How long can a car battery generally last when not in use?
2 Answers
Generally, a car battery can last for about two months when not in use. Even when the car battery is not connected to any electrical components and has no load, it will lose about 1% of its charge daily due to the self-discharge rate of the battery. A dead battery will affect the car's ability to start and the use of onboard equipment. Maintenance and care for car batteries: 1. If a battery is left unused for a long time, it will gradually discharge on its own until it becomes unusable. Therefore, the car should be started periodically to recharge the battery. 2. When the ammeter shows insufficient charge, the battery should be charged promptly. 3. The density of the electrolyte should be adjusted according to standards based on different regions and seasons. During daily driving, regularly check whether the small holes on the battery cover are ventilated. If these holes are blocked, the hydrogen and oxygen produced cannot escape, and when the electrolyte expands, it can rupture the battery casing, affecting the battery's lifespan.
I've learned my lesson several times with car batteries left unused. Generally, a new battery can last two to three months, but an old one might start losing charge in about a month. Last winter, I left my car in the garage for two months, and when I tried to start it, the battery was completely dead—I had to get a jump start. This happens because the battery discharges slowly on its own. Lead-acid batteries, the most common type, lose a few percent of their charge each month. In hot weather, like summer, the discharge is faster, maybe lasting only three to four weeks; cold weather is slightly better. If the car has an alarm system or something similar, it drains the battery even more. So, I recommend not leaving it idle for more than a month. It's best to start the engine every two weeks to charge it for a while, or use a battery maintainer, which automatically charges and prevents damage.
