OCTOBER 19-20, 2012 - YMCA University of Science & Technology

Proceedings of the National Conference on
Trends and Advances in Mechanical Engineering,
YMCA University of Science & Technology, Faridabad, Haryana, Oct 19-20, 2012
The energy equation for any section mentioned above can be given as:
(P m - P s ) t = D s (3)
D s = battery discharge
T = time
On substituting the values of velocity of the car, the amount of time in any particular section of battery discharge
can be obtained. Hence, on substituting the values of speeds from 25 to 60 kph on increments of 5 kph, the
corresponding time and hence the distance that could be travelled is obtained. The mechanical power required to
propel the car different velocities is listed in Table 1.
Table 1. Power consumption at different speeds
Sr. No. Velocity(kph) P a (Watts) P r (watts) P m (watts)
1 60 405.72 1631.28 2037.00
2 55 312.68 1497.32 1810.00
3 50 235.00 1361.00 1596.00
4 40 120.42 1088.58 1209.00
5 30 51.00 816.00 867.00
6 25 30.00 686.00 716.00
The corresponding mechanical power for the velocities from 60 to 25 kph is obtained. Using these values, the
time (using equation (3)) and hence the distance that could be travelled for two different sections are calculated.
The observations are as follows:
Table 2. Distance covered by the SEV at different battery charge percentage
Battery discharge
Battery discharge
Sr.
V(kph)
80%-50%
50%-20%
No.
Time(min) Distance(km) Time(min) Distance(km)
1 60 19.00 19.00 21.00 21.00
2 55 23.00 21.00 25.73 23.60
3 50 28.20 23.50 31.89 26.87
4 40 45.69 30.46 56.20 37.49
5 30 101.10 50.55 172.80 86.40
The efficiency of the battery is least(60%) while the battery discharges up to 80% of its capacity. Hence, for this
range the car is driven at its maximum speed, i.e. is 60 kph in order to cover maximum distance in least possible
time. For the battery capacity range of 80%-50%, maximum distance is covered at a speed of 30 kph, but the
time taken is much higher than that at 40 kph, as inferred from Table 2. While the time taken for discharge at 50
kph is lesser, there is a considerable loss of distance that can be covered. Hence, 40 kph is the optimum speed to
drive at in this range. Also, for the battery discharge of 50%-20%, where the efficiency of the battery is about
90%, the car is driven at 30 kph, thus covering maximum distance and allowing the battery to be operated at the
highest efficiency.
5.Chassis Design
Chassis is the main frame of the vehicle that provides strength and rigidity to the vehicle and houses the driver,
thus providing protection. Other components like batteries and electronic system are mounted to the chassis.
Table 3. Weight of the Components of the SEV
Component of the SEV
Weight(kg)
Chassis 50
Upper Body and Solar Panels 142
Lower Body 41
Batteries 82
Motor 15
MPPT 4
Wheels and other mechanical systems 40
Driver Weight 90
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