Wednesday, November 23, 2011

Thibaut Salloignon zelf aan het woord.

Here is a draft about my bike:
I'm working with Johan on the Kit project for the Velomobile Seminar in september 2012 and he asked me to talk about my project, that is to say, a Alleweder with a direct drive rear motor hub.

Before I talk more about my velomobile I will explain my thinking behind this bike.

I'm french and I live in a hilly region, but I love biking and my goal is to able to live in a hilly countryside without dirty car.
Few years ago I heard about velomobile and I though it was the solution for me, but after a short thinking, I found two major problems, it would be difficult to go up hill and dangerous to go down hill so actually it would be worth than my road bike.
I could use a standard electric assist with freewheel but it would only solve the first problem.
Then came the idea to use a powerful (1200W) direct drive motor on the rear wheel, here are the advantages:
  • I can go up hill at 25 without overheating the motor (it's the main issue for hub motor, if the motor is not strong enough, the efficiency drop)
  • I can use the wheel as an electric brake and there is two option to active the regeneration, the first one is to go faster than the natural motor speed, it depend of the voltage and the number of coil,in my case, 48V and 10*8 motor, so I end up with a speed of 42km:h, the maximum speed I can do with my bike is 50km:h. The other solution is to pull a little bit the brake to switch a sensor that activate the e-brake, but I have only one braking power setting.
  • I can go backward, so I can close the hole for the feet and do a lot of useful think.

Ok that's for the direct advantages, then come the indirect one:
  • I'm almost never use my mechanical brake, and I can use small drum brake.
  • I need only a 7 speed derailleur on the rear wheel, it makes the shifting very simple, I can always start with the high gear.
  • I have a  good battery for my light, usb plug,... that will never run out of energy.
So with all this idea, I decided to buy a Alleweder kit (without the rear wheel, derailleur and light) and a Hub motor from 9Continent with a 48v battery of 15ah capacity of Lifepo4 and a 30A controller with a Cycle Analyst to be able to test different settings (with the help of Declic-Eco who rebuild the "made in china" part)

I end up with a 4300 euros, 50Kg  velomobile that can do an average speed of 35km:h with a range of 120km. I should "theoretically" be able to make 200 000 km with the same battery. I can ride safely in the hill.
The best think about this velomobile, it's that I can always pedal at the same power all the time and that's very good for my body. Instead of pushing hard uphill and braking downhill, I'm doing a constant effort, even in the corner, I keep pedaling as I'm braking. There is quite a lot of energy loss when you brake or you stop pedaling, downhill or in a corner. If you think about body efficiency, when I'm riding my velomobile, I'm close to a Fitness exercise.

I would love to live in a country not so hilly, and not using an electric assist, but at the end, that's the best solution I found for me (I know that's not the best for every one).
My electric motor work like a gearing system and a brake at the same time. I have improve my pedaling Technic these last months, now it get back 50% of the energy I use with an average speed of 35km:h. It's possible to improve this.


Het project van Paul Lavelle en zijn eigen ervaring met de elektrische ondersteuning overlappen elkaar. Thibaut kan op dit moment niet verder ingaan op de mogelijkheid om het rendement van zijn systeem in de buurt van de 85% te krijgen. Als de fiets van Paul Lavelle in productie is wordt hier uitvoerig verslag van gedaan. Wordt vervolgd


  1. Johan,
    Electrical power assist is a nice hobby for us also. I would like to share experiences with Thibaut. Can you pass my e-mail to Thibaut? Thanks!

  2. My old Flevobike Alleweder also is equipped with an electric assistance. In my case I chose a Cyclone engine that is installed at the very front of the bike. Interesting to read about different solutions for different situations, although all around velomobiles.

  3. An efficiency of 85% for a cycle is a very high figure I think. Lets assume the efficiency of the motor is 0.95 and the efficiency of a charge/discharge cycle is 0.90. Than the total efficiency will be: 0.95*0.95*0.9=0.81 (81%). At braking and starting the motor torque is typically high and the motor current too. Not so good for efficiency. I think 0.9*0.9*0.8=0.65 is about how good it will get. But I would be very interested to learn more about your findings

  4. Actually my goal is 100%, I'm talking about the energy that go back to the battery, I don't say that the efficiency of the system is 100%. Let me explain how it works. Let's say that the total efficiency of the system is 50% and that would be very good(battery-->electronic-->motor-->road-->Generator-->electronic-->battery). So now if I use only the motor and a go up and down at the same speed, I will get back 50%. But if I go up only with humain power and then go down and I generate electricity, I produce more than I use(like a dynamo on a bike, but you don't want that). So if you want 100%, you have to pedal uphill of course, but also downhill and brake a little bit, when you brake, in corners,...So your average speed depend of you own power (if you are not very powerful, you will have to limit more your speed downhill).But at the end you will still go faster than a normal bike...why?
    Because if you go uphill at 25 instead of 5, you need only 5 times more energy (because the gravity force is the main resistance and it's linear)to go 5 time faster. Compare to going downhill at 60 instead of 40 where you need 3 times more energy to go only 1.6 time faster (because the wind resistance is the main resistance, and it's not linear).
    To sum up, it's better to use energy to fight the gravity than to fight the wind, even if the efficiency of the system is not 80%. And also, for you body it's much better to do a constant effort, the efficiency of you body will be better ;)