Hello Scotty ,
I have a Toyota Corolla 2010 model Diesel 1.8L D-4D 95000KM done..But 4 days before I tested the battery voltage when car is idling without A/C on it is showing about 16.58Volts , but battery manufacturer recommendation is only 14.4Volts max..What is the problem?? Will it cause any problems to electronics inside the car??The battery electrolyte is also depleting rapidly...

it's overcharging, generally a bad alternator