This has happened twice in pass two days.

I live in Seattle, the temperature was about 94 - 95 in past two days. I drove CT back home with A/C on, I parked my car in garage with all windows and doors closed, then I drove to local store about 30 - 60 minutes later.
I saw the battery was almost full, but the battery fan sounded VERY VERY LOUD even at stop sign , I also felt the pulsation feeling when I push the gas pedal. ,(something like lost power intermediately) I stopped the car, and when to back seat to feel the battery vent temperature, it was very cool actually.
My wife told me to shut down the car, I restarted it about 30 seconds later, the MOST WIRED thing happened, the battery displayed almost empty (purple color) immediately, but battery fan became quiet then and the car ran normal afterward.

This happened twice already, I reported it to Lexus dealer, the technician had no idea what was wrong.

Does anyone experience it before?

 

i have not experienced what you described above, however, the weather in So Cal has been similar (high 80's - low 90's) and when i get in a hot car after a few hours of being parked in the sun, the battery cooling vent runs very hard and loud. even at a stop sign. that part is normal.

 

Hey there..reporting gets the idea to the dealership.schedule a time where they can take the car from you and inspect and have them try to duplicate the problem... my Nav unit was defective and self rebooted A LOT since i got it..they had to change out the whole nav unit and nav edu and now it works normal finally..it wasn't a known issue and unfortunately took a month after multiple times in and out with a loaner to get this resolved..a bit of hassle and disappointment..but oh well..thats what warranty is for and i love my star fire pearl fsport se