Knowing battery voltage is good but is not the main indication of battery condition. As car battery has 6 plates, each plate will hold at least 2V and a total of at least 12V or higher to be in working condition. Most common battery voltage readings should be around 12.4V to 13V (at most). If you have a battery that reads less than 12V for example at 11V, meaning is one of the plates is not right.
The main battery condition indicator is the battery cold-cranking amperes (CCA) and the battery resistance – mini ohms (mΩ - the lower the resistance, the longer the lifespan). For Nissan Latio with 1.5l engine, the minimum to crank your starter motor is at least 150 CCA or not more than 16mΩ. The problem with getting a new battery in the battery shop, does anyone get the battery man or mechanic to show you your new battery’s CCA and resistance to make sure that you are getting a fresh, brand new and powerful battery? How do you tell that the battery you are getting was not left on the shelf for a few months? Of course, the battery shop where you got your new battery must have this expensive battery meter in the 1st place to show you the readings and condition. Showing you battery voltage reading does not really tell you the battery actual condition as long as the reading shows more than 12V. You can charge up any good condition battery (not necessary new battery) to have higher voltage to show.
Not sure why there are so many guys getting more than 13V reading even after a few hours without engine running. Is your voltage meter a plug-in type or direct connection to battery or ignition? Normally, most plug-in volt meters in the market read either 0.3V to 0.5V higher (or some volt meters read 0.3V to 0.5V lower) than actual battery reading... The most accurate voltage reading will be direct connection to battery if possible or at least to ignition but of course, in the 1st place, your volt meter must be accurate as well.