1. What is the capacity of the accumulator? *

2. In order to increase the capacity of our accumulator, eachseries cell has 3 additional cells wired in parallel to it; thisresults in our accumulator containing 576 cells wired in a 144S4Pconfiguration.Each cell has a capacity of 2.5Ah.

3. How much energy (kilowatt.hours) does our accumulator have? * At competition, the energy usage of our electric vehicle ismeasured to calculate its efficiency over a 22km race.

4. Provide at least 3 reasons why you think we made thisdecision. * In 2015 and 2016, we used LiPo Pouch cells yet in 2017& 2018 we made the decision to use Li-Ion 18650 cells.

Question 2 All electric vehicles have a motor controller, thisis essentially an inverter which turns the DC input into a PWMoutput. The motorcontroller we use is the UnitekBAMOCAR-D3-700-400.The bus circuit capacitor of a motor controllerhas a high capacitance; if this capacitor is not pre-charged beforebeing energised with the full accumulator voltage it willcatastrophically explode.

a) Why will the capacitor explode? * HINT: what cannot changeinstantaneously across a capacitor?

b)List the rules regarding the pre-charge circuit. *

c)Using this rule, what value of resistance will charge thecapacitor to at least 540V after 5 seconds? Assume accumulatorvoltage is 600V. * HINT: you will need to find out the value of thecapacitor within the motor controller, consult the manual.

d)What voltage must the motor controller be discharged to within5 seconds of de-energising? *