What is the strongest motor for hill climbing ?

[migueralliart]

Let's say you were to design a system around having a 48V battery and x amount of current. Lets assume the top speed is not as important as hill climbing.

Basics;
26" rim
220lbs rider
80lbs ebike (accounting for motor and battery)
ability to regen

I would think a slow wind will take hills all day long with the proper current but I'm trying to minimize burnt motors so what is essentially the motor you'd choose to climb (10-13%) hills all day long like a GOAT and still fits on a 135mm rear dropout with mega beefy torque arms. Note this motor should be easy to source even if it is retail.

Wanna hear your recommendations. Basically the reason I ask is because I'm doing some design work on a hardtail frame and would like to know the strongest options going with a 135mm. If I go with 150mm then the choices are a bit more expensive but stronger.

 

[SamTexas]

I don't know which one is the strongest. But I'm more than impressed with the 9C 2810. Its climbing ability (torque) is way more than my need.

There are hills in Florida?

 

[migueralliart]

I don't know which one is the strongest. But I'm more than impressed with the 9C 2810. Its climbing ability (torque) is way more than my need.

There are hills in Florida?

Haha nope there aren't any hills here but there are back home in Puerto Rico .

Anyway isn't a 9C 2810 similar to the DD hub that cell_man sells?

 

[SamTexas]

Not 100% sure. But I think the DD hub sold by cell_man is the equivalent of the 9C 2807 which is a faster wind and therefore less torque. I have both the 2810 and the 2807. The 2807 is about 30% faster (at the same voltage of course) but nowhere near the climbing ability of the 2810.

 

[John in CR]

If you want to tackle hills like they're nothing, then lose the fixation with 26" wheels or go to a geared hubbie. The DD motors are all too steeply geared in the big wheels. The different turn counts simply determine the speed at which you need to climb, because they don't change the gearing. How do you think a large guy like me lives in a mountainous country without burning up a single motor and never using a temperature sensor? The motors I used for 4 years are just a speed wind version of the H40xx series motor. I blasted up many 10-12% grade roads. It's not magic, just proper gearing, and that's only accomplished with a DD motor by using a smaller wheel size.

Do up a comfy recumbent or semi-recumbent so you can cruise all over PR. Doing an ebike that is different enough from a typical bike will help you let go of the 26" thing just like cars enabled people to let go of wagon wheel size diameters?

 

[migueralliart]

Well based off a 26" and 135mm dropout I would think the strongest motors (for hill climbing) would be;

DD:
MP3 (with external controller of course) & MP2
9C 2810 & 2812
Clyte HS3525 (not available)

Geared:
MAC 1000w 12T
BMC equivalent

I'm guessing cromotors and clyte 540x are all for 150mm dropouts

 

[SamTexas]

Don't forget the 9C 2812. It's has an even slower wind than the 2810. I have never used it though, so can't vouch for it.

 

[John in CR]

Turn count is not the same thing as lower gearing. It works a little better on hills only because it is wound for slower speed and proportionately less power is required to go slower up a hill.

Here's an example of what gearing does for you:
My daughter tackles mountain roads with up to 30% grades on her craptastic escooter that all we did was beef up the phase wires and give her about 50lbs of worn out Konions instead of lead. Sure she only weighs 110lbs, but the weight has to do with power not gearing. The motor itself is far less than a 9C and only has a 19mm wide stator. What make it work is the gearing, because the wheel is only 16" in diameter. With a motor that has a 35-40mm stator that little scooter would hall fat me up that same steep mountain road.

The whole wheel size thing is why the Chinese make electric scooters by the millions and virtually no electric motorcycles with the typically much larger diameter wheels. Ebikes work ok with DD's in the big wheels, but it's a huge compromise that gets fully exposed when you start climbing hills, so much so that even lightweight guys are putting big-ass motors on and still having enough heat issues that they feel the need to put temperature sensors in their motors.

 

[migueralliart]

I totally get your point and I agree about the efficiency of using smaller wheels and higher voltage.

The problem is when you try to make a product such as a bicycle frame you can't really expect people to like right away a bike that uses 20" wheels. It seems the 26" size has actually created a fixation like you say. If I were to design a frame it would have to be 26" and 135mm rear dropouts for the same reason. I would like to commercialize it to the DIY people and hope that maybe it will become a turn key solution. In my trike I use a 20" HS3540 and I totally get what you are saying about smaller wheels.

 

[davec]

i guess there's a few options
either a beefy clyte 5403 in 20"/ or a cro
2 DD 9c's
or maybe even a mid-drive with gears
i can name a few other dd hub motors but i have no idea how you'll fit it on a bicycle

 

[bowlofsalad]

Not 100% sure. But I think the DD hub sold by cell_man is the equivalent of the 9C 2807 which is a faster wind and therefore less torque. I have both the 2810 and the 2807. The 2807 is about 30% faster (at the same voltage of course) but nowhere near the climbing ability of the 2810.

Cell_man's DD hub comes in various windings, much like 280x series, different windings. His mac motors come with different gearing as well.

I think the problem with really high torque requirements concerning hub motors is that you are they very limited in top speed. I don't really know what would provide the most torque honestly. Maybe a mid drive, maybe a geared motor like the mac 12t. I imagine that regardless of what you go with, assuming the motor can handle the power, if you go with a high enough voltage pack paired with a high enough wattage battery (BMS maybe) and controller, you should have all you need to climb just about any hill. With enough gearing, a mid drive can have some pretty intense torque and speed.

 

[dogman dan]

Strongest motor would be the one that weighs 25 pounds and has a shitload of copper in it. One you can feed 3000w or more without a hiccup. cromotor, 5400, 5304, etc.

Idealy, you'd pick a winding of it that is not the extremely fast version if you are going to use 26" wheels.

For what you want to do, a 5304 would work great. I may be posting one for sale by late spring if you live in the USA. In Europe, there may be a 5305 still available if you look in the for sale used sect.

If Cellman can get slow windings of his dd motor for you, one of those would do your 13% grades with no problems. 2810 would go 19 mph on 48v. a 2812 you'd want to run on 72v, it's just too damn slow on 48v.

Or his Mac in 12t or 10t should work fine.



Re the windings, you don't get more torque from a slow winding. What you do, is overheat the motor less with the torque you get out of that particular motor. So say you are climbing 13% on a 9c motor, using 48v 22 amps. You get the torque you get from 1200w. No more, regardless of the winding you choose.

A 2807 will climb 13% at about 5 mph, about 15 mph slower than optimal speed, and more than half your wattage just makes heat. So call it 500w worth of torque. No torque because you stalled the motor.

A 2810 will climb 13% at about 13 mph, about 7 mph slower than optimal speed, and will only waste about 20% of your wattage into heat, so call it 950w worth of torque.

So as far as the rider can tell.... the slow motor has more torque. It can't have more than 1200w worth of it, but it sure can waste more of what you get if the motor can't keep up to speed. Since the motor is slow, it never gets as stalled as the fast winding does.

So that means there are three approaches to avoiding bogging down. One is gear down mechanically, with chain or smaller rim or something. Two a is slower winding, so that slower is not as far from the efficient rpm. And the last, is to just use a bigger motor and give it enough power to keep up the speed and never stall. Combine one and two for the win, and you have one of John In CRs bikes.

 

[motomech]

Going down to just 24 inchers on my mountain bike created pedal strike problems and required changing out the chain-ring set and bottom bracket, etc, etc.

Building a performance ebike to ride in the mountains of Central Puerto Rico would be a dream come true. I lived in Dorado Beach for a while and had a very nice Kymco 250cc scooter that I would ride up into the interior every chance I had. The nicely surfaced, wild flowered lined 1 and 1/2 lane roads that drop down into dark(Spanish moss covered) hair-pin turns, the light traffic, the incredibly cute little cottages, made form one of the best two-wheeler experiences in my life.
And I have been riding for over 50 years in the US, Mexico, Central America and the Caribbean.
But if I am ever lucky enough to go back to PR to retire, I think I would be inclined to custom build a 50 to 125cc sized electric or electric hybird scooter to ride in the hills.

But back to the original question, what about 2WD. There really isn't need to go much faster than 35 mph, so a pair of fast wound gear motors would be possible.
Something like a pair of 8T's on 50 to 60 Volts could hit that speed and still climb those roads well.
It's not like the roads I know there have climbs that go very long and the beautiful weather is nice and fresh.

 

[dogman dan]

Yeah, 2 hubmotors does the trick. I'm not sure if he wants to ride paved or trails, but I didn't like front hub on dirt. But 13% even on dirt is not so steep, and another hub on front should work fine. Then you could use any motor, and just blast it just as you would with one larger motor.


I've not yet done two motors for trails, because I don't like the weight on the front wheel in rocky terrain. And the 2812 has done me fine for the trails in my area. When I go to the real mountains though, I encounter 25 degree slopes on trails made for horses, and burn my motor.

 

[migueralliart]

I would LOVE to use john in CRs motor BUT it works on a 150mm dropout I believe. If I'm designing a frame maybe john can tell me if the motor can be laced ?

 

[el_walto]

I'm voting for the MAC 12T

 

[dogman dan]

10-13% is not that steep, though 13% will fail most typical 20 amps hubmotor kits. What do you want to climb, paved or dirt? Nothing wrong with front hubs on paved.

For dirt, a 5304 has worked for a long time, but I didn't like that much rear wheel weight myself. I preferred to climb slower, on less power or only in cold weather for more power, using the 2810 or 2812. 10 pounds less wheel weight worked better for me on really rocky trails.

For paved, on long tours nothing wrong with the weight of a 5304. I was thinking double motor on my longtail, but then found a good 5304 and jumped on it. But a Clyte HT plus a gearmotor on the front wheel is an interesting idea to me still. Run 1500w in the HT, and 800 in a bafang?

 

[migueralliart]

I'm voting for the MAC 12T

I though about the MAC as well. What would be the speed on the flats on 48v and a 26" rim?

 

[migueralliart]

Going down to just 24 inchers on my mountain bike created pedal strike problems and required changing out the chain-ring set and bottom bracket, etc, etc.

Building a performance ebike to ride in the mountains of Central Puerto Rico would be a dream come true. I lived in Dorado Beach for a while and had a very nice Kymco 250cc scooter that I would ride up into the interior every chance I had. The nicely surfaced, wild flowered lined 1 and 1/2 lane roads that drop down into dark(Spanish moss covered) hair-pin turns, the light traffic, the incredibly cute little cottages, made form one of the best two-wheeler experiences in my life.
And I have been riding for over 50 years in the US, Mexico, Central America and the Caribbean.
But if I am ever lucky enough to go back to PR to retire, I think I would be inclined to custom build a 50 to 125cc sized electric or electric hybird scooter to ride in the hills.

But back to the original question, what about 2WD. There really isn't need to go much faster than 35 mph, so a pair of fast wound gear motors would be possible.
Something like a pair of 8T's on 50 to 60 Volts could hit that speed and still climb those roads well.
It's not like the roads I know there have climbs that go very long and the beautiful weather is nice and fresh.

You sound like a person that understands what I'm talking about in terms of hills. The central part of the island has some steep slopes but like you say they are mostly short. The problem is I'm trying to target a do it all bike that I can market there. If I were to go with a MAC 12T or a 9C clone from cell man with the slowest wind possible and say go 15S that might do the trick. Thing is I would also want to know what would be the flat speed on those two. I'll get in touch with cell man.

Also that idea of the hybrid scooter crossed my mind a while ago. Unfortunately the electronics to make the motor charge the batteries are going to be somewhat complex and therefore not possible to do on a DIY scheme for a modest amount of money. But a hybrid scooter will be the BEST of both worlds it would be extremely economical there and here in the US. The low diameter rim will help with the inclines.

 

[sabongi]

duplicated

 

[sabongi]

I'm voting for the MAC 12T

I though about the MAC as well. What would be the speed on the flats on 48v and a 26" rim?

37km/h!
http://www.ebikes.ca/simulator/

 

[migueralliart]

I'm voting for the MAC 12T

I though about the MAC as well. What would be the speed on the flats on 48v and a 26" rim?

37km/h!
http://www.ebikes.ca/simulator/

I don't think that is a 12T.

http://endless-sphere.com/forums/viewtopic.php?f=3&t=38991&start=15#p569821

 

[gensem]

Mac @48v (16s lifepo4) using a 26" wheel. According to cellman site.
12t 34kmh
10t 40kmh
8t 48kmh
7t 53kmh
6t 58kmh

But i think i would use a cromotor if i was in your situation.

 

[John in CR]

A bike for sale is a completely different animal than a conversion kit for sale or an ebike fore yourself. Don't you have any rules you need to fit, or are you planning to sell it as "offroad only"?

China may put over 10 million new DD 2 wheelers on the road every year, but not in their mountainous regions. 2wd might be a consideration though.

 

[migueralliart]

A bike for sale is a completely different animal than a conversion kit for sale or an ebike fore yourself. Don't you have any rules you need to fit, or are you planning to sell it as "offroad only"?

China may put over 10 million new DD 2 wheelers on the road every year, but not in their mountainous regions. 2wd might be a consideration though.

If you go to PR you'd find there are people moving around in bicycles with engines and things like that most of em I've seen going more than 30mph. The only rule I'd probably have to obey is the 22mph one and even thou they don't pay close attention to bicycles. Perhaps it is better to market them as off road only like you said.

Dual DD is not an option the thought of going with 2 controllers and throttles is a big no no.