FABRICATION OF SOLAR BICYCLE
Guide: Submitted By
Mr. Sunil Kumar Sumit Shahi
• Details of Component
a)DC Gear Motor
c)Sealed Lead Acid Battery(SMFB)
• Assembly of Component
• Connection of Components
• Problem aroused and their solutions
• Life of Set-Up
• Future Aspects
• The depleting reserves of fossil fuels made the engineers and scientists to look
for renewable energy sources. India is spending large amount of foreign exchange
to import crude oil even though we have abundant resource of solar energy. If we
utilize solar power for local conveyance, a large amount of currency can be saved
and we can also ensure pollution free environment and contribute to nation’s
• The general mode of transportation for local trip (with in a range of 5 km) is a
bicycle, motor cycle or electrical bicycle. Bicycles are the cheapest healthiest and
eco-friendly but poses problem in climbing slopes. Motor cycles are not affordable
to poor people and with the rising fuel prices and pollutions; it does not seem a
• Hence a bicycle which can be peddled as well as run on solar powered battery
seems to be suitable option to solve the issues.
• In human transportation as a personalized vehicle.
• For inter departmental transportation in huge campuses.
• In industries for different level personnel to move around to inspect the
• In hospitals, Airports, Shopping malls, IT campuses, Hotels &resorts, Power
stations, manufacturing units, etc.
• Light weight & easy to control, makes convenient for use by anyone.
• Controlled speed ensures rider’s safety.
• Can be used by old aged demography.
• On site charging facility. No need to visit fuel station.
• Firstly the DC Gear motor was connected to rear wheel through chain
drive, which is fitted on seatstay through nut and bolts on iron strips
welded to seatstay.
• The fabrication was carried out keeping in mind the maximum load the
motor will be able to withstand.
• Edge grinding was done to provide smoother surface finishing on
freewheel and iron strips.
• Welding to join the freewheel to DC motor shaft.
• All the fabricated parts were assembled.
• The throttle is powered by batteries which are fitted on the handle.
• The throttle gets powered through battery and sends signal/ output to the
DC Gear motor.
A. DC Gear Motor
• Geared DC motors can be defined as an extension of DC motor which already
had its Insight details. A geared DC Motor has a gear assembly attached to
the motor. The speed of motor is counted in terms of rotations of the shaft
per minute and is termed as RPM .The gear assembly helps in increasing the
torque and reducing the speed. Using the correct combination of gears in a
gear motor, its speed can be reduced to any desirable figure. This concept
where gears reduce the speed of the vehicle but increase its torque is known
as gear reduction.
• gear motor adds mechanical gears to alter the speed/torque of the motor for
an application. Usually such an addition is to reduce speed and increase
torque. A DC motor without gears is useful in many applications, for example
the simple fan. Contrast that with the motor that operates the turntable in
your microwave, a gearbox there reduces the speed so your food isn't thrown
against the interior wall.
Table 1: Specifications of Gear Motor
1. Length 160mm
2. Shaft Diameter 6mm
3. Voltage 24V
4. Weight 2.5 Kg
5. RPM 72 RPM
B. Solar Panels
• Light striking a silicon semiconductor causes electrons to flow, creating
electricity. Solar power generating systems take advantage of this property
to convert sunlight directly into electrical energy.Solar cells convert the
energy of sunlight directly into electricity through the use of the
photovoltaic effect. The photovoltaic effect involves the creation of a
voltage into an electro-magnetic radiation.
• There are two types of solar power generating systems: grid-connected
systems, which are connected to the commercial power infrastructure;
and stand-alone systems, which feed electricity to a facility for immediate
use, or to a battery for storage.
• Grid-connected systems are used for homes, public facilities such as
schools and hospitals, and commercial facilities such as offices and
• Stand-alone systems are used in a variety of applications, including
emergency power supply and remote power where traditional
infrastructure is unavailable.
Table 2: Specifications of Solar Panel
Fig : Solar panel
1 Maximum Power(Pmax) 20W
2 Voltage at Pmax 17V
3 O.C Voltage 12V
4 S.C Voltage 1.2A
5 NOCT 45
C. Sealed Maintenance Free Battery(SMFB)
• Sealed Maintenance Free Battery is a type of lead acid
rechargeable battery. They are widely used in large portable
electrical devices Batteries are used for storage of electrical
energy. Since the batteries are high in Capital cost it is necessary
that overall system be optimized to be economically attractive,
the storage Batteries with particular combination of properties:
Fast and Efficient Charging.
Very Little Wasted Energy.
Long Life, Improved Safety,High Reliability, High Efficiency.
• It demands for a battery with longer running hours. Among all
the existing rechargeable battery systems, the lead acid cell
technology is the most efficient and practical choice for the
desired application. Plastic casing is provided to house the
internal components of the battery.
Fig 5:Lead Acid Battery
1 Type of Battery SMFB
2 Size(lxbxh) 150x60x90
3 No of Batteries 2 batteries
connected in series
4 Voltage 12V (each)
5 Amp Hr 7.2 Ah(each)
• The maximum speed of a bicycle will be 10 km/h. It is required to vary the
speed depending upon the road conditions & traffic. Therefore an
accelerator or a throttle is necessary. Throttle allows us to drive the motor
from zero speed to full speed..
• The throttle is fitted on right side of the handle bar and is connected to
controller. The throttle converts DC voltage from battery to an alternating
voltage with variable amplitude and frequency that drives the hub motor
at different speeds.
• It consists of MOSFET transistors and a small microprocessor. This throttle
is technically referred to as a Hall Effect type.
• The throttle has three wires contains a black, red, and green. The supply
voltage is via red and black wires and is usually around 4 volts. Green wire
voltage increases as the throttle is turned.
Table 4: Specifications of a Bicycle
Drive Dual Powered ( Motor and Pedal)
Weight 30 Kg
Assembly of Components
• We installed the motor on the rear wheel of the bicycle by chain.
The bicycle rim diameter 0.52m. For connecting the motor to the
hub of wheel, we had to make some adjustments of motor to fit on
bicycle through chain.
• The batteries have to fit them in way that balancing doesn’t get
disturbed, so we decided to put them in the frame of the bicycle as
low as possible. We made a stand for carrying the batteries and for
providing side support we made side covers.
Problems Aroused And Solutions
MOTOR AXIS ALLIGNMENT
• The axis of motor’s freewheel and freewheel of rear wheel was difficult
to make on a straight line. For that we have fitted washers on rear wheel
axle before the joining of seat stay end to the axle so that there should
be minimum gap for rotation of chain. Also the motor is bolted to two
strips of flat plate of iron which is welded to seat stay such that the axis
of both the freewheel should lie in a straight line.
MATERIAL SELECTION FOR LINKS
• The material selection for the linkages for assembly of the battery was
very important as the weight of bicycle was a main concern for us.
Therefore, we selected Iron strips (width: 2cm, height: 0.6 cm) for the
linkages. Iron pipes were best suited for us because strength, weight and
cost were our concern.
• For determining the speed of our cycle we used a speedometer. We
took the reading in mps (meter per second) in no load condition,
which came out 2.77 mps, which is equal to 10km/hr.
• For determining the range of the cycle we have tested the cycle on the
college ground with the load of 110kg. The bicycle gave a test
performance for 2 hours with 2 fully charged batteries.
• The bicycle covered a distance of 30km with a speed of 10 km/hr.
• The batteries are of 12V, 7.2Ah and the current supply for charging
them is about thus the time required to charge a fully discharged
battery will be 4 hrs.
• The batteries are 2-3 years or 300 to 500 charge cycles maintenance
free whichever occurs first. One charge cycle is a period of use from
fully charged, to fully discharged, and fully recharged again
MAXIMUM CARRYING CAPACITY
• We assumed in the calculation that the weight of the cycle with the rider is110kg.
The total weight of the cycle is 30kg.
Weight of the cycle (without any assembly) = 20kg
Weight of the battery=2.5 kg
Weight of motor= 2.5 kg
Weight of all linkages= 5 kg
• Total weight of the cycle (20+5+2.5+2.5) kg= 30 kg
Maximum Speed : 10 km/hr
Range : 30 km
Charging Time : 4 hours
Battery Life : 2 years
Running Cost : Nil
Max. Carrying Capacity : 80 kg
• The only maintenance in the bicycle is of the batteries and the life of batteries is 2-3
years, they can be replaced with new ones.
The cost of batteries after 2 years = Rs 500
The cost of new batteries = Rs 1800
Thus the effective cost of new batteries will be Rs (1800-500) = Rs 1300
Thus the maintenance cost =Rs 1300/ (2x365) =Rs 1.7/day
S. No Item Description Amount(Rs.)
1 Solar panel 20 W 2500/-
2 Motor 24V 2000/-
3 Sealed lead acid batteries 2x12V, 7.2Ah each 1800/-
4 Cycle 3000/-
5 Manufacturing of Links 1000/-
6 Wires, Capacitor, Throttle 100/-
7 Soldering 100/-
8 Chain Drive 200/-
9 Transportation 2000/-
Life of Set-Up
• The majority of manufacturers offer the 25-year standard solar
panel warranty, which means that power output should not be less than
80% of rated power after 25 year.
• The rated power output of solar panels typically degrades at about
• The Maintenance of SMFB is after 3 years.
USE OF FLEXIBLE SOLAR PANEL
• The flexible e solar panels are also available in the market. Flexible
solar panels can be very suitable for the project as these can be used as
a solar coat for the driver.
SOLAR PANEL ON THE WHEEL RIM
• If the solar panel gets fitted onto the wheel rim then it will be helpful
for our project because of their ease in balancing and good looking
design. As shown in the figure the solar panel can be fitted onto the
rim without using extra space for the solar panels.
• More economical than fuel-powered cars and motorcycles, and cheaper
than buying an electrical vehicle for the city.
• No contamination, forget about CO2 emissions!
• The type of terrain or the distance, the electrical bike can be more
comfortable since it allows the rider to cover more distance or climb hills
when more moderate physical exercise is required.
• It’s going to be a cheap alternative for the commuter. Most
people, on their drive to work, go less than 40km. Its cleaner
and you never have to buy gas or change the oil. Thus leading
to a pollution free environment.
• This bicycle is cheaper, simpler in construction & can be
widely used for short distance travelling especially by school
children,college students, office goers, villagers, postmen etc.
It is very much suitable for young, aged, handicap people and
caters the need of economically poor class of society.
• The most important feature of this bicycle is that it does not
consume valuable fossil fuels thereby saving crores of foreign
• It is eco-friendly & pollution free, as it does not have any