Fast long-range cheap tourer[emoji2]

Mike_S

Mike_S

1 mW
Joined
Dec 20, 2012
Messages
17
Location
Athens
Hi I know that all the above don't go together but let me explain.
I want to make an e-tourer on a GT hardtail, cromoly frame.
I want to be able to travel 100 km at a time, at 50 km speed, with continuous pedal contribution of 130-150 Watts from me constantly.
I was thinking C-lyte HS3540 or 3548 but are there better options nowadays? Something lighter? I am thinking 1-2 kw hub motor.
Also what controller do you propose.
(Would love Bluetooth connectivity)
And what battery? Thinking 52V 14Ah.
MTB will be transformed with road tyres (26X1.3) and possibly road bars for more aerodynamic position.
Thanks

Sent from my Mi MIX 2 using Tapatalk

 
A 1000w motor will get you to 50km/hr but in order to be able to input 130-150w on the human end you will need to have a pretty high gear ratio available. I would say at the least a 50/11 depending on the wheel size.

However range wise at that rate of speed, even with your projected human input, you will be burning about 50wh's/km on level ground. Which as noted means a pretty pricey battery that will also add more weight to get to speed and keep there increasing wh/km consumption.

Maybe it's just me but based on my life long cyclist/motorcyclist experience I find that I am more comfortable going 200km/hr on a motorcycle than 50km/hr on my ebike for any length of time. I don't own a moto anymore but if I needed to meet your requirements that is the first option I'd consider.
 
Mike_S said:
Hi I know that all the above don't go together but let me explain.
Click to expand...

The title made more sense than the explanation. How would you feel about cutting the speed in half? At 50kph, it won't really matter how hard you pedal. At 25kph a real athlete would stand a good chance of doing it without the motor, and that's where you need to be to pull this off. The ebikes.ca site seems to be out of commission right now and the simulator with it, but I believe with a normal range pedal input you could expect to use at least 250W - just motor, not combined. Check my math:

60 km / 25kph = 2.4 h

@ 250W = 600 Wh

14Ah x 52V = 728 Wh

... so it looks reasonable on paper. You won't really get the whole 14 Ah, of course, could be much less. 40 kph will more than double your motor drain, and I bet 50 kph will quadruple it. Wind resistance is a major factor at higher speeds.

My theory is that for a tourist the key is not "how powerful a motor do I need", but "how light can I make this". The ordinary bicycle is a good match for touring, and a reasonably big motorcycle is also. Battery powered solutions are more awkward for long distances, and you can't really afford to build an electric motorcycle with a 100km range, but maybe you can add a light electric boost to a bicycle without going into the red on combined human/battery range.
 
I find it easy to build an ebike that is a comfortable ride at 50, even much faster, but not on a budget. The longer you ride, the faster your top speed, the more time and money you need to spend on your build.
 
donn said:
Mike_S said:
Hi I know that all the above don't go together but let me explain.
Click to expand...

The title made more sense than the explanation. How would you feel about cutting the speed in half? At 50kph, it won't really matter how hard you pedal. At 25kph a real athlete would stand a good chance of doing it without the motor, and that's where you need to be to pull this off. The ebikes.ca site seems to be out of commission right now and the simulator with it, but I believe with a normal range pedal input you could expect to use at least 250W - just motor, not combined. Check my math:

60 km / 25kph = 2.4 h

@ 250W = 600 Wh

14Ah x 52V = 728 Wh

... so it looks reasonable on paper. You won't really get the whole 14 Ah, of course, could be much less. 40 kph will more than double your motor drain, and I bet 50 kph will quadruple it. Wind resistance is a major factor at higher speeds.

My theory is that for a tourist the key is not "how powerful a motor do I need", but "how light can I make this". The ordinary bicycle is a good match for touring, and a reasonably big motorcycle is also. Battery powered solutions are more awkward for long distances, and you can't really afford to build an electric motorcycle with a 100km range, but maybe you can add a light electric boost to a bicycle without going into the red on combined human/battery range.
Click to expand...
But I already do 27 km/h over 2.5 hours without the motor. What is the assist that I should anticipate?

Sent from my Mi MIX 2 using Tapatalk

 
MadRhino said:
I find it easy to build an ebike that is a comfortable ride at 50, even much faster, but not on a budget. The longer you ride, the faster your top speed, the more time and money you need to spend on your build.
Click to expand...
What motor would you propose for something like that? What is the budget you are talking about?

Sent from my Mi MIX 2 using Tapatalk

 
Bigwheel said:
A 1000w motor will get you to 50km/hr but in order to be able to input 130-150w on the human end you will need to have a pretty high gear ratio available. I would say at the least a 50/11 depending on the wheel size.

However range wise at that rate of speed, even with your projected human input, you will be burning about 50wh's/km on level ground. Which as noted means a pretty pricey battery that will also add more weight to get to speed and keep there increasing wh/km consumption.

Maybe it's just me but based on my life long cyclist/motorcyclist experience I find that I am more comfortable going 200km/hr on a motorcycle than 50km/hr on my ebike for any length of time. I don't own a moto anymore but if I needed to meet your requirements that is the first option I'd consider.
Click to expand...
I am comfortable at 50 km/h on my bicycle. But I don't care if 40-45 is feasible. On ebikes.ca simulator it shows with specific systems I could do 42-43 km/h on 10 wh is that true? Is it too optimistic? What is your experience?


Sent from my Mi MIX 2 using Tapatalk

 
MadRhino said:
Your battery won’t be cheap, with the range and speed that you need.
Click to expand...
What is the most efficient hub motor at the market right now?

Sent from my Mi MIX 2 using Tapatalk

 
+1
For your requirements I would use the Leafmotor 1500w

Then, when you asked what motor I would choose for a fast ebike, it would be much bigger because for me, a fast bike does 70 mph and perfectly safe to ride that speed. I spend about 8000$ to build one, and that is using a lot of used components that I rebuild and mod myself. If I was going to build the kind of bikes that I use, all brand new parts it would be closer to 15000$.
 
MadRhino said:
+1
For your requirements I would use the Leafmotor 1500w

Then, when you asked what motor I would choose for a fast ebike, it would be much bigger because for me, a fast bike does 70 mph and perfectly safe to ride that speed. I spend about 8000$ to build one, and that is using a lot of used components that I rebuild and mod myself. If I was going to build the kind of bikes that I use, all brand new parts it would be closer to 15000$.
Click to expand...
Different meanings of fast [emoji23][emoji23][emoji23]
Ι want a touring bike([emoji605]). I have a race bike, thanks. I think 50 km on a straight, I am happy on e-bicycle.
I want something that burns less than 10 wh/km at a higher speed than what I do without the motor, eg 27 km/h. I would be happy at an avg speed of 40-50 kmh (25-30 mph)

Sent from my Mi MIX 2 using Tapatalk

 
Mike_S said:
On ebikes.ca simulator it shows with specific systems I could do 42-43 km/h on 10 wh is that true? Is it too optimistic? What is your experience?
Click to expand...

Example? The number I see there is more like 17 Wh/km, which if my math is right would mean a 33 Ah battery.

Oops, I forgot to credit you for the extra 50W pedal input, so say a 30 Ah battery. If you want to tour at 250W, which you mentioned as a possibility (27 kph), that would only take 27 Ah - but if you're going back to 50 kph, 40 Ah. Of course this is all rather theoretical, I think the label on the battery should probably read at least 20% more than what you might ever need.

My experience is a 12Ah 52V battery that's good for no more than about 50km, riding at pretty conservative speed, like 25kph.
 
donn said:
Mike_S said:
On ebikes.ca simulator it shows with specific systems I could do 42-43 km/h on 10 wh is that true? Is it too optimistic? What is your experience?
Click to expand...

Example? The number I see there is more like 17 Wh/km, which if my math is right would mean a 33 Ah battery.

Oops, I forgot to credit you for the extra 50W pedal input, so say a 30 Ah battery. If you want to tour at 250W, which you mentioned as a possibility (27 kph), that would only take 27 Ah - but if you're going back to 50 kph, 40 Ah. Of course this is all rather theoretical, I think the label on the battery should probably read at least 20% more than what you might ever need.

My experience is a 12Ah 52V battery that's good for no more than about 50km, riding at pretty conservative speed, like 25kph.
Click to expand...

Realistic. Yet not counting with the natural tendency to ease on pedaling when riders have a motor. :wink:
 
Yeah, pick two.

Here's what worked great for me. Not the only choice, but similar to the choice of two people who rode tours of many thousand miles.

Big hub motor, in my case an old crystalyte, capable of 3000w easy. I ran it on 52v, for a 30 mph ish top speed, what you are asking for more or less. What I did was run it on 2000w, 48v 40 amps controller. It was plenty of power to load up with a big fat load of batteries and camping gear, and still ride up rocky mountain passes, without slowing too much and overheating.

But to go 50 kph for 100k, about 60 miles, takes a battery so big you will be using a long cargo bike, or packing a trailer most likely. Or, as one of those long distance guys did, rapid charging every 40 k or so. There is nothing cheap about a battery capable of discharging 2400 watt hours. Because of typical loss of capacity as a batter gets used, you are looking at carrying three 48-52v 20 ah batteries to do the fast ride without charging. I rode much slower, packing about 40 ah, and could make 100 k easy, even up to 120. Going slow, my pedaling effort went farther.

If this is a camping trip, DO NOT underestimate how much wind your bike will drag, pulling a trailer, or covered in gigantic panniers.
 
50kph takes around 1100 watts for an ebike to maintain on flat ground with no headwind, give or take 100 watts. you plan to input ~150 watts, which is a massive human effort 100km, so lets round down to an even 1000 watts.

at 50km, you need 1000 watts output from the battery for 2 hours to go 100km

1000 x 2 = 2000 watts.

And watt hours is voltage times amp hours, or watts divided by voltage, so at your 52 volts:

2000 / 52 = 38.5

So you are going to need a 52 volt, 38.5 amp hour battery to make this bike work. But that will last a month, and then only go 99km. batteries degrade with each use. Its also super bad to run a lithium dry, so you need to run bigger than that. 20% over is a good minimum size increase, so:

38.5 x 1.2 = 46.2 amp hours

That means you need a 52 volt, 46 amp hour battery strapped to your bike to go 100km at 50kph with vigorous pedaling.



If you slow down to 40kph, those numbers get cut roughly in half.
 
Drunkskunk said:
50kph takes around 1100 watts for an ebike to maintain on flat ground with no headwind, give or take 100 watts. you plan to input ~150 watts, which is a massive human effort 100km, so lets round down to an even 1000 watts.

at 50km, you need 1000 watts output from the battery for 2 hours to go 100km

1000 x 2 = 2000 watts.

And watt hours is voltage times amp hours, or watts divided by voltage, so at your 52 volts:

2000 / 52 = 38.5

So you are going to need a 52 volt, 38.5 amp hour battery to make this bike work. But that will last a month, and then only go 99km. batteries degrade with each use. Its also super bad to run a lithium dry, so you need to run bigger than that. 20% over is a good minimum size increase, so:

38.5 x 1.2 = 46.2 amp hours

That means you need a 52 volt, 46 amp hour battery strapped to your bike to go 100km at 50kph with vigorous pedaling.



If you slow down to 40kph, those numbers get cut roughly in half.
Click to expand...
Thanks for the analysis Your last sentence is what I had concluded already. Going for 40 kmh avg speed. I don't want to make a truck out of my bicycle with a huge battery.

Is there a 10wh/km solution? That's what is maybe my new goal

Sent from my Mi MIX 2 using Tapatalk

 
Long range e bikes essentially are trucks. Even more so, if you are carrying or towing the camping gear.

But you can ride a long ride, a bit slower like you just concluded, on a fairly normaly loaded commuter. Start with a good frame bag, ( I really liked EM3ev's one) and pack it with at least 48v 20 ah or so of triangle shaped battery.

This gets you into a pretty decent ride, 30 miles or so at 18 mph. ( with still some reserve left) That's only 29 kph, but I never stopped being amazed how much farther I'd go at 18 mph, vs 20 mph. Really unbelievable. And of course, you still have a solid 20 miles there at fast speeds. (with no reserve) 30 mph or so. 48 kph. But slower of course, as you deplete the battery at the end of the ride.

Follow that up with additional 10 ah bricks, when you will be riding a truck. One in each pannier, low as it can be carried in the bottom. Maybe one more in a handle bar bag. But with 50 ah aboard, your range will be incredible. It will handle like shit too, and I betcha loaded like that you slow it down to 20 mph. You'd start to speed wobble at anything over that, on most "normal" bikes, loaded that heavy.

Eventually, you might build something specially made to carry batteries, and still ride a bit less truck like. This bike that eventually burned my garage down was designed to carry 48v 80 ah, and did it well, It rode really nice with the panniers empty, and just 40 ah in the frame trays. To maximize its range, it had a slow wind 500w motor, in 20 inch wheel. When given 1000w of 48v, its max speed was 18 mph, enforcing me to ride it at max efficiency speeds, where I could pedal up a big part of the total used. Typically 200-300 w used on the flat. Finished cargo mixte..jpg

Coming down a hill though, this frame was so stiff from side to side, it had just about zero speed wobble. The longer wheelbase helped too, but it was not as long as most long cargo bikes. I could still carry it on my swagman bike rack on the car.
 
Mike_S said:
Is there a 10wh/km solution? That's what is maybe my new goal
Click to expand...

Sure. The simulation says you get there when you drop down to about 36 kph - but that's assuming on one hand, you're pulling 150W on the pedals, and on the other that you're on an upright MTB platform. As MadRhino points out, this is about wind resistance, and that's a parameter that you can control to some extent. If you change the platform to "semi-recumbent", that same load goes up 46 kph. Around 40kph on level ground, the difference in load between upright MTB and semi-recumbent is more than 250W.

If you try that and it doesn't work for you, you don't get your money back. Mine is what I'd call semi-recumbent, but I don't ride that fast so I can't say for sure. I don't have any fairing at all, controls under the seat so my arms aren't streamlined, and I'm built kind of like a sail. With a Zzipper and a tail fairing, I might be eligible for the full recumbent category, which would bring it up to 53 kph at the same 10 Wh/km.
 
My bike approximates what you're looking for- Range of 110km at 40 kph on a level with pedaling. It has a total of 31.4Ah at 52V in the two batteries, 17Ah in the bag and 14 in the SuperShark. 30A controller in the bbshd mid-drive. Cost about $1600 total, with the original bike bought second-hand. Not exactly cheap, fast, and long range, but close enough on all three.

P1010003.JPG
 
Nicely done though, keeping all the weight in the middle. On a really long ride, I'm no so sure I'd like that top of the bar battery much, but I suppose it only bothers you when you actually stop. So better than on a commuter.

It would handle almost as well, if that second battery could be two small ones in a set of panniers though, and then all run in parallel on the ride.

Part of why my bikes had to be such trucks, was using heavier, larger format pouch batteries on most of my long range bikes. And,, where I was riding, if you broke down out there, you'd be looking at life or death if you were not carrying two full gallons of water.
 
Back in the day on rides of 100 to 165 km, ridden on road bikes or mountain bikes with road tires, the experience was: on the aero bars I could keep up, on the hoods or flat bars I was off the back. Long solo rides were always on the aero bars. They were modified to have higher and wider cups for comfort and folded up for riding the hoods or drops. Lots of cushioning on the cups was a good thing. I used higher placed cups because I was 45 kg overweight. The biggest problem was staying awake on long rides. Well, neck pain, burning boots and blazing saddle were other pain problems too. Oops, forgot numb hands.
Nothing wrong with drop road bars on an mtb or touring bike. Gravel bike drops are also an option.

If I were planning the riding you are, the bike would be full suspension, with low rolling resistance tires and using a triple road bike crank set, gearing would be something like 52 x 11. Toe clips or clipless would be important.

A rear direct drive hub motor should serve well. A torque sensing bottom bracket allows practical riding on the aero bars, no throttle to bother with. Not sure about rpm based PAS, perhaps a good combination could be found.

Like Dogman Dan mentioned, riding a little slower can add more range than would seem likely, my experience is the same.

Charging the battery to only 4 volts/cell and never discharging below about 3.5 volts per cell, for long battery life, should give battery cost of around 5 $US per 100 km over the life of the battery and would require more battery weight, bulk and up front cost than charging to 4.2 volts/cell and discharging to a lower voltage. But, battery cost per 100 km would be more, perhaps significantly so, when using a larger percentage of battery capacity on each ride.

I love what you are planning to ride. Keep us posted on what you do and how it works. The grand adventure continues ...
 
Thanks for the compliment, Dogman. I lurked here for 15 years and read all your posts before I built that bike. The top bar battery actually hides between my knees when I'm riding. When I ride on rail trails nobody hardly knows it's an ebike. If I'm going less than 40 miles I just snap it off and use the triangle battery alone. The bike has a very small frame (16") so the top bar is low. I keep the seat low enough that I can put a foot down without getting off the seat. With that much battery I'm pedaling for looks and exercise, not so much for power.
 
You must log in or register to reply here.
Back
Top