Intermittent no power-Help

Greetings Leaf owners,

I'm new to the Leaf world and I generally love it. However a problem has arisen.

I have a 2015 Leaf SL with 95,000 on the clock and 10 bars of battery. The car is beautiful and normally runs perfectly.

Yesterday, I was at work and the car got me to work and to lunch and back to work as it normally does. When I went to go home for the day, the Leaf had no power at all. No key fob, no lights on the dash, anything. I thought it might be the 12 volt so I went back to my work that night and tried to jump it. Didn't work, still the same no power issues,

The next day, this morning, I drove in with my other car and parked next to the Leaf. I hit the key fob and the power was back. I started it and drove it around a bit and it was perfectly normal again. No issues. No dashboard warnings. I live close to work so I rode my bicycle
to get the Leaf and it started and I drove it home and it was just fine and normal. In my driveway, when I shut it off, this happened. The normal shutdown chime didn't happen and everything went dark, including the power button. Also, there was an audible long and continuous beep sound, about 30 seconds. Then the power came back on again. I pushed the power button and it came to life like normal. When I shut it off this time, it did the same thing, no lights, and this time the chime went for a couple of minutes. It also seems like I was hearing something like relays clicking under the hood during this time. Also the brake pedal feels different when it's in this no power state.
I do have an EV certified Nissan dealer near me in the Detroit area but I'd like to have a little knowledge before I take to the dealer.

Any opinions or advice would be welcome.
Rob

I will give you the standard response of a weak/failing 12V battery as a possibility. Also, a more likely issue (since it is intermittent) is a loose or corroded ground connection of the negative cable of the 12V battery. There is a ground connection to the body (fender) near the 12V battery that looks like a cable support clip but is really a ground connection. Check/clean that connection carefully as well as checking/cleaning all other 12V battery and cable connections.

Thanks for the suggestion. As it turned out, when I removed and reinstalled the 12 volt battery for testing, I discovered that the bolt that connected the wire harness to the positive terminal clamp was extremely loose and not making consistent contact. The battery tested normal, and after tightening the bolt, the car was a good as it ever was.

Thanks Again
Rob