What Causes a Car Battery to Overheat?
2 Answers
The reasons for a car battery overheating are: 1. Battery aging; 2. Increased internal resistance; 3. Drying up of the electrolyte; 4. Internal short circuit. Solutions for an overheating car battery include: 1. Adding water; 2. Using desulfation and depolarization techniques; 3. Replacing with a new battery. Battery maintenance methods are: 1. Wipe off the accumulated white acid corrosion powder on the battery terminals to extend service life; 2. Add distilled water to the level between the upper and lower marks; 3. Check if the battery is charging properly. The functions of a car battery are: 1. To power the starting system, ignition system, and electronic fuel injection system during engine startup; 2. To supply power to the vehicle's electrical equipment when the engine is off or at low idle; 3. To act as a voltage stabilizer for the vehicle's entire electrical system; 4. To store excess electrical energy generated by the alternator.
I recently encountered the issue of a hot car battery, which felt quite troublesome. The cause is most likely an overcharging alternator, meaning the voltage regulator is faulty and continuously pumping excessive electricity into the battery, causing internal overheating. Another possibility is an internal short circuit in the battery, such as direct contact between the plates, leading to excessive current and heat generation. A common factor is also battery aging—over time, internal resistance increases, naturally causing heat when current passes through. I’ve also experienced cases where parking under high summer temperatures with the AC or headlights running creates excessive load, making the battery heat up. This poses significant safety hazards—overheating can lead to electrolyte leakage, fires, or even explosions. So, if you notice this, stop the car immediately, turn off the engine, and let it cool. Don’t attempt DIY checks; take it straight to a repair shop to test charging voltage and wiring. For regular maintenance, check battery terminals for corrosion or looseness every six months. Car batteries typically last three to five years—saving money here isn’t worth the safety risk.
