A battery electric vehicle is tested on a simple drive cycle at a constant velocity of 10 m/s for a duration of 5 minutes and at a constant speed of 15 m/s for another 5 minutes. 

The vehicle road load power is described as follow: 

P_R=180v+3.6v²+0.3v³

and the efficiencies are as follow: 

• Battery to wheel efficiency (
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  \eta _B-W) is 85% 
• Grid efficiency ( \eta Grid) is 34%
• Charging efficiency from the plug to battery ( \eta C) is 86% 

a. Determine the total energy consumption of the vehicle (From grid to wheel) 

b. Determine the vehicle fuel economy in Wh/km (From battery to wheel)