Battery Dead problems of the 2015 Nissan Leaf

When the 12-volt battery failed on my 2015 Nissan Leaf, the car would still turn on and would move forward without pushing on the accelerator. The brakes did not work either. This happened to me both in a grocery store parking lot at night and then the next morning on a residential street. Similarly, when it turned the car on in my driveway, I put it in reverse, and the car moved without me pushing on the accelerator and the brakes did not engage when I pushed on them. The car behaved this way 4 times, including once for the Nissan dealership service worker who had to pull the car forward in the line of cars waiting to be serviced. After Nissan replaced the 12-volt battery, the problem disappeared. Several Leaf owners have told me to report the problem, because it is a safety concern that the car can move but the brakes do not work when the 12-volt is failing. I called Nissan to notify them of this problem but did not get a response beyond a call from consumer repairs saying she would make a note of it.