ENGY7000 – Energy Storage Tutorial
Question 1
One of the stated advantages of electric vehicles is the possibility of Vehicle to Load (VtL) discharging, whereby the electric vehicle battery is discharged to power a household or components of a household.
Consider the BYD Dolphin Essential which features a single 70kW/180Nm front-mounted electric motor, powered by a 44.9kWh Blade lithium iron phosphate (LFP) battery. It features a DC to AC converter to allow the EV to run appliances or devices.
If a household were to lose power due an extreme weather event, how long (or for how many cycles) could the Dolphin keep the following appliances running? I used
https://calculator.energyrating.gov.au/for the appliance data.
a) LG 315L Top Mount Frost Free Silver Fridge GT-3S
b) Westinghouse Washing Machine WWW9024M5SA
c) Bosch GV642B_WT Dishwasher
d) Daikin RZAV85C2V1/FCA85CVMA Split Cycle Air Conditioner to cool my home
What are some additional challenges of operating your EV as a home battery (outside of extreme weather events)?
Question 2
If a home battery has a discharge efficiency of 92% and a charging efficiency of 89% calculate the round trip efficiency for each cycle of the battery.
Question 3
Consider your night-time appliance use in your own home. Using the energy ratings calculator above, calculate the daily energy required for your house to operate from 6pm to 6am across the summer months. Then:
a) Estimate the size of battery required to keep your house ‘off-grid’ during the night.
b) Estimate the size of the solar array needed (18% efficiency) to charge the battery during the day. Use the moduleSIM.xls file and your home location as the input data.