500kWh/month seems like a lot.
But in saying that I would have used 120 kWh in a 2.5 day period. So if I regularly travel to Auckland or even Hamilton; maybe needing to visit a sick parent or similar. I could easily get to 500kWh in a month.
I know someone who, until they died, used to travel to Hamilton from Taupō at least twice a week to see their sick dad. This went on for around two years. At around 300km per round trip, that is 6-900km/week. Say average is 700km/wk or 2800km/month. A good EV will get 17kWh/100km on the open road; 20kWh/100km for a mid range EV. So we are talking 474-560kWh/motnh.
You better hope that at least 1/2 of your charging is at home over night.