The rental company staff did not check if the car key had battery power. On the second day, just when we were about to leave Melbourne, the car key died, and we couldn't start the car. Fortunately, we had relatives in Melbourne who happened to have a new car key battery. After waiting for 40 minutes and replacing the battery, we were able to head to our destination, the steam train, for which we had already bought tickets. We were worried we wouldn't make it on time, but thankfully, we didn't miss it. We immediately reported the situation to the car rental service, very worried that our relatives in Melbourne might not have a car key battery. If that had been the case, our day's schedule would have definitely been delayed. In the end, we never received an explanation or compensation for the new car key battery.