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Solar electric bicycle!

The bike that you never get bored…

We will see how easily I converted a normal bike so it would move both as a regular bicycle, and motor assisted too!

My goal from the beginning was not to remove the characteristics of a normal bicycle:

The cyclist must pedal, otherwise ...go to buy a motorcycle! The electric bicycle will be able to assist the cyclist making longer journeys.

The second objective was to make the electric bike light and beautiful. I think I got this too!

The conversion to electric was very easy: I bought a ready conversion kit which includes everything you need:

1. The front wheel which in the centre has a 250W built-in motor that drives the wheel with electricity.
2. The controller which controls the speed of the motor etc. I placed him in a small bag under the seat.
3. The handles on the steering wheel (the right one functions like the "accelerator" in motorbikes to regulate the speed).
4. The brake handles that replaces the ones that are already on the bike: When you push the brake, the motor stops.

As shown in the photographs, to the conversion is easy:

1. Unscrew the front wheel and replace it with the new wheel that has the built-in motor.
2. Unscrew the brake handles and replace with the new ones.
3. Find a convenient spot to place the small size controller.
4. We connect all the cables (the motor, the brakes and the throttle) to the controller according to their colour. Finally, we connect the two wires of the controller, positive and negative (red and black, respectively), over their respective poles of the batteries which I placed in a small box behind the bicycle rack.

The batteries are 3 X 13AH sealed lead acid, 12V. They can be recharged with the charger from an electrical socket as well as with solar energy from solar panels.

They can ensure autonomy for approximately 40 kilometres in normal ways with a few inclines and with the cyclist to help a bit with the pedal, especially in the start (since there is greater power consumption).

I could use smaller and lighter batteries (e.g. 7AH) with half the size and weight.

 

Cycling with the electric bicycle

The feeling is amazing! While continuing to cycle, you are not getting tired, there is no sweat and you feel clean and refreshed no matter how many Km you have cycled.

It is not a motobike, it remains a bicycle. Just where you used to cycle 5 km before now you do 15 without problem, so you are working out more. It's like you have an invisible professional racing cyclist who is pedalling with you! In the hills especially this is very important.

Moreover, you feel more active. It accelerates much faster after stops; it develops higher speeds on the road (up to 32 kilometres per hour with light pedal) so you can adjust to the requirements of traffic. Everybody is looking at you amazed!

Finally, you have a tool if necessary, to move somewhere where there is no other way (e.g. inaccessible roads, lack of fuel, etc.).

The technical characteristics and the cost to convert to an electric bicycle

The motor is 36V - 250W and needs no maintenance (it has permanent magnets). The 250W is the average power that a professional cyclist produces during a race.

The batteries are 3X12V connected in series in order to give the 36V that the motor needs. The capacity should be at least 7AH so we could have autonomy of about 15-20 km a day.

I put 13AH, but they have more weight and volume. If you put 7AH, the bike’s extra weight is about 12 Kg, so you do not feel it as you move. If it was the most expensive NIMH batteries, the weight would be around just 5 Kg. Under normal use they would last probably around 2 years.

The final cost, when I made it (2008), was around 350 Euros for the conversion kit. The batteries cost about 15 Euros (7 AH) to 30 Euros (13AH) each.

Charging with solar energy

I have connected 3 small solar panels of 20 Watt/p in series and I am allowing it to charge every morning.

I can also remove the box with the batteries and take it with me to charge, in the house from a plug.

To fully recharge the batteries of 7AH, 2.5 -3 hours are sufficient with a charger or in the morning (5-6 hours) in the sun. This will happen only if they were completely empty. If our ride was for example only 7-8 kilometres, then it is going to take half the time to fully recharge again.