What is the normal range for car battery leakage?
2 Answers
Car battery leakage typically ranges around 45 milliamperes. The causes of car battery leakage include: 1. Accidentally activating the anti-theft alarm; 2. Ground leakage from electronic components and circuits such as car electrical devices, wiring harnesses, sensors, controllers, and actuators; 3. Self-discharge and power loss due to short circuits or oxidation shedding of the battery plates; 4. Leaving electrical switches on when the car is parked. Solutions for car battery leakage include: 1. Checking whether the battery voltage and power generation are normal and whether the battery terminals are rusted; 2. Removing the negative terminal of the battery, setting the multimeter to the highest current range, connecting the red probe to the negative wire, and connecting the black probe to the battery terminal and securing it; 3. Turning off all electrical devices inside and outside the car, locking the doors, observing the current level, and adjusting to the appropriate range.
Having driven for so many years, the issue of car battery drain is something I need to address seriously. The normal range is generally between 30 to 50 milliamps, which is caused by electronic devices like the alarm system and clock still drawing power after the car is turned off. If your battery noticeably loses charge after just a few days of parking, the drain might be exceeding the limit. For example, my previous car had this issue—after sitting in the garage for a week, it struggled to start, and the measurement showed over 60 milliamps. It turned out to be a short circuit in the trunk light switch. A mechanic taught me a trick: regularly use a multimeter to test the negative terminal of the battery. If it exceeds 50 milliamps, check the wiring or modules. Developing a habit of doing a simple monthly check for leaks can save a lot of trouble, especially in winter when the issue tends to flare up more easily.
