. I installed a new controller and that one lasted 100 miles as well. Hmm, frustrating. I spoke with Castle Creations about this, at length a number of times and I decided to go with another of their controllers designed for RC boat use. It is the Hydr HV240. That ESC is designed for 240 amps if liquid cooled or (according to Castle Creations) 160 amps without liquid cooling. Perfect! So, I ordered one. Once the new controller arrived I read the instructions. This new controller uses different programming than the HV110 airplane controller. There are too many differences to discuss here. But, suffice it to say, this new Hydra ESC is not going to be ideal for this application. Hmm, what to do? After staring at the Hydra for a while, I came up with an idea......... I noticed the Hydra has the same Logic board as the HV110 and uses teh same FET boards. However, the HV110 uses only 3 FET boards, while the Hydra uses 4 FET boards. I called Castle Creations and asked them if the HV110 logic board would snap onto the Hydra FET bank. They said absolutely! So, I merely unplugged the FET board from one of my blown HV110s and plugged it onto the Hydra. Perfect! Next I removed the liquid cooling tubes leaving the bare heat sinks. Lastly I removed two of the eight 180mf caps and added two 1,000mf caps in there place effectively increasing the capacitance from roughly 1,000mf to 3,000mf. You can see the two controllers and the differences between the two. I effectively built an HV160 controller.
I haven't run it yet. So, I will have to get back to you with the details on its performance. I will let you know how it runs when I get it back together!
I need to make it abundantly clear that this ESC issue is related to my use of the huge Plettenberg motor under hard accelleration. I have never run into anyone else blowing HV110s in bike use. So, please do not assume the HV110 is inadequate! I have merely been pulling 7,500 watts through a 5,500 watt controller. So, this is my solution. Also, Castle Creations is willing to custom make controllers with more FET boards for custom applications. They are costly and take 8 weeks to get, though. So, I went this route. We shall see how it performs!
More to come!
Matt
johnrobholmes
10 MW
Hosss!!! Hossss!!!!!
Hope it does well for you!
Hope it does well for you!
recumpence
1 GW
You and me both.
Matt
Matt
dirty_d
10 kW
isnt your pack over 50V when its fully charged? if those capacitors fail then the fets probably will too. how is that current limited throttle coming? im not sure if you even started yet or not but it should be fairly simple. you could have a regular ebike throttle go to a microcontroller where it converts the throttle voltage to a desired current say like 0-100A so you dont fry the controller anymore. it could watch the voltage across the shunt on your controller and increase the throttle signal sent to your controller until the current through your controller equals the current desired by the regular throttle, if the current goes over the desired current it just reduces the throttle signal sent to the controller. it wont have a super fast response since the controller uses a pulse every 20ms or so but it should still be faster than you will be able to physically move the throttle and faster than the grade of the road will change. if you have any questions just ask. i just blew my brushed motor so i finally have an excuse to get a big powerfull brushless one and make a controller for it, one of my main goals will be making it as cheap as possible, ill make everything open-source so other people can build it.
recumpence
1 GW
My pack is 48 volts fully charged.
Nope, no current limiter yet. The engineer I know started his own business this summer and my project is on the back burner (read NEVER going ot happen).
So, if anything happens, it will have to be done by me. Hmm, my electronic skill is NOT far enough for that. I understand the limiter, in theory. But, in practice, I have other more pressing things I could devote my time to. Besides, I like lots of power! 
Matt
Nope, no current limiter yet. The engineer I know started his own business this summer and my project is on the back burner (read NEVER going ot happen).
So, if anything happens, it will have to be done by me. Hmm, my electronic skill is NOT far enough for that. I understand the limiter, in theory. But, in practice, I have other more pressing things I could devote my time to. Besides, I like lots of power! Matt
Jeremy Harris
100 MW
Matt,
Thanks for posting that snippet about the separate control and power boards, it's given me an idea.
The main limitations with using RC controllers seems to be the need to run at low voltages and operate the controllers in an area they may not have been designed for. On a model aircraft (or helo) prop power absorption is proportional to the cube of speed, so aircraft controllers rarely see high power demand at low rpm for more than just motor start and acceleration. For an ebike, the power demand for acceleration at low speed and to overcome rolling resistance is greater, so presumably the controller will be handling much high current at low speeds then it may have been designed for.
If the control board can be fed with a regulated supply that's less than the main battery pack voltage, and if a new power board, designed for ebike use, with big fets and a decent heatsink, was added, this might add some robustness and allow the use of higher supply voltages, so reducing the current needed for any given power.
Making a new power board would be pretty straightforward, I think. All it would seem to need would be some big FETs, some FET drivers, the power caps plus a voltage regulator to feed the control board with a lower voltage. All the clever stuff remains in the original RC controller control board. It might be necessary to add some potential dividers to reduce the back EMF feedback voltage to the control board, depending on how sensitive it is to having a few more volts fed back to it.
All round, this might make an economic solution to a high power, high voltage, controller for these big motors.
BTW, what's the start up like on your recumbent, Matt? Does that big motor start well from zero rpm?
Thanks for keeping us posted with developments.
Jeremy
Thanks for posting that snippet about the separate control and power boards, it's given me an idea.
The main limitations with using RC controllers seems to be the need to run at low voltages and operate the controllers in an area they may not have been designed for. On a model aircraft (or helo) prop power absorption is proportional to the cube of speed, so aircraft controllers rarely see high power demand at low rpm for more than just motor start and acceleration. For an ebike, the power demand for acceleration at low speed and to overcome rolling resistance is greater, so presumably the controller will be handling much high current at low speeds then it may have been designed for.
If the control board can be fed with a regulated supply that's less than the main battery pack voltage, and if a new power board, designed for ebike use, with big fets and a decent heatsink, was added, this might add some robustness and allow the use of higher supply voltages, so reducing the current needed for any given power.
Making a new power board would be pretty straightforward, I think. All it would seem to need would be some big FETs, some FET drivers, the power caps plus a voltage regulator to feed the control board with a lower voltage. All the clever stuff remains in the original RC controller control board. It might be necessary to add some potential dividers to reduce the back EMF feedback voltage to the control board, depending on how sensitive it is to having a few more volts fed back to it.
All round, this might make an economic solution to a high power, high voltage, controller for these big motors.
BTW, what's the start up like on your recumbent, Matt? Does that big motor start well from zero rpm?
Thanks for keeping us posted with developments.
Jeremy
johnrobholmes
10 MW
Jeremy,
There isn't actually an issue with the currents at low RPM, there is more issue with the huge motor Matt is using. While the plane controllers aren't built to take huge bursts over the rated continuous current (thinner copper traces mostly), the ground controllers are indeed built to handle huge startup surges with the same basic hardware. For example, the HV110 will handle 150 amp surges pretty well. The Monster Max from Castle is rated 200a continuous but till take over 800 surge because of the massive copper traces. Since the plane controllers are readily available in high voltage we are stuck using motors and gearing that will peak closer to the continuous rating of the controller. Boo hoo, only 5,000w on an HV110 right ? :lol:
There isn't actually an issue with the currents at low RPM, there is more issue with the huge motor Matt is using. While the plane controllers aren't built to take huge bursts over the rated continuous current (thinner copper traces mostly), the ground controllers are indeed built to handle huge startup surges with the same basic hardware. For example, the HV110 will handle 150 amp surges pretty well. The Monster Max from Castle is rated 200a continuous but till take over 800 surge because of the massive copper traces. Since the plane controllers are readily available in high voltage we are stuck using motors and gearing that will peak closer to the continuous rating of the controller. Boo hoo, only 5,000w on an HV110 right ? :lol:
recumpence
1 GW
Jeremy,
My startup is very smooth. I do get the occasional very slight stutter for 1/4 second at innitial startup. But, that is not the motor jearking back and forth. It will once in a while run (in the correct direction) with a very tiny stutter as it operates open loop untill it establishes back EMF sync. Again, it is only occasional, very slight, and very short (1/4 second or less).
John is correct. The issues I have had with controllers is my huge motor. I never had any problems with controllers when I was running my AXI. But, the AXI had sync issues that this motor does not have. Plus this motor is alot more powerful. If this ESC blows, I will assume there is a problem with my motor. I do not see how that is possible, though. Because I get 100 miles out of one HV110, then it blows (two controllers, same thing).
My bike is far beyond what nearly anyone else would run. So my experience with blown controllers is not typical. I almost feel bad that there is an assumption the VH110 has issues due to my experience. One cannot expect a 5,000 watt controller to tolerate 7,500 watts more than a couple times before blowing.
Matt
My startup is very smooth. I do get the occasional very slight stutter for 1/4 second at innitial startup. But, that is not the motor jearking back and forth. It will once in a while run (in the correct direction) with a very tiny stutter as it operates open loop untill it establishes back EMF sync. Again, it is only occasional, very slight, and very short (1/4 second or less).
John is correct. The issues I have had with controllers is my huge motor. I never had any problems with controllers when I was running my AXI. But, the AXI had sync issues that this motor does not have. Plus this motor is alot more powerful. If this ESC blows, I will assume there is a problem with my motor. I do not see how that is possible, though. Because I get 100 miles out of one HV110, then it blows (two controllers, same thing).
My bike is far beyond what nearly anyone else would run. So my experience with blown controllers is not typical. I almost feel bad that there is an assumption the VH110 has issues due to my experience. One cannot expect a 5,000 watt controller to tolerate 7,500 watts more than a couple times before blowing.
Matt
Jeremy Harris
100 MW
Thanks for the reassurance about start up, Matt.
I understand the rather unusual stresses you're putting on the controller, from all I've read those CC controllers are usually bullet proof.
The application I have in mind is a little different to yours and has been outlined on the RC motors thread. In essence, I want to use several, slightly smaller motors (they arrived in the post today, Tower Pro 5330's) connected together to form a cost-effective compound motor for a bigger vehicle. The sticking point for a budget system seems to be the cost of HV controllers. LV controllers are dirt cheap by comparison. Building a simple HV power board would also be relatively cheap, so there is a certain attractiveness to the idea. Looking at the component cost I think I could build a 24 FET power board, with drivers etc, for around £45 (about $90). A cheap (but good) LV controller would cost maybe another £15 (about $30) or so. This means I could perhaps have a controller that would handle around 100A at about 60V for less than £70 ($140), which looks attractive as I'm looking to run half a dozen controllers at a time.
If just looking to use one RC motor then I think I'd just bite the bullet and buy a big CC controller, rather than mess about with a home-built power stage.
Jeremy
PS: Great service from Hobby City in Hong Kong. Ordered motors at the weekend, arrived this morning, so less than three working days from China to the UK.
I understand the rather unusual stresses you're putting on the controller, from all I've read those CC controllers are usually bullet proof.
The application I have in mind is a little different to yours and has been outlined on the RC motors thread. In essence, I want to use several, slightly smaller motors (they arrived in the post today, Tower Pro 5330's) connected together to form a cost-effective compound motor for a bigger vehicle. The sticking point for a budget system seems to be the cost of HV controllers. LV controllers are dirt cheap by comparison. Building a simple HV power board would also be relatively cheap, so there is a certain attractiveness to the idea. Looking at the component cost I think I could build a 24 FET power board, with drivers etc, for around £45 (about $90). A cheap (but good) LV controller would cost maybe another £15 (about $30) or so. This means I could perhaps have a controller that would handle around 100A at about 60V for less than £70 ($140), which looks attractive as I'm looking to run half a dozen controllers at a time.
If just looking to use one RC motor then I think I'd just bite the bullet and buy a big CC controller, rather than mess about with a home-built power stage.
Jeremy
PS: Great service from Hobby City in Hong Kong. Ordered motors at the weekend, arrived this morning, so less than three working days from China to the UK.
recumpence
1 GW
I have my Hydra 240 hooked up and running. It turns out the logic board from the HV110 does not work with the Hydra. So, I put the Hydra logic board back in. I got it all setup and running.
Here is the good and the bad............
The good news is, the software is awesome on this controller (startup software). However, being designed for racing, the timing is too far advanced even at the lowest setting for my motor. So, it runs well, but loses sync occasionally if I throttle it too hard. The HV110 never did that.
So, I am back to the HV110. What I am doing is setting the slipper clutch to slip at 90 amps. That should keep me well away from the danger zone for that controller. That is still 4,000 watts. That is plenty for anyone. But, admittedly, I am used to pulling 6,000+ watts. I like the accelleration! But, I need to be easy on this controller untill Castle releases the SHV200 late this year.
Matt
Here is the good and the bad............
The good news is, the software is awesome on this controller (startup software). However, being designed for racing, the timing is too far advanced even at the lowest setting for my motor. So, it runs well, but loses sync occasionally if I throttle it too hard. The HV110 never did that.
So, I am back to the HV110. What I am doing is setting the slipper clutch to slip at 90 amps. That should keep me well away from the danger zone for that controller. That is still 4,000 watts. That is plenty for anyone. But, admittedly, I am used to pulling 6,000+ watts. I like the accelleration! But, I need to be easy on this controller untill Castle releases the SHV200 late this year.
Matt
recumpence
1 GW
I wanted to check back with you guys and let you know where I am at with my bike......
Basically, I have the slipper clutch set to slip at 80 amps. That seems to be plenty of power. I also added two 1,000mf caps to the input of my HV110. The bike runs well this way.
I have also begun doing some serious testing with my data logger. The bike pulls 1,300 watts to sustain 39 to 40mph. I have seen under 1,000 watts at that speed, but, admittedly, that was with a tail wind. :wink:
Anyway, the bike draws 400 watts with the rear wheel off the ground, freewheeling at 44mph (full throttle). Also, it is pretty consistant that the bike draws 4 times as much power to double speed. So, 20mph requires well under 300 watts.
I will post a picture of the console with the display lit up so you can see what data I have while riding.
Matt
Basically, I have the slipper clutch set to slip at 80 amps. That seems to be plenty of power. I also added two 1,000mf caps to the input of my HV110. The bike runs well this way.
I have also begun doing some serious testing with my data logger. The bike pulls 1,300 watts to sustain 39 to 40mph. I have seen under 1,000 watts at that speed, but, admittedly, that was with a tail wind. :wink:
Anyway, the bike draws 400 watts with the rear wheel off the ground, freewheeling at 44mph (full throttle). Also, it is pretty consistant that the bike draws 4 times as much power to double speed. So, 20mph requires well under 300 watts.
I will post a picture of the console with the display lit up so you can see what data I have while riding.
Matt
GGoodrum
1 MW
That sounds great, Matt. If you have time, it would be great to see some pics of your setup with the HV110, and the caps. I'm still hoping to get time soon to start work on my Dahon 16"folding bike, using the Neumotor 2215 with the P62 6.75:1 gearbox. I have a PowerJazz I was going to use with it, but based on your experience, I'll probably end up with an HV110 as well. I won't be pulling anywhere near 90A, though. Probably on the order of 60-70A, tops.
Although I'm very happy with the performance of the Cyclone 1000W setup on my 20" Mariner, it sure does make a lot of racket. Eventually, I think I will replace the existing motor chain with either a smaller pitch chain, or a belt drive. For the Neumotor setup on the 16" Dahon, I think I'll start with a belt drive.
--Gary
Although I'm very happy with the performance of the Cyclone 1000W setup on my 20" Mariner, it sure does make a lot of racket. Eventually, I think I will replace the existing motor chain with either a smaller pitch chain, or a belt drive. For the Neumotor setup on the 16" Dahon, I think I'll start with a belt drive.
--Gary
recumpence
1 GW
Hey Gary,
Always good to hear from you!
I like your drive system idea. That motor will be (like my Pletty) way overkill. Is there any other way? :wink:
I think you will find 3,000 watts is the minimum you will want to hold your interest. My bike pulls 4,000 watts before my clutch slips. That seems fine, but (as you know with helis) more is always welcome!
Basically, I soldered my Eagle Tree 3 inches of wire from the board on my HV110. At that solder joint, I added the two 1,000mf caps. Pretty simple.
I have found when I run my Eagle Tree with display, I have alot more fun riding. It is cool watching my wattage. I can do my best to keep current consumption down when I can actually see what is going on. It is also good to see the display showing for instance) 560 watts to sustain "X" speed. Then I can start pedalling and watch my wattage drop to maybe 425 watts at the same speed. Very interesting indeed!
Matt
Always good to hear from you!
I like your drive system idea. That motor will be (like my Pletty) way overkill. Is there any other way? :wink:
I think you will find 3,000 watts is the minimum you will want to hold your interest. My bike pulls 4,000 watts before my clutch slips. That seems fine, but (as you know with helis) more is always welcome!
Basically, I soldered my Eagle Tree 3 inches of wire from the board on my HV110. At that solder joint, I added the two 1,000mf caps. Pretty simple.
I have found when I run my Eagle Tree with display, I have alot more fun riding. It is cool watching my wattage. I can do my best to keep current consumption down when I can actually see what is going on. It is also good to see the display showing for instance) 560 watts to sustain "X" speed. Then I can start pedalling and watch my wattage drop to maybe 425 watts at the same speed. Very interesting indeed!
Matt
GGoodrum
1 MW
One thing I learned with the Mariner is that even though it tops out at about 2700W, with the extra torque benefit that the gearing provides, it actually has better performance than the 5303/72V setup it replaced, and that one hit 5000W peaks. What I really like is being able to use a 16s/48V setup, instead of 24s/72V. With the latter, I can't use an Eagletree eLogger, and I have to use two WattsUp units.
For the 16" Dahon, I'm going for lightweight and simple, but I still want it to have decent performance.
For the 16" Dahon, I'm going for lightweight and simple, but I still want it to have decent performance.
recumpence
1 GW
I know what you mean.
Even though I have my bike setup for 4,000 watts, it is geared for 40mph. So, the accelleration (though powerful) is not nearly as powerful as it could be. If I geared this thing for 30mph, it would probably wheelie. :wink: Actually, when I tighten the clutch to pull 7,000 watts, the bike just starts to feel truely quick. Tall gearing really hampers accelleration.
My next build will be a mountain bike geared for about 22mph running roughly 2500 watts. That bike (with low gearing and a higher CG) should be a crazy wheelie machine even with far less power than my recumbent.
Matt
Even though I have my bike setup for 4,000 watts, it is geared for 40mph. So, the accelleration (though powerful) is not nearly as powerful as it could be. If I geared this thing for 30mph, it would probably wheelie. :wink: Actually, when I tighten the clutch to pull 7,000 watts, the bike just starts to feel truely quick. Tall gearing really hampers accelleration.
My next build will be a mountain bike geared for about 22mph running roughly 2500 watts. That bike (with low gearing and a higher CG) should be a crazy wheelie machine even with far less power than my recumbent.
Matt
MitchJi
10 MW
GGoodrum said:
Hi Gary,
I think a belt drive would be neat but might not be required to get a quieter system. If you used something similar to the low cost drive unit (supposed to be about $150) Matt is developing which is designed to have a 4:1 to 6:1 belt reduction from a motor shaft but used the output of the P62 to feed the belt your chain speed would be much lower, so I think that might resolve your chain noise issue. See here for more info on Matt's drive:
http://www.endless-sphere.com/forums/viewtopic.php?f=1&t=6163
Something else you might want to consider is putting a second sprocket (freewheeling) on the output of the motor or gear reduction. Then run one chain from the motor to the rear sprockets instead of running it to the front crank. Then run a second chain from your front crank to the freewheeling sprocket on the motor instead of to the rear sprockets. This would eliminate the motor from turning the crank. This would require a slightly more complex drive unit but would require no changes to the bike gearing (except changing sprocket sizes).
If you do this correctly (mostly gear ratios) this can be a very elegant solution. I test rode an ebike set up this way and it was almost silent and even though it only has a 500w motor performance was pretty good (climbs a 25% grade) as long as I was in the correct gear for a good cadence. This is the bike I am referring to:
http://pimobility.com/index.html
Matt:
If its not to long to fit between the pedals a Nue 2200 Series with the gearbox might be a good solution for your drive unit. The back of the motor would protrude from the tube but if it fits between the pedals that would be OK. The kv of Gary's motor is 480 but with the 6.7:1 gearbox its the equivalent to a kv of about 70. If the Nue 2200 Series is too long a 1900 Series with a 6.7:1 gearbox might work well if the gearboxes (P32) sold for that motor are strong enough.
recumpence
1 GW
Yup, the Neu with gearbox would probably work fine. The big push on my drive unit is low cost, however. I have Neu motors in RC cars and LOVE them. But, cost, and gearbox noise are my only issues.
I am finally beginning machining the box this week.
I will be posting on the gearbox thread when I start.
Matt
I am finally beginning machining the box this week.
I will be posting on the gearbox thread when I start.
Matt
GGoodrum
1 MW
I just read through the gearbox thread, and I think this is a great idea. I'm having a bit of trouble visualizing just exactly what this looks like, but the idea sounds great. I will go post some questions in that thread. I'm not sure how I missed that thread, but a just a suggestion for the future, you should post those types of topics in the Technical section. Nonetheless, a great topic.
Mitch, it never occured to me to basically put the motor drive essentially in series with the crankset, but this wold actually solve another problem, besides the noise issue, and that is having to have a freewheel in the crankset. These are hard-to-find items, and the one that comes with the Cyclone kit is of questionable quality.
The 1900 series motors are very popular with the electric RC helicoptor crowd. They were called ORKs, for OutRunner Killers, in that they have very large diameter stators, so they put out lots of torque at lower rpm, like an outrunner, but are gobs more efficient, a hallmark of all of Steve's motors. Anyway, the largest of these, the 1915, might be suitable, if you get the gearing right. You need to let these run up at around 20,000 rpm (they are good to easily about 60,000+...), to get the best torque/efficiency numbers. The 2200 series (with 2.2" stators, vs 1.9" on the 1900s...) have more torque at lower speeds, but even still, my plan is to run my 2215 off a 16s a123 setup, which will put the motor rpm at just over 20k, which is right at its "sweet spot". You can get lower kV versions, but I really like the idea of runnign the motor at 20k and using the extremely efficient 6.76:1 gearbox on the front end. This give it the same relative kV of my Cyclone 1000-1500W motor, but with 3 times the power/torque and in a much smaller, lighter, form factor.
For gearing, I'd like to get it close to what I did on my 20" Mariner, but maybe a bit taller, as it has almost too much torque in 1st gear of the Nexus 3-speed hub. It will just about pull an "uncommanded" wheelie, even with my 250 lb butt on it. Top spped, in 3rd, is about 30, which is plenty for a folder. Anyway, what I have on this setup is the stock 44T/6T motor-to-crank 1st stage, and thend from the pedals to the Nexus hub, a 24T sprocket up front and a 23T sprocket on the hub. I had worried that this setup wouldn't have enough low-end torque, so I replaced the 36T sprocket that came on the Cyclone crankset, with a 24T MTB "granny gear", which got the front-to-back ratio close to 1:1. With the Cyclone controller allowing 55A through the motor, which tops out at about 2700W on the WattsUp, there is more than enough torque available, so if I was to do it again, I'd probably leave the 36T front sprocket alone. That would also make the pedals a little more useful. With this setup, even pedaling in 3rd is pretty useless.
For my 16" Dahon Curve, which has a S-A 3-speed hub, I'd like to leave the existing "pedal" ratios alone, and have the motor drive/gearbox handle whatever is need to get the right end end ratios for the motor. With my planned setup, this would mean the optimum gearbox ratio I need is going to be somewhere around 8:1, I think.
-- Gary
Mitch, it never occured to me to basically put the motor drive essentially in series with the crankset, but this wold actually solve another problem, besides the noise issue, and that is having to have a freewheel in the crankset. These are hard-to-find items, and the one that comes with the Cyclone kit is of questionable quality.
The 1900 series motors are very popular with the electric RC helicoptor crowd. They were called ORKs, for OutRunner Killers, in that they have very large diameter stators, so they put out lots of torque at lower rpm, like an outrunner, but are gobs more efficient, a hallmark of all of Steve's motors. Anyway, the largest of these, the 1915, might be suitable, if you get the gearing right. You need to let these run up at around 20,000 rpm (they are good to easily about 60,000+...), to get the best torque/efficiency numbers. The 2200 series (with 2.2" stators, vs 1.9" on the 1900s...) have more torque at lower speeds, but even still, my plan is to run my 2215 off a 16s a123 setup, which will put the motor rpm at just over 20k, which is right at its "sweet spot". You can get lower kV versions, but I really like the idea of runnign the motor at 20k and using the extremely efficient 6.76:1 gearbox on the front end. This give it the same relative kV of my Cyclone 1000-1500W motor, but with 3 times the power/torque and in a much smaller, lighter, form factor.
For gearing, I'd like to get it close to what I did on my 20" Mariner, but maybe a bit taller, as it has almost too much torque in 1st gear of the Nexus 3-speed hub. It will just about pull an "uncommanded" wheelie, even with my 250 lb butt on it.
Top spped, in 3rd, is about 30, which is plenty for a folder. Anyway, what I have on this setup is the stock 44T/6T motor-to-crank 1st stage, and thend from the pedals to the Nexus hub, a 24T sprocket up front and a 23T sprocket on the hub. I had worried that this setup wouldn't have enough low-end torque, so I replaced the 36T sprocket that came on the Cyclone crankset, with a 24T MTB "granny gear", which got the front-to-back ratio close to 1:1. With the Cyclone controller allowing 55A through the motor, which tops out at about 2700W on the WattsUp, there is more than enough torque available, so if I was to do it again, I'd probably leave the 36T front sprocket alone. That would also make the pedals a little more useful. With this setup, even pedaling in 3rd is pretty useless.For my 16" Dahon Curve, which has a S-A 3-speed hub, I'd like to leave the existing "pedal" ratios alone, and have the motor drive/gearbox handle whatever is need to get the right end end ratios for the motor. With my planned setup, this would mean the optimum gearbox ratio I need is going to be somewhere around 8:1, I think.
-- Gary
Similar threads
