Electric Cargo-bike POWER system for steep terrain?

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Hugh-Jassman
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Electric Cargo-bike POWER system for steep terrain?

Post by Hugh-Jassman » Jul 25, 2017 12:13 pm

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I have put too much thought into how to build one the best way for living on steep terrain (9% average). But I am still looking for the best example. I maybe the only one thinking about how bad transportation is going to get.

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Living in the state of Washington I am restricted to a 1000w out put motor. And for 450 to 600lbs total combined weight, that is almost impossible. I figure I will need at least a 13:1 gear reduction ratio...for a 12-14 mph maximum.

And I believe that new motor technology is still going to be needed. Like vector control. What else?
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I found these guys that built a very heavy-duty frame, but then used a pair of hub motors. Totally not street legal in my state.
Is there a vector controlled hub motor that would do the job with only one?? I doubt it. But then maybe I could use just a controller with a smaller three phase motor, assuming I could find one.

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Last edited by Hugh-Jassman on Jul 29, 2017 12:25 pm, edited 2 times in total.

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Re: Electric Cargo-bike POWER system for steep terrain?

Post by Chalo » Jul 25, 2017 1:11 pm

Why can't you use two slow wind hub motors that deliver 1000W total? Mac motors are 500W rated, and a pair of 10t or 12t Macs would climb steep stuff nicely, even with a load.

A BBS02 or BBSHD set up for sub 1kW would do the job too, at the expense of increased maintenance compared to a hub motor.
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Re: Electric Cargo-bike POWER system for steep terrain?

Post by neptronix » Jul 25, 2017 1:43 pm

Vector control won't make horsepower appear out of thin air :) it is just a method of determining when to send power to a coil, and at what time, etc.
If you want to remain within the law, a mid drive is probably your best solution.

Motor technology really isn't your problem... how much horsepower or watts it takes to move a bike up a 9% grade is your problem.
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Re: Electric Cargo-bike POWER system for steep terrain?

Post by rumme » Jul 25, 2017 3:50 pm

You may be able to achieve your goals, by going to a very small moped styled rim hub motor of 1000 watts wound specifically for torque and lower top speed of 15 mph or so .

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Re: Electric Cargo-bike POWER system for steep terrain?

Post by Hugh-Jassman » Jul 26, 2017 4:42 pm

tell me more....like which motor? ...built into a 16"od wheel?

rumme wrote:You may be able to achieve your goals, by going to a very small moped styled rim hub motor of 1000 watts wound specifically for torque and lower top speed of 15 mph or so .

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power graph set up

Post by Hugh-Jassman » Jul 26, 2017 4:55 pm

Can anyone here tell me how to get the results I need by recofiguing these graphs? or did I do it wright???
The graphs don't tell me what the motor is capable of, so I don't know if it is possible to rig the motor do do this....



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so the trick of using two hub motors like this would certainly work if I set the controller to turn off at 1000watts...
can you guys show me a graph of what it would look like?



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rumme wrote:You may be able to achieve your goals, by going to a very small moped styled rim hub motor of 1000 watts wound specifically for torque and lower top speed of 15 mph or so .
Last edited by Hugh-Jassman on Jul 26, 2017 5:22 pm, edited 1 time in total.

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reduction ratio verses a small tire?

Post by Hugh-Jassman » Jul 26, 2017 5:06 pm

Is ther a way to calculate the difference in performance from a hub motor like the graphs abouve and a proper gear reduction? These graphs only go down to a 16 inch tire, so that is still a very small amount of gear reduction copared to a 26inch tire.

A 16” wheel is a ratio of 1.6¼ to 1 of a 26” wheel. (20” is 1.3 : 1)
Chalo wrote:Why can't you use two slow wind hub motors that deliver 1000W total? Mac motors are 500W rated, and a pair of 10t or 12t Macs would climb steep stuff nicely, even with a load.

A BBS02 or BBSHD set up for sub 1kW would do the job too, at the expense of increased maintenance compared to a hub motor.

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Re: Electric Cargo-bike POWER system for steep terrain?

Post by MadRhino » Jul 26, 2017 5:11 pm

Are they really checking ebike legal power where you live?

If so, build a mid drive. 1000 w is very little power to climb a load repeatedly, and taking advantage of gears is your best bet if you want to be legal.

My experience is that nobody cares about your real power. They care about how you ride, and that is the only reason why the police would bother you. My solution is building with a big hub and to feed a lot of power, making a very powerful and reliable bike that does require only minimal maintenance. Then, ride clever and never be bothered. Even if the police would check you anyway, a cargo bike does draw much more attention to its load than its power.
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Re: Electric Cargo-bike POWER system for steep terrain?

Post by dogman dan » Jul 27, 2017 6:35 am

Limited power and unlimited weight calls for mid drive for sure.

However,,, I run some bad ass, very long hills here in NM, with 2000w hub motors. Weight is limited, but to 450 pounds or so total weight. Meaning I can carry 100 pounds.

But, really,, is any body checking your watts? Just build to normal speed, and high wattage. Lower than normal RPM hub motors on 48v work. Not crazy slow, just not the higher rpm one.

If you do go hub motor,, 20 inch rim for the win, for sure. like the edgerunner. or my bike that burned my garage.
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Re: Electric Cargo-bike POWER system for steep terrain?

Post by zackclark70 » Jul 27, 2017 8:30 am

cyclone motor kit with better brackets and the right gearing will tow a car lol i would go with the 1680w if the law allows it wont be the fastest but it will take you up anything as long as you can hold on given the right ratio

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Re: Electric Cargo-bike POWER system for steep terrain?

Post by Hugh-Jassman » Jul 27, 2017 12:40 pm

I am amazed at how many people live in denial of the real probability of getting in deep trouble just because they don't know how to get around it except by ignorance.

Two of these hub motors would do the job, and a better efficiency than one. but I need to know how to engineer the system the best possible way.

I want to sell these in our state so it has to be perfectly legal, yes they do check up on what is being sold in stores, and underground selling is not a good option. Even if there is a conflict between the federal law and the state laws.

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Re: Electric Cargo-bike POWER system for steep terrain?

Post by teklektik » Jul 27, 2017 1:52 pm

Here's the simulation for dual MAC8T motors assuming equal sized wheels with identical controllers. As you can see the motors are out of the controller-limited region (after the peak inflection point of the red motor curve) and so are not bound by the controller amp rating and are running at near peak efficiency even though they are climbing a 9.5% grade. This requires about 54 battery amps which should not be difficult to achieve (you want to run a single battery - avoid the control and monitoring complications of using two).
EqualWheelMotorController2wdSimulation.png
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This is technique is essentially a graphical analysis that gives viable results given the constraint of equal sized wheels and identical motors and controllers:
  1. Set up for one motor/controller/wheel and run the simulation
  2. scrub the cursor until the required load power is twice the delivered motor power (2 motors, right?)
In the above example, you need 1600W to climb the grade and each motor will be loafing and supplying only 800W.

If you run equal wheels/motors/controllers you can use simple Infineon trap controllers and will get optimum efficiency under almost all circumstances using a single throttle with no special tuning. Recommend a CA3 to drive the two controllers to get throttle ramping and current throttle for smooth operation + 2WD PAS and/or autocruise if you wish... Since the drives are the same, you can use the CA to monitor the temperature of either motor and assume the other motor is about the same temperature. This gets you automatic thermal power rollback to avoid cooking the motors if you try to overtax them.
  • Remember, electric motor power specifications are in terms of 'rated power' not the actual power you run it at. So a 500W MAC can easily be run at 1500W although it will heat up and eventually overheat with this overrated operation. But legally, it's still only a '500W' motor. Do not be confused by comments about testing the output of a bike - the traffic statutes are written to facilitate field enforcement - so many cc's or so many rated Watts - not the actual hp output of a motor which an officer could not possibly measure. He needs to be able to make a decision based only a quick look at a motorcycle model plate or wattage sticker - hence the way the statutes are defined (of course there are some really confused state statutes out there, but that's another matter...)
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Re: Electric Cargo-bike POWER system for steep terrain?

Post by dogman dan » Jul 28, 2017 6:22 am

Well yeah,, 4000w ( controller potential combined) would do er. I think its been shown here time and time again, that two 500w rated motors given 2000 or more watts combined climbs like a bat out of hell. 3000w or so actual watts should do the job very nice.

I never personally explored the double hub motor thing though, because a single larger dd hub motor easily does all I ever needed with 2000w controller. 100 pounds of cargo up the rocky mountains. So I never got around to adding the second motor, did not need it.

What I did try to convey though, was that if power is limited to 1000w, then the mid drive wins every time for a huge load up a mountain.

One 8t,, I can cook off in the mountains easy, with 450 pound load. But two will work great, if you want to do the two motor thing. The experiment I always wanted to try, was a 500w rated DD ( like a 9c, pie, etc) in back, and a Mac 10t up front. The mac would have a push button throttle interrupter. so throttle would always give me 1000w from the DD. then on the hill, when the dd slows, mash the button and apply 1000w on the geared motor.

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Re: Electric Cargo-bike POWER system for steep terrain?

Post by Hugh-Jassman » Jul 29, 2017 12:15 pm

Wow that is an excellent explanation, thanks. But what is a CA3? 3000Watt??
Is this one possible, with a higher voltage and larger wheels?

I would really like to see a build thread on that one:

"One 8t,, I can cook off in the mountains easy, with 450 pound load. But two will work great, if you want to do the two motor thing. The experiment I always wanted to try, was a 500w rated DD (like a 9c, pie, etc) in back, and a Mac 10t up front. The mac would have a push button throttle interrupter. so throttle would always give me 1000w from the DD. then on the hill, when the dd slows, mash the button and apply 1000w on the geared motor."



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https://www.facebook.com/AnywhereBerlin/?pnref=story


This is as close as I could get the power setting
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Re: Electric Cargo-bike POWER system for steep terrain?

Post by markz » Aug 06, 2017 4:08 am

Reminded me of a e-skateboarder blasting past me on my wimpy ass conhismotor so called 1500W kit P.O.S.
up a hill
Geared motors is the way to go for load hauling and hills. Or better yet, mid drive.
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Re: Electric Cargo-bike POWER system for steep terrain?

Post by MadRhino » Aug 08, 2017 8:02 am

Geared motors are easy to push to fail. They are good for low power, low speed, low weight, no hit, no jump. Too many enclosed parts. Too weak clutch. Poor heat dissipation.

Mid drives are good at both ends of power usage. Bicycle mid drives can't take much power, custom or motorcycle mid drives can be built higher power than a hub can survive. In the middle, a hub build is simpler and more reliable.

Stoke monkey (using a hub motor as a mid drive), is either limited by the drive train or much heavier when built with a robust drive train. Cooling is an issue that need to be solved if it is fed high power, because a hub doesn't shed the heat as quick when it is not in a wheel. Yet, it is the only good mid drive solution in between bicycle and motorcycle power.

Climbing is not a problem with a big hub that is fed enough power that it doesn't lag. It is only a matter of matching wheel size and motor winding for the speed that you ride. Even big hubs have their limits, but few conditions are not possible to solve with a rig that is specific to them. A big hub is reliable and doesn't require much maintenance. If you ride far in the wild with any mid drive, you better be carrying a complete tool kit and spare parts for it.
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Re: Electric Cargo-bike POWER system for steep terrain?

Post by markz » Aug 08, 2017 3:03 pm

Hill climbing with a low turn count direct drive motor and a smaller diameter wheel.
Low Turn Count - Allows you to push more amps through the windings, because the winding wire is larger and shorter.
Small Diameter Wheel - Keeps the motor cool, adds more torque but reduces top speed.

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Re: Electric Cargo-bike POWER system for steep terrain?

Post by dogman dan » Aug 09, 2017 6:24 am

That is the John in CR solution, and it really does work!

You just don't need the high turn count, when the wheel is very small, less than 20", and the load is not huge. Works even better if the motor can handle 2000w, or you have two that can handle 1000w each.

But once you started to mention selling them, and needing to comply with state laws, you really did just decide to go mid drive, or face a fairly low load limit.

Why? Because however you do it, 1000w has a definite limitation in the load it can haul up a hill, even with a small 20" wheel. You will hit the load wall at right about 400 pounds, when the grade reaches 8% or above. Geared motor, DD motor, whatever, it will start to really slow down if 1000w is all you have. So it will have to be geared even lower, to handle bigger loads than 400 pounds. That's 400, rider, bike, cargo, battery. You are most likely wanting to build a bike able to carry more. this means mid drive.

An illegal bike, two 1000w motors will get up the hill with a big load easy. Like two of the macs. Your last sim chart shows a mac running 1600w. You betcha two of that will do the job beautifully. But its not legal most states.

I see no huge advantage to two motors, if you limit total wattage that low. Time to overheat will be less, but up any steep hill loaded to 400pounds or more, the motors will be turning very slow, and overheating. even in 20" wheel. You might be better off to just run a standard wind dd in 20 inch wheel in that situation, if you insist on a hub motor. ( of limited wattage high load)

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Re: Electric Cargo-bike POWER system for steep terrain?

Post by fechter » Aug 09, 2017 8:42 am

9% grade is going to be tough with a heavy load. Either you need a very high powered hub motor or a mid-drive. If the grades are short so the motor doesn't have time to overheat, the hub motor might be OK. Mid drives are good if you want to climb a steep hill without using illegal power levels since you can change the gearing. I have been super impressed with the climbing ability of my BBSHD drive.
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Re: Electric Cargo-bike POWER system for steep terrain?

Post by wineboyrider » Aug 09, 2017 8:53 am

fechter wrote:9% grade is going to be tough with a heavy load. Either you need a very high powered hub motor or a mid-drive. If the grades are short so the motor doesn't have time to overheat, the hub motor might be OK. Mid drives are good if you want to climb a steep hill without using illegal power levels since you can change the gearing. I have been super impressed with the climbing ability of my BBSHD drive.
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Re: Electric Cargo-bike POWER system for steep terrain?

Post by Triketech » Aug 09, 2017 10:06 am

Direct Drive Hubmotors are not very efficient at low speeds, as shown on the simulators. In the real world with average speeds at 10 MPH or less, and steep climbs with a heavy bike, the same route on a Magic Pie may consume nearly twice the power a Bafang Mid Drive would consume.

Take a 400 lb bike up a 9% grade at 9 MPH, just the ascent takes 500 watts, on top of about 100 watts of normal resistance. Look at the efficiency level of the motor chosen at those speeds.

As far as a hubmotor, the MAC 12T would probably be a best choice with this exception; gear and clutch life may be compromised a bit under those loads.

If it were my choice, I think I would go with a BBS02, 8 speed all steel drivetrain, with a wide ratio cassette.

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Re: Electric Cargo-bike POWER system for steep terrain?

Post by markz » Aug 09, 2017 2:53 pm

Cyclone would be my choice over the BBSHD, just because of the various power options.
But either one is a great choice, and I'd choose mid drive over direct drive hub motor.

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Re: Electric Cargo-bike POWER system for steep terrain?

Post by Chalo » Aug 09, 2017 4:09 pm

markz wrote:Cyclone would be my choice over the BBSHD, just because of the various power options.
But either one is a great choice, and I'd choose mid drive over direct drive hub motor.
He said his local power limit is 1000W. In that case, Cyclone has drawbacks but not advantages over BBSHD.
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Re: Electric Cargo-bike POWER system for steep terrain?

Post by MadRhino » Aug 09, 2017 8:52 pm

I doubt that one can climb 600 lbs in steep mountain trails with legal power, not reliably. Then, there is no such thing as legal power in mountain trails. For the street, a 3 speed switch should do it. The weight is enough to require a motorcycle chain for a mid drive to be reliable up the mountains or riding rough trails.
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Re: Electric Cargo-bike POWER system for steep terrain?

Post by Chalo » Aug 09, 2017 10:25 pm

Where I live, pedicab drivers climb steep city streets with up to 1000 pounds gross, on muscle power alone. If you can't do it on a single bike with 1000W of motor power plus muscle power, well....
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