 |
They thought they had to use hub motorson this cycletruck but to haul about640lbs / 290kg (total combined weight) withhub motors is an extreme waste of energy;even if you have 4 hub motors, they willbe in the wrong gear for hill climbing!2 or more '5:1 geared' hub motors could do it, but it would be much cheaper using onemotor with a proper gear reduction, like13:1 (or more) depending on your worst hill,the motor's operational speed andwattage you are limited to. |
 |
http://www.work-bikes.de/avd/van.htm |
 |
| http://www.work-bikes.de/avd/casestudies.htm |
 |
| Looks like a big motor with electronics to try to replace gears http://commutercycling.blogspot. com/2016/05/vector-control.html |
More about the laws http://commutercycling.blogspot.com/2011/01/blog-post_2907.html
 |
| http://ledreview.info/2013/printers-terratrike-velomobile-skinning-is-completed/ |
 |
| http://bicycledesign.net/2015/02/a-collection-of-velomobile-links-part-1/ |
 |
| velomobile cgi |
Mid-drives / Zero Trail Steering / Variable Speed Crank / Tilting trike technology
 |
| http://www.kreuzotter.de/english/espeed.htm |
The
most important parts
Hubs
with cartridge bearings, the idiot bicycle industry has virtually
stopped making bearings with loose balls. And the last one I bought
no longer has parts available; like the cones! (never buy Shimano
hubs)
Wheels
built with rigid spoke configuration, when spokes move due to
looseness they are guaranteed to break. Heavy duty wheels
Hydraulic
disc brakes, it will take you much longer to stop in the rain
with so much weight that you need a motor. A double hydraulic
disc brake is the only way to go for 600 to 800lbs.
Proper
gear reduction for enough torque thrust to keep the motor form
over heating. Using a 20 inch drive tire will make this much easier
to achieve. And cheaper to find a heavy duty tire (16” moped is
20”O.D.)
How
to power a heavy Velomobile or Cycle-truck.
Velomobiles
can get a get an efficiency of 40 miles to 85 miles per kilo watt hour of
electricity. While it is easy to build a Vehicle light enough to get the really
high mileage number at a slow speed on flat land, try thinking about how to
power one that will hold two adults and 80lbs of cargo. Or a cycle-truck that
will not be heavier than 600lbs (total combined weight) that will be driven up
a 9% grade. We have worse hills but they are avoidable. If you think that is
bad do the numbers on the new electric cars! 3.7 per kWh is high mileage.
I think the main reason that there is not much knowledge about this kind of
vehicle is no one knows how to build one.
Most people build only for speed, unfortunately if you’re in a wreck and you get
blamed for it the cops have to send your vehicle to be checked out by a
technician, to make sure it cannot be driven faster than the speed limit for
this kind of vehicle. So your best bet is to have it registered as a moped, or
a motor-cycle. Using only one motor you could gear the motor down to the 30 mph
limit, if it is still powerful enough to climb your steepest hills.
An
option you might consider is using a multiple Kw capable motor and using a
programmable controller to keep the total power running through the motor
within legal limits but still allow multiplying up the phase amps for torque
when hill climbing in the motors lower end.
For example let’s say you used a 4.5-Kw rated 72V high power scooter motor.
Normally you would use a controller with such a motor that would allow for
motor phase amps to reach nearly 200-Amps with a battery side Amp limit of
65-Amps or so. You would end up with an electric motorcycle that could really
move.
For
a lower total power build, within e-bike legal limits, you still use the same
motor and still use a large powerful controller that can handle phase amp
multiplication. One that goes all the way up to the that 200-Amp level when the
motor gets bogged down when climbing a hill, to get the full torque. But if you
program in a much lower Amp limit on the battery side, thus ensuring you stay
within legal total power limits, you still get the bottom end torque. Also you
don't need a great big battery that can handle sustained 65-Amps pull on the
battery end.
My state the legal power limit, for it to still be a Moped bicycle by the
letter of the law is "2-brake-horsepower maximum" which is equivalent
to 1.49-Kw physical output power. "Brake-horsepower" defines a motors
physical output power not the electric power input. Thus in my situation I
would examine the motors performance graphs and figure out what battery-side
amp limit I should program in, to ensure that I stayed within that limit
(knowing the general performance curves of such motors on a 72V system that would
probably end up being about a 25-to-30 Amp limit on the battery side).
Basically use a much bigger motor and controller and just dial down the Amp
limit on the battery side and thus tapper off the middle to the top band of the
motors performance but still keep all, or nearly all, of the high torque
capability of the bigger motor on its bottom end.
You do not want not to add speed to a 600lb vehicle. One of these motors can
pop a bicycle drive chain easily. You will need a “Cycle Annalist” to help control
the vehicle. And a controller that will read the Cycle Annalist. And at 600lbs
with a speed of 30 mph, you will probably need hydraulic disc brakes. And I do
not mean the small kind made for simple bicycles.
I calculated the power it would take to climb some our steep hills. There are
other calculators on the internet, but they use metric.
Efficiency
pretty much doesn't change down to 80% max speed, may fall off
some at 60% max, and may for certain motors fall off up to 10%
at 30% max speed. That means if the bike can go 25 mph it may at most take a
10% efficiency hit if ridden at 7.5 mph (without pedaling). It also means that
if the bike can go 40mph, it will take about a 5% efficiency hit if ridden at
20 mph. 36V 20A at 10 kph. Efficiency about 42%. Switch to 11V custom
battery. Now at 10 kph, efficiency is about 72%.
Lower
voltage systems are safer, have easier BMS requirements (less channels), less
complexity, more compatibility (with DC converters and other components), and
easier on electrical components
Bigger
motors are not always better. the most important parameter to optimize in a
motion system is torque. If you have an application that requires high torque
at slow speed, a gear reduction of some sort can sometimes dramatically reduce
the motor size or increase the motor's efficiency. If you need
high speed at low torque, a large motor can have excessive iron loss.
This will manifest itself as a high no-load current. If you notice that the
no-load current goes up dramatically with speed, then the motor probably
has a lot of eddy current loss. If the no-load current remains the same over
its RPM range, the iron loss is mostly attributable to hysteresis drag torque.
Knowing what components make up the iron loss is important because it can point
you in two different directions: 1. reduce the frequency (RPM) of
the motor to reduce the eddy current loss or, 2. reduce the size of
the motor to reduce the hysteresis drag.
A
well designed motor and proper gearing would eliminate heat as a
problem... my current Unite motor never gets hot because I downshift when
it's in that "bad heat" zone and so it never needs to do "bad
things" in "bad situations". People who use fixed gears deal
with heat because.... well... because you have no gears to prevent heat.
The majority of the heat that can damage the motor and controller comes from
the amps of current. By choosing a system that has higher volts, you can
achieve the same amount of power with fewer amps.
use this simulator to figure it out: http://www.ebikes.ca/tools/simulator.html
something like this could be built with pedals.http://www.thecartimes.com/plug-in-electric-tricycle-piet-plugs-away-green-comfort/
The
most important parts
Hubs
with cartridge bearings, the idiot bicycle industry has virtually
stopped making bearings with loose balls. And the last one I bought
no longer has parts available; like the cones! (never buy Shimano
hubs)
Wheels
built with rigid spoke configuration, when spokes move due to
looseness they are guaranteed to break. Heavy duty wheels
Hydraulic
disc brakes, it will take you much longer to stop in the rain
with so much weight that you need a motor. A double hydraulic
disc brake is the only way to go for 600 to 800lbs.
Proper
gear reduction for enough torque thrust to keep the motor form
over heating. Using a 20 inch drive tire will make this much easier
to achieve. And cheaper to find a heavy duty tire (16” moped is
20”O.D.)
How
to power a heavy Velomobile or Cycle-truck.
Velomobiles
can get a get an efficiency of 40 miles to 85 miles per kilo watt hour of
electricity. While it is easy to build a Vehicle light enough to get the really
high mileage number at a slow speed on flat land, try thinking about how to
power one that will hold two adults and 80lbs of cargo. Or a cycle-truck that
will not be heavier than 600lbs (total combined weight) that will be driven up
a 9% grade. We have worse hills but they are avoidable. If you think that is
bad do the numbers on the new electric cars! 3.7 per kWh is high mileage.
I think the main reason that there is not much knowledge about this kind of vehicle is no one knows how to build one.
Most people build only for speed, unfortunately if you’re in a wreck and you get blamed for it the cops have to send your vehicle to be checked out by a technician, to make sure it cannot be driven faster than the speed limit for this kind of vehicle. So your best bet is to have it registered as a moped, or a motor-cycle. Using only one motor you could gear the motor down to the 30 mph limit, if it is still powerful enough to climb your steepest hills.
I think the main reason that there is not much knowledge about this kind of vehicle is no one knows how to build one.
Most people build only for speed, unfortunately if you’re in a wreck and you get blamed for it the cops have to send your vehicle to be checked out by a technician, to make sure it cannot be driven faster than the speed limit for this kind of vehicle. So your best bet is to have it registered as a moped, or a motor-cycle. Using only one motor you could gear the motor down to the 30 mph limit, if it is still powerful enough to climb your steepest hills.
An
option you might consider is using a multiple Kw capable motor and using a
programmable controller to keep the total power running through the motor
within legal limits but still allow multiplying up the phase amps for torque
when hill climbing in the motors lower end.
For example let’s say you used a 4.5-Kw rated 72V high power scooter motor. Normally you would use a controller with such a motor that would allow for motor phase amps to reach nearly 200-Amps with a battery side Amp limit of 65-Amps or so. You would end up with an electric motorcycle that could really move.
For example let’s say you used a 4.5-Kw rated 72V high power scooter motor. Normally you would use a controller with such a motor that would allow for motor phase amps to reach nearly 200-Amps with a battery side Amp limit of 65-Amps or so. You would end up with an electric motorcycle that could really move.
For
a lower total power build, within e-bike legal limits, you still use the same
motor and still use a large powerful controller that can handle phase amp
multiplication. One that goes all the way up to the that 200-Amp level when the
motor gets bogged down when climbing a hill, to get the full torque. But if you
program in a much lower Amp limit on the battery side, thus ensuring you stay
within legal total power limits, you still get the bottom end torque. Also you
don't need a great big battery that can handle sustained 65-Amps pull on the
battery end.
My state the legal power limit, for it to still be a Moped bicycle by the letter of the law is "2-brake-horsepower maximum" which is equivalent to 1.49-Kw physical output power. "Brake-horsepower" defines a motors physical output power not the electric power input. Thus in my situation I would examine the motors performance graphs and figure out what battery-side amp limit I should program in, to ensure that I stayed within that limit (knowing the general performance curves of such motors on a 72V system that would probably end up being about a 25-to-30 Amp limit on the battery side).
Basically use a much bigger motor and controller and just dial down the Amp limit on the battery side and thus tapper off the middle to the top band of the motors performance but still keep all, or nearly all, of the high torque capability of the bigger motor on its bottom end.
My state the legal power limit, for it to still be a Moped bicycle by the letter of the law is "2-brake-horsepower maximum" which is equivalent to 1.49-Kw physical output power. "Brake-horsepower" defines a motors physical output power not the electric power input. Thus in my situation I would examine the motors performance graphs and figure out what battery-side amp limit I should program in, to ensure that I stayed within that limit (knowing the general performance curves of such motors on a 72V system that would probably end up being about a 25-to-30 Amp limit on the battery side).
Basically use a much bigger motor and controller and just dial down the Amp limit on the battery side and thus tapper off the middle to the top band of the motors performance but still keep all, or nearly all, of the high torque capability of the bigger motor on its bottom end.
You do not want not to add speed to a 600lb vehicle. One of these motors can pop a bicycle drive chain easily. You will need a “Cycle Annalist” to help control the vehicle. And a controller that will read the Cycle Annalist. And at 600lbs with a speed of 30 mph, you will probably need hydraulic disc brakes. And I do not mean the small kind made for simple bicycles.
I calculated the power it would take to climb some our steep hills. There are other calculators on the internet, but they use metric.
Efficiency
pretty much doesn't change down to 80% max speed, may fall off
some at 60% max, and may for certain motors fall off up to 10%
at 30% max speed. That means if the bike can go 25 mph it may at most take a
10% efficiency hit if ridden at 7.5 mph (without pedaling). It also means that
if the bike can go 40mph, it will take about a 5% efficiency hit if ridden at
20 mph. 36V 20A at 10 kph. Efficiency about 42%. Switch to 11V custom
battery. Now at 10 kph, efficiency is about 72%.
Lower
voltage systems are safer, have easier BMS requirements (less channels), less
complexity, more compatibility (with DC converters and other components), and
easier on electrical components
Bigger
motors are not always better. the most important parameter to optimize in a
motion system is torque. If you have an application that requires high torque
at slow speed, a gear reduction of some sort can sometimes dramatically reduce
the motor size or increase the motor's efficiency. If you need
high speed at low torque, a large motor can have excessive iron loss.
This will manifest itself as a high no-load current. If you notice that the
no-load current goes up dramatically with speed, then the motor probably
has a lot of eddy current loss. If the no-load current remains the same over
its RPM range, the iron loss is mostly attributable to hysteresis drag torque.
Knowing what components make up the iron loss is important because it can point
you in two different directions: 1. reduce the frequency (RPM) of
the motor to reduce the eddy current loss or, 2. reduce the size of
the motor to reduce the hysteresis drag.
A
well designed motor and proper gearing would eliminate heat as a
problem... my current Unite motor never gets hot because I downshift when
it's in that "bad heat" zone and so it never needs to do "bad
things" in "bad situations". People who use fixed gears deal
with heat because.... well... because you have no gears to prevent heat.
The majority of the heat that can damage the motor and controller comes from the amps of current. By choosing a system that has higher volts, you can achieve the same amount of power with fewer amps.
use this simulator to figure it out: http://www.ebikes.ca/tools/simulator.html
 something like this could be built with pedals. |
| http://www.thecartimes.com/plug-in-electric-tricycle-piet-plugs-away-green-comfort/ |
 |
| http://wildnaturesolutions.com/ |
Gear calculations
Bicycle gears
Pulley diameters and speed
First stage gear reduction:
Motor-pedal
hybrid design
If
you live with steep hills and want to drive a more than the usual
bicycle-weight up them, you really need to put some thought into how to
motorize the machine. Some people think that all e bikes do not last long,
because most of them are designed for light weight duty on virtually flat land.
Hub
motors are the most efficient, but not for this scenario. Climbing hills at
legal speeds up steep hills with only one gear, is hard on a motor and
controller. Even if electric motors do have a much wider range of ability than
gasoline motors.
So
most people build for momentum, that takes calculation. Or just a reasonably
low gear on the drive wheel, and possibly a larger than legal motor.
The
federal government says that one horsepower should be the legal limit, but in
the state of Washington 1.2 hp is OK. Most people I know, chant the phrase “the
cops don't care”. But when I asked the cops in Seattle they told me how they do
care, and how they deal with it.
In
Europe the cops are allowed to have road blocks and do any thing they want to
keep the people from using a motor bigger than one-third horse power. That is
almost impossible to drive even one person, with out cargo, up a steep hill.
It
is possible to use more than one motor, see the white trike car above with two
or three hub motors.
Geared
hub motors are available in 5-1 gear reductions or less. When I calculated for
a 30 mile range velomobile, I had to use a 6-1 gear reduction because lead acid
batteries are very heavy. Better to use lithium. The price works out to be a
little less than lead acid over the life of the battery.
 |
| geared hub motor |
If
it is true that electric motors must spin near peak efficiency RPM to get full
horse power and that you need a very large gear reduction to allow the
motor to spin that fast and still keep the vehicle down to a legal speed. Then
most e-bikes are illegal.
For
high torque at low speeds you'll need a motor and controller that can allow
high amperage at slow hill climbing speed. If you get a programmable controller
you can limit the power to legal levels.
Or just use a vary large gear reduction for the high speed motors that run cooler than slow speed motors. like the Astroflight motors
Or just use a vary large gear reduction for the high speed motors that run cooler than slow speed motors. like the Astroflight motors
 |
DaVinci
drive unit
|
You then ask two questions:
Is acceleration in constant torque region enough for every use of the vehicle?
Is constant power region and max rpm enough to give an adequate top speed?
If the answer to both questions is yes, then a 1 gear transmission is enough. Otherwise, the vehicle can benefit from gears. Then you get to choose whether to use a gearbox or to change the electrical system.
Is acceleration in constant torque region enough for every use of the vehicle?
Is constant power region and max rpm enough to give an adequate top speed?
If the answer to both questions is yes, then a 1 gear transmission is enough. Otherwise, the vehicle can benefit from gears. Then you get to choose whether to use a gearbox or to change the electrical system.
“In normal mode, or the constant torque region,
the motor exerts constant torque (rated torque) over the entire speed range
until the rated speed is reached. Once past the rated RPM speed of the motor,
the torque will decrease proportionally with speed, resulting in a constant
power (rated power) output. The constant power region eventually degrades at
high speeds, in which the torque decreases proportionally with the square of
the speed.”
The ‘Cycle
Analyst’ maybe able to control the speed with out eliminating the slow
speed amps. But there may still be a chance you could burn out your power
system if you run too many amps through it at too low of a speed. A heat sensor
could be good.
If 3 to 7 years life span is long for a big hub
motor, then forget them.
(For Life expectancy, hub motors could work 5000
hrs without damage in Lab.
In real life it depends on the motor's usage (e.g. hitting bumps and water getting in).
In real life it depends on the motor's usage (e.g. hitting bumps and water getting in).
You can make a good heavy-duty motor like the
brushed Mars 909 last twenty years if you do not over power them with a cheap
controller.
One other thing to consider is
that if your motor nameplate says 1200W, that's the electric power it
draws. Its actual output will be less, possibly considerably less depending on
the motor design.
How to calculate a fixed gear
First measure the average grade of your worst hill. Use a carpenter level and a metric or 'tenths of inch' ruler.
And divide the span by the rise to get the percent
of grade.
Decide what the total combined weight of your
machine will be. Include every thing!
Then use this calculator to find how much energy
it takes to climb your worst hill, as a 'streamlined trike'.
Find a gear ratio that will bring the drive wheel
RPM down close to the legal speed limit (or what ever you can live with) when
at the wattage you need to climb the nasty hills. See graphs provided by
manufacturer. (this motor should have enough torque for any hill)
Decide what you think maybe a good sized pulley
for the motor, you may have to rethink the size later. Divide the diameter into
the size of a larger pulley on the drive wheel.
use this simulator to figure it out: http://www.ebikes.ca/tools/simulator.html
When using a rim sheave the belt may slip! Especially in wet weather! Unless you add something inside the rim like matte textured electrical tape or ridges some how.
To use a Gates power grip belt 8mm pitch GT3 down load the manual and rack your own brains to find the parts to fit together to get a close ratio to slow your drive-wheel down far enough! It will be easier to find a large belt pulley for a 20” wheel than any larger wheel.
Look for a
"One-Way Locking Bearing"
to make a ratcheting pulley.
 |
"One-Way Locking Bearing" |
Trapezoidal or square drive Timing
Belts??
A thin section belt may be the best, whereas the
pitch change at the periphery would be quite small
This should be ratcheting so
it will eliminate the drag of the motor when just pedaling
 |
| get the pulley at the same time your finding the length you need. |
.jpg)
Trike stability
Delta trikes and quads need a differential to use a single stage reduction; unless you can live with a lopsided traction drive (but that can push the nose of a delta trike to one side on wet hills).
Two-wheel positive traction can be had with a jack shaft, but will need a two-stage reduction. Delta trikes also have a tendency to roll over on a fast turn. The only thing that can be done for that is to weight down the rear wheels and lower the seat, then slow down.
A tadpole trike can spin out of control if the rear wheel is too close to the front and may be forced into a spin by too much weight on the rear; don’t use slick tires. But if the rear wheel is farther back it will need more weight to keep a grip on the road in an emergency stop-turn. In line tandem tadpole trikes probably will not have this problem. But the front wheels of heavy tadpole trikes should be built with the spokes all the same length to handle the lateral forces.http://commutercycling.blogspot.com/2007/10/trike-wheels.html
Low seats help keep trikes from flipping over, but they could still use a crash cage even if just to climb out of the seat.
Wheels should have at least 36 14-gauge spokes, 20" wheels with box wall rims are stronger than big wheels, although there have been good results from using the new tubular rims with only 32 spokes for downhill racers (jumping off cliffs).
Tires are a problem for this much weight. High pressure tires are essential but will give you a rough ride. I have a lot of expensive tires split down the middle. Maybe Moped tires?
Brakes are the most important thing
Only hydraulic disc brakes can be synchronized perfectly, but a double lever is not available, except for the Magura BIG brakes: http://www.greenspeed.com.au/magura.html
But you will still need a third brake on the rear wheel with extra-large rotors.
Drum brakes modulate better and give you more control over stopping than cable pull disc brakes, but are available only in cable pull and are no good in the rain.
 |
| http://www.bikerumor.com/2011/09/24/gatorbrake-eight-piston-hydraulic-disc-brakes-with-carbon-fiber-rotors/ |
 |
| http://www.singletracks.com/blog/mtb-repair/hydraulic-disc-brake-service/ |
Moped laws of Washington state says that you can't have more than
2 Brake Horsepower
Actually I don't know if it is possible to build
one of these that is perfectly legal unless you can keep the weight (450lbs?)
and speed down to about so the brakes work like they should.
'Build your own electric motorcycle' by Carl Vogal. I think people who lust for speed should be building electric motorcycles.
When the center of weight is so far
forward, it is possible to drop your feet, and have them dragged under the
front axial. It is much safer to have the crank behind the front wheels.
Note that the crank should be behind
the front wheels. But the front wheels should also be wider apart.
 |
| This one could use three hub motors |
 |
Dynamic
Stability
When a vehicle is said to be dynamically stable it is meant that it reacts safely and predictably under various driving conditions.
When designing a chassis, we can choose how the car will react when turning too fast. One of two things will always happen: either the car wheels will slip relative to the ground, or the vehicle will tip over. Obviously, slipping is the desired outcome. Keep this in mind for the moment.
When the car does slip out of control on a fast turn, we can design it in such a way that we know whether the front or rear wheels will slip first. This is important because if the rear wheels slip first, the vehicle runs the risk of spinning out of control (oversteer). If the front wheels slip first (understeer), you won’t spin out and it is easier to regain control. Understeer is considered a safe dynamic response to slipping in a turn and is designed into all commercial cars. Which wheels will slip first is a simple matter of weight distribution and weight transfer.
The problem for delta vehicles is how to distribute their weight and control their weight transfer during a turn to avoid undesirable outcomes. If you design the weight distribution for a heavy front bias to achieve understeer, you increase the risk of tipping over. If you increase the weight distribution on the rear tires, the vehicle will oversteer in hard turns.
We also need to consider nose diving, which is exactly what it sounds like. When you slam on the brakes as hard as possible, the vehicle will either skid to a halt or the rear wheels will lift off the ground. This is also a function of weight distribution and weight transfer. It would seem that the delta design has an advantage here because it naturally lends itself to having a rear biased weight distribution. But in the real world, a hard stop doesn't always occur when traveling in a straight line. If you stop hard enough while turning with a delta vehicle, the weight will transfer to the front wheel enough (despite suspension designs to prevent this) to cause the vehicle to flip over at an angle.
Keep a good 30% of the vehicle weight on the drive wheel to
maintain good traction. (Ideally 33/67 rear weight
distribution)
No comments:
Post a Comment