Battery went dead after work third time in 3 months dealer cant find anything wrong!2011 rx 350 with 30,000 miles.Time for a new battery!

 

Yes, your battery most likely have a bad cell that prevents it from holding a charge.

Note: When you buy a new battery, i would also buy a charger also to fully charge the battery at least once a month to help the new battery last longer.

Most car batteries never get a full charge from the alternator alone due the drain of the car's electronics and short drives, so the batteries end up dying sooner than the could should last if they were fully charged more often.

Just my advice to get the most life from your batteries.