How long does it generally take to charge a car with a dead battery?

[VonJulia]

After a short period of parking that results in a dead battery, the car typically needs to be charged for one to two hours to restore normal functionality. If the car has been parked for an extended period, it may require an overnight charge to return to normal operation, or the battery might need to be replaced. Below is some relevant information about car batteries: 1. A car battery, also known as a storage battery, converts chemical energy into electrical energy. Most cars use lead-acid batteries, which are made from lead and lead oxide, with sulfuric acid solution as the electrolyte. The advantages of lead-acid batteries include stable voltage and low cost, but they require frequent maintenance and have a relatively short lifespan. 2. Based on lead-acid battery technology, maintenance-free batteries have been developed. These batteries have structural advantages and consume very little electrolyte, eliminating the need to add distilled water during use. Their lifespan is about twice that of standard lead-acid batteries, and they offer benefits such as high-temperature resistance and compact size.

[EthanRose]

Last time my car was completely dead, luckily I always keep a charger on hand. Generally, it takes about 10 to 12 hours to charge, mainly depending on the battery capacity and charger power. My car has a 60Ah battery, and with a regular charger, it takes a whole night to feel secure. If I need to use the car urgently, I can switch to fast charging mode, which can get it started in four or five hours, but doing this too often can cause the battery to swell. I’ve developed a habit now—in winter, if the car sits for more than three days, I disconnect the battery, and in summer, if it’s not driven for a week, I’ll hook up the charger for a two-hour top-up. Actually, a car battery is like a person eating—starving for too long and then overeating can harm it. It’s best to give it a slow charge for maintenance once a month.

[AxelRose]

There's really no fixed rule for charging a dead car battery. Among my friends, some can start their cars after just 8 hours of charging, while others need a full day. It mainly depends on the battery's health condition and the charger's current output. A standard household charger typically delivers about 5A, so a 55Ah battery requires at least 10 hours of charging. If the battery is over three years old, you might charge it for 12 hours and still fail to start the engine—in such cases, it's more practical to just replace the battery. My worst experience was ruining a battery by overcharging it because I didn't monitor the voltmeter. Now I've learned my lesson and use an automatic shut-off charger that stops when full, which is both convenient and safe.

[MacZoe]

A dead battery usually takes 6 to 10 hours to recharge. There are two main factors: the output current of the charger and the battery capacity. For a standard 40Ah car battery, using an 8A charger for about 6 hours should be enough to start the engine. Larger SUVs with 60Ah batteries might need up to 8 hours. Be careful not to use too high a current, as this can cause the battery to heat up quickly and damage the lead plates. I now check the battery terminals weekly for oxidation and disconnect the negative terminal if the car is parked for more than three days. Also, it's best to keep the hood open during charging for ventilation, since charging releases hydrogen gas.