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I saw something that looked like a maze of gears and chains, but I know that a simple two stage reduction will do the trick.

A belt drive from the fisrt stage then a light motorcycle chain on the second stage. Sprockets bolted onto the spokes.

gearreduction.jpg


bigsprockets.jpg
 
keeping it no higher than one HP at 24 volts I need a hub motor that is maybe a 1 to 8 reduction?

I realize every one wants to move as fast as possible, but not me and my children. we just want to climb hills.

How can we get 1/4 HP at 12 mph?
 
heliolatrix said:
keeping it no higher than one HP at 24 volts I need a hub motor that is maybe a 1 to 8 reduction?

I realize every one wants to move as fast as possible, but not me and my children. we just want to climb hills.

How can we get 1/4 HP at 12 mph?
Click to expand...

The magic pie is probably EXACTLY what you're looking for.
The tall diameter and slow speed winding makes it a torque machine.
Run it on 24 volts in a 26" wheel and it will produce a nice and sedate 15mph or under.

It is a real stump puller on 8,000w, LOL.

On a low regen setting with an infineon controller ( 10A ), it has amazing regen braking as well - like putting a death grip on a 203mm hydro disc brake that never fades.

A motor with more torque would be the crystalyte 530x/540x, or the cromotor hubzilla. But you'd have something that's grossly expensive and overpowered for what you want to do.

I am 240lbs and built a 20" magic pie up for climbing pike's peak on >72v. It should work for you as a kid hauler just great on 24v.
 
Big rotor is one way to get there. ( up a hill) Small wheels is another, like 20". Motor drives the chain is another. Motor drives a low geared sprocket on the left side of the wheel is another. Those Ezip bikes do that, and climb quite well. Sound like a dental drill doing it, but they climb.

The way I like to do it is a slow winding. So this, http://www.methtek.com/2011/11/12/2810-26-rear-37/

Or this,
http://www.emissions-free.com/catalog/i22.html

is known to work. Run them at 36v though. The 2810 will only go 15 mph on 36v. But will have 1 hp.

You can ask cellman for an even slower 12t motor. The 10t will go 20 on 36v.

Strangely, the motor will not have more torque. It will have the same 1 hp as typical kits have. But it will be able to use that 1 hp at a slower speed, and it WILL get up the hills better, with better defined as the motor doesn't melt.

Best motor?, that would be a pie ( huge rotor) in a slow winding,( which you can't get to my knowlege), in a 20" rim.
 
heliolatrix said:
keeping it no higher than one HP at 24 volts I need a hub motor that is maybe a 1 to 8 reduction?

I realize every one wants to move as fast as possible, but not me and my children. we just want to climb hills.

How can we get 1/4 HP at 12 mph?
Click to expand...


You didn't mention the grade of the hills you need to climb however even a light person will need much more than 1/4 HP to climb a steep hill, say 10%, at 12 mph. If you have steep hills I'd reconsider using 24V and go with 36 or 48V instead. Also you mention "reduction" and "hub motor" in the same sentence and while geared hub motors do have reduction, usually 5:1, the direct drive variety as the name implies is 1:1.

BTW, A good tool to play with to evaluate hub motors is the simulator at ebikes.ca, I suggest you take a look.

-R
 
Couple things, dogman..

The 10T "torque" MAC motor does 20mph on 36v, and will exceed that when fully charged.
It also has a poor thermal path, so if you are hauling multiple hundreds of pounds, it will not do that great of a job. For a single rider, i'd recommend it all day.

The 2810 is a real good winding of 9C but i can see it struggling with multi hundred pounds of load. Optimally you do want a bigger motor.

The 12T MAC should hit approx 15mph, so it is an ideal MACm for sure.

Best motor?, that would be a pie ( huge rotor) in a slow winding,( which you can't get to my knowlege), in a 20" rim.
Click to expand...

There is only 1 winding of magic pie for all wheel sizes, and that is SLOW :). You know that motor does only 18mph on 36v in a 26" right? and slower per volt in a smaller wheel. I only get 42mph on 30S lipo ( 115 volts nominal ).

If you've read some builds here on the forum everyone complains about it being too slow per volt but never ever complains about the torque unless they're running the stock controller :lol:

It also sheds heat like a beast. I am actually actively trying to get it hot. I cannot get it hot on 72V full throttle up a 3 mile 3% grade. On 24V it will wonder if you are even putting power into it :lol:

Dogman you need to come out here and ride my monster pie.
 
Ok, looks like the pie is wound slower than I thought.

But still not as slow as a 2810, which barely makes 15 mph on 36v. I'da linked to the 12t mac, but I didn't see a page for it on the site. So I linked the 10t, and suggested the slower 12t.

I'm not clear if his kids are being hauled, or if he's got them riding with him. If he's hauling a pile of kids, he needs a mid drive,( drives the chain) not a hubmotor. Or maybe dual motor macs, or dual motor pies, Going 15 mph, but with 3 hp.

Definitely 1/4 hp 24v won't do anything for him.
 
neptronix said:
heliolatrix said:
keeping it no higher than one HP at 24 volts I need a hub motor that is maybe a 1 to 8 reduction?

I realize every one wants to move as fast as possible, but not me and my children. we just want to climb hills.

How can we get 1/4 HP at 12 mph?
Click to expand...

The magic pie is probably EXACTLY what you're looking for.
The tall diameter and slow speed winding makes it a torque machine.
Run it on 24 volts in a 26" wheel and it will produce a nice and sedate 15mph or under.

It is a real stump puller on 8,000w, LOL.

On a low regen setting with an infineon controller ( 10A ), it has amazing regen braking as well - like putting a death grip on a 203mm hydro disc brake that never fades.

A motor with more torque would be the crystalyte 530x/540x, or the cromotor hubzilla. But you'd have something that's grossly expensive and overpowered for what you want to do.

I am 240lbs and built a 20" magic pie up for climbing pike's peak on >72v. It should work for you as a kid hauler just great on 24v.
Click to expand...

You were doing fine until you put that 8kw number in there. Those spindly windings can't take 8kw, and for the few seconds you pushed it through the stator of a slow wind motor would be so far into saturation that it would essentially be a heating element.

The man wants hill climbing, so any solution someone mentions just put a smaller wheel on it and it will be better.


heliolatrix,

A good motor suggestion is an impossibility without more info. Max total load, max grade, and minimum speed desired under those conditions are needed, and unless you go for a mid-drive rig with variable gearing you have to build for that condition, because if you don't then the first time you run across such a hill that is long enough you will fry something.

John
 
John in CR said:
You were doing fine until you put that 8kw number in there. Those spindly windings can't take 8kw, and for the few seconds you pushed it through the stator of a slow wind motor would be so far into saturation that it would essentially be a heating element.
Click to expand...

Actually you'd be surprised. I can do that with 6kW for a good amount of time on a lower voltage..
I can tell i am not using all of it's power because at 120deg C, it doesn't feel like it's bogging down like a smaller motor would.

Just trying to make a point that it is a torquey motor capable of handling a lot of power. Realistically i'd not put 2000-2500w continuous into it for more than 30 mins. But that's still hauling up a 7% grade at 25-28mph with a fat rider... not bad... :)
 
Agreed, 8000w into just about any bicycle hub motor just means 5000w is made into heat, and at best 3000w is made into motion.

But the pie could still be a good choice, if fed 2000w. But we do need the info to say if you'll get what you need out of any bike hubmotor. You can feed em quite a bit, but it better be short when you do.
 
Methods has a bunch of front 26" wheel 9c 2810 winds. Super cheap too. That's what I got for my tandem build.

Run it on 36v 50amps and you should have no probably towing the family up hills.
 
I just built a bike with a 2810 from Methods. Here is my built thread.

http://endless-sphere.com/forums/viewtopic.php?f=4&t=39480&hilit=2810

Although I'm using close to 100volts, I'm trying to have speed and torque.

A low voltage set up on this like say 36v speed is around 22-24kph or 13-15mph.
If you need the power and not the speed, use 36v with no more than 70amps.
This equals approx. 2500watts. You'll need a good controller to do that.
Best to have 48v/50amp max and even better 72v/30amp max.
Always use a Cycle Analyst or equivalent to monitor your watts.
No reason to heat up the motor like a woman's curling Iron! lol :wink:

Volt x Amps = Watts

I'm trying to be kind to this motor, so no matter what voltage I use I adjust the amperage to = the wattage. I shoot for 2500 to 3000 max
and I go easy on the throttle. :)

What is nice about High Voltage/Low amperage set ups is the wire sizing is small on controllers/hub motors and high voltage/low amps flows easier down
a wire. :wink:

It's nice to see John mention the "SATURATION" ..... I'm just learning but I did know that there is a point where most of the watts will just turn into waste heat.

Although I haven't built a MID-DRIVE set up Yet....... there is something to be said about High RPM and Gear Reduction :D

Enjoy.....
Tommy L sends.... \\m//
 
So what you are saying is that running a motor at less than peak efficiency will produce less heat? Or are you saying that most people will run them over the prescribed RPM/ amps and burn out the motors?

Does that happen with brushless motors?

We plan to use a programmable controller to keep it from over amping/ heating.
Can you point us to a good controller for these hub motors? Like the magic pie?
 
We understand that a two stage gear reduction would be better than a hub motor for 250LBs of riders on a 9% grade but if we can’t make it fit hub motors sound good. But they are only available in 5 to 1 reductions?


Are there any brushless non-hub motors?

Or a two stage reduction KIT, that the pulleys could be changed to fit the reduction need?
 
https://www.cyclone-usa.com/

This may be an option for you. Although I hear people say there is lots of chain noise, it does offer your entire bicycle gearing for hill climbing.
Some swear by this set up. Read and research! :)


Tommy L sends... \\m//
 
heliolatrix said:
... for 250LBs of riders on a 9% grade...
Click to expand...

Still need info. 250lbs or riders, no groceries, ice chest, backpacks, dogs, etc? Also, at what minimum speed? With a given load climbing a specific load at a specific speed requires a certain amount of power. Depending upon the specifics some motors will be up to the task and others won't. The maximum condition has to be your starting point for a dependable build.

Imagine a single speed bicycle with you and your kids aboard. Now imagine that your legs never tire except all at once when the battery runs out, and multiply their strength several times. Your legs are now an electric motor, and as long as the fixed gearing isn't too steep everything is fine and dandy on the flats, but as soon as you throw uphill grades into the mix it's a whole different story and there are finite limits. There is a specific grade you simply won't be able to climb.

People around here try to exceed the limits all the time, and they pay a heavy price. That's fine for the guys for whom breaking stuff is all part of the fun, as is fixing it. It's not fine for the guy with a couple of kids aboard 10 miles from home with hills in between. :shock:

John
 
https://www.cyclone-usa.com/
I never could figure out what the gear reduction ratio is on this... it's not the same as your pedaling gears because the motor is moving at a very slow speed.

I am estimating the weight at 350lbs total combined...max?

I also want to slow the motor down enough to pedal, that's why I originally thought of using a small motor maybe one third to one half horse power, and reduce the speed to some thing I can pedal with... maybe 100 rpm?

Putting the chain on the opposite side from the sprockets.

Still sounds like the best idea. Even if I need to go to a machine shop. Too bad no one makes a kit like what I need.
 
Yes, that idea would work. Far from the first example we've seen here. Gear it so the motor spins at it's happiest rpm, that is to say not too slow, while you pedal along in your lowest gear. You'll get some assist, but believe us when we say you'll like it a lot better with 1000w, than you will with 150w.

If you use a motor rated to about 400- 500w, then run it with a controller of 36v 20 amps, you'd have power you will notice and like the bike a lot more. The non hub motor section is where you will find the guys who know what ratios your will need and that sort of thing. Here in the general section, you get me, the hub motor moron.

But even this moron knows this, 1/4 horsepower hubmotor and you are going to get nada from it. hubmotors climbing hills can waste so much wattage into heat that your 200w would produce 10 watts of assist and 190w of heat in a hubmotor when loaded that heavy up a steep hill. Chain drive, you could just gear it crazy low. You might have a top speed of 2 mph, but it would grind up the hill wasting only 40w into heat instead of 190.

Another way to look at it is like this. Since 2000 BC it's taken at least a small horse to haul a big guy up a steep hill. Why would it now take a quarter of that wattage to do the same work now? You need at least 1 hp, 700w or so.
 
You mean start with a full one HP or more and then as I slow down it will produce less HP....and more heat?

Thats why hub motors are only for light weight loads and almost flat lands?

ok I started one for the calculations:
http://endless-sphere.com/forums/viewtopic.php?f=28&t=39839
 
Putting the motor on the other side from the sprocket with a two stage reduction,
I want to crank no fast than 55 rpm at 12mph (321868.8mm)

With a 20” tire (254mm tire radius)

Is this math correct? And what would be a better way to do this?
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
(25mm/ 170mm crank arms) x (12 sprockets/ 52 highest gears) = 6.47 gain ratio
(321868.8/ 6.47) / (170 x 2 x pi) = 46.09 crank rpms at 12 mph?
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
(26822.4 x 12) / (254 x 3.14) = 403.56 rpm? Wheel speed at 12mph
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
So then what do I need to reduce the motor’s rpms down to something close enough to that rpm?

504 rpm is good for 15mph and a higher crank speed…..actually 100 rpm might be easier to get into the right gear but harder to slow the motor down to. And of course a cvt like a NuVinci would help.

http://www.youtube.com/watch?v=c9t_uQc-NQ0
 
What is the top speed you want to end up with? and what is the voltage of the battery pack you want to use?

Heres the 20-inch tire RPM-to-speed chart from the resources stickie:
20-inch tire
1 mph = 16.81 rpm
1 kph = 10.50 rpm

10 mph (16 kph) = 168 rpm
11 (18) = 185
12 (19) = 202
13 (21) = 219
14 (23) = 235
15 (24) = 252
16 (26) = 269
17 (27) = 286
18 (29) = 303
19 (31) = 319
20 (32) = 336
21 (34) = 353
22 (35) = 370
23 (37) = 387
24 (39) = 403
25 (40) = 420
26 (42) = 437
27 (43) = 454
28 (45) = 471
29 (47) = 488
30 (48) = 504
Click to expand...
 
Yes that's the general idea. Each motor, hub or otherwise, has a certian RPM it wants to run at, given a certain voltage. With just air friction, for a hubmotor not touching the ground we call it the no load speed.

Once you get on, of course there is a load. On the flat, it's not enough load to slow the motor down too much, and the motor continues to run at a reasonable efficiency. 60-80% is typical. But climb a hill too steep, particularly if your hill requires more wattage than you have to lift weight up the hill, and the motor stalls. Slowed to say 5 mph, a typical hubmotor will be sitting there barely turning, while the windings turn into a space heater and get hot enough to melt solder.

1/4 horsepower is just going to be pretty weak, which is why all the guys who buy 250 w hubmotors come here asking what it takes to climb a hill. Because at 250w, they can't climb much. Not unless they weigh less than 100 pounds.

But I never said all hubmotors are only good for the flats. I might say 250w hubmotors can't climb much.

The correct winding of hubmotor, fed 3000w, climbs quite well. http://www.youtube.com/watch?v=AfwdkfNZ7RQ&feature=plcp Now way this happens with 1/4 horse. Near the middle of the vid, at the top of the rock crawler road, my motor does finally stall. The grade at that point is about 20 degrees, degrees not percent. And at that point, it's quite hot. The easier hills though, are cake for this setup.
 
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