I hate talking to people about how to motorize a pedal powered vehicle! The just do not understand that any motor (especially electric ) must spin at peak efficiency RPM to get full horse power (see the label on the motor) 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.
All power assist e-bikes are geared too high for steep hills and full cargo weight!
Everyone knows that hill climbing works best in a low gear, yet people still use momentum ( and not enough of it) which puts more strain on the motor and batteries so that they do not last long.
This research was done for a micro vehicle that will replace a very small car, it will weigh around 500lbs fully loaded (children, tools, cargo). It will need to climb the very steep hills of the pacific northwest.
Peak efficiency
Series wound motors have a peak efficiency rpm, when powered past that rpm the efficiency goes down sharply and they start stressing out ["A brushed series wound motor becomes extremely hot with as little as 10% over gearing"]. With a single gear configuration it is easy to know what the motor’s RPM is by the speed, if you know what that peak efficiency speed is. It would be better to use a tachometer if you can get one. Actually an ammeter with a volt meter is even more important.
Cheap controllers and batteries can burn out if under sized for the maximum current flow.
Heavy vehicles on steep hills need batteries with a high discharge rate, not cheap lead acid gel batteries. http://endless-sphere.com/forums/viewtopic.php?f=2&t=19368
Gear reduction: Calculate wheel speed needed then find ratio of gears:
Wheel diameter x pi x motors peak efficiency RPM ÷ 12”per foot x 60min. ÷ 5280ft per mile = wheel speed without gear reduction ÷ 15mph = ? to 1( gear reduction needed.)
A 20” drive wheel maybe needed for a single stage reduction, or a sheave made from a wheel rim on bigger wheels.
AC induction motor controlers are the most advanced systems, and should be used if at all possible. http://www.electric-cars-are-for-girls.com/ac-motor-controller.html
http://endless-sphere.com/forums/viewtopic.php?f=2&t=29754
Hub motors cannot use 12 volts because the thickness of the wire needed for the higher current will not fit through the axle, if you find one please let me know about it. 48-volt motors are not more efficient than using lower voltage. The reason that people say that high voltage is more efficient than low, is that high speed is more efficient than low. High voltage is like a high gear, and is not efficient when climbing hills that need a lot of torque. Low voltage = low speed = high torque. However a huge gear reduction could have advantages, like a smaller motor:
http://endless-sphere.com/forums/viewtopic.php?f=1&t=29364
http://endless-sphere.com/forums/viewtopic.php?f=28&t=29429&p=424677#p424677
http://endless-sphere.com/forums/viewtopic.php?f=28&t=29648
Brushles motors do not over heat as easily as series wound brushed motors and they have a wider range of peak efficiency ie: a wide range of speed variance under stress. And they are aprox. 5% more efficient (at twice the price of the mars 909 series wound, what a deal!?). So if you can find one that will work for you it may be worth the larger price.
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The less the voltage the slower the but it will increase the amperage. Most electric motors can’t be run on 12 volts because the windings can’t handle the increased amperage of the lower voltage. So they may need a two-stage gear reduction.
Geared hub motors use three large expensive to replace planetary gears that waste enough energy to make a single gear reduction worth the extra thought, and low range of speed variance.
Internally geared hubs need regular maintenance and should be sealed enough to hold an oil bath.
I do believe that gearless brushless hub motors may be the best kind of motors for light weight bicycles. I just wish I could find a chart telling exactly what they can do in terms of 'weight-gradient-speed'. http://endless-sphere.com/forums/viewtopic.php?f=1&t=26176&p=378574#p378574
I believe that if you do not limit the speed electronically to 20 mph, your vehicle will be illegal. And if you are in a wreck using an illegal vehicle you will get the blame even if it is not your fault.
http://endless-sphere.com/forums/viewtopic.php?f=7&t=23357
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 would be good.
http://www.ebikes.ca/drainbrain.shtml
This is the motor to use http://www.cloudelectric.com/product_p/mo-4bb3995.htm But you may have to gear it down to 15 mph or even less.
I think that the Mars 909 would be better, but it's a bit past the legal point.
http://www.cloudelectric.com/product_p/mo-ptx-0909.htm
Bicycle drive chains are not strong enough; I tore two bicycle chains with my unassisted legs last year. So motor cycle chains or automotive belts are best unless you can just not accelerate hard enough to destroy the a bicycle chain.
O
A good reason to use motorcycle sprockets is that you can change the size if you need a lower gear on your regular route's worst hill.
Problems with belt drives:
http://endless-sphere.com/forums/viewtopic.php?f=28&t=23418
Trike stability
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.
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?
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.
If you insist on using a bigger motor than 1hp like the mars 909 ( the name has changed)3000rpm x (3"/9") x (3"/12") x 2074.71 circumference x 60minutes x .621504 mi/km= 19.3mph
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