What is the reason for the charging failure of the Volvo S90 12V battery?
2 Answers
Internal failure of the battery control switch module. Below is relevant information about the battery: 1. Lifespan: Generally, a car battery has a normal lifespan of about two years; 2. Maintenance: If properly maintained, it can be extended, with the best lasting up to four years. Signs of a dead car battery: The car is difficult to start after being parked for two days, the car noticeably becomes sluggish when driving with the air conditioning on, etc. 3. Precautions for car batteries: Modern car batteries have a protection function that retains the minimum power required for ignition. If you turn the key without starting the engine and listen to music or turn on the lights, it can last for about an hour or so.
I've driven a Volvo S90 several times before, and that 12V battery charging issue really gave me a headache. The most common problem is a faulty alternator, where the output voltage can't keep up—either too high or too low—leading to unstable charging. Once the voltage regulator fails, the charging fluctuates significantly, which can damage the battery. Loose or corroded connections are another issue, especially when dust or rust builds up on the battery terminals, causing intermittent contact. A worn or slipping alternator belt can also reduce charging efficiency. Faulty control modules, like the charging management system, or software bugs may misjudge the battery's condition. Other factors include blown fuses, short circuits, or frequent short trips that prevent the battery from fully charging. I recommend using a multimeter to regularly check the voltage—normally around 14V. If it's too low, inspect the alternator; if too high, check the regulator. Don’t overlook regular cleaning of connection points and avoiding damp environments, as this can prevent many issues.
