Why Does a Car Battery Get Hot?
2 Answers
The reasons for a car battery heating up are: 1. The efficiency of converting electrical energy into chemical energy is 50%, with most of the remaining 50% being released as heat. 2. The battery has internal resistance; the lower the charge, the greater the internal resistance. According to P=I*I*R, the power consumed by internal resistance is also converted into heat. 3. When the battery is fully charged, if charging continues, almost all the electrical energy is converted into heat rather than chemical energy. Notes: 1. If the battery becomes severely hot, consider that it might be self-discharging and generating heat. 2. This phenomenon indicates that there is a short circuit inside the battery's plates, reaching the end of its service life. Self-heating can lead to battery self-destruction, swelling, casing rupture, and electrolyte leakage. It should be promptly removed and replaced; there is no other solution.
Recently, my car battery got as hot as a baked sweet potato, which was really strange. Upon closer thought, the usual causes are either overcharging or a battery short circuit. I've experienced cases where the alternator voltage was too high, causing the battery to overcharge, increasing internal resistance and generating heat. There was also an instance of an internal short circuit where the separator was damaged, leading to overheating. Hot weather can exacerbate the issue, as car batteries tend to heat up more in summer. This is particularly dangerous because it can lead to fires or explosions, even melting surrounding wiring. I believe the first step is to turn off the engine and avoid attempting DIY repairs—safety first by having a professional technician inspect the charging system. For prevention, I regularly measure the battery voltage, maintain proper electrolyte levels, clean terminals to prevent corrosion, and conduct a check-up roughly every six months. Remember, a battery's typical lifespan is about three to five years—replace it promptly when it's past its prime to avoid major trouble.
