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

[OTalia]

If the car battery is in a state of insufficient charge, driving the car at a constant speed above 2000 RPM for approximately 30 minutes can fully charge it. 1. Car charging principle: There is a generator next to the car engine, which is driven by the engine's belt to rotate and generate electricity, supplying power to other parts of the vehicle. At the same time, the generator charges the battery, ensuring a continuous source of electrical energy. When the car is idling, the generator's voltage (i.e., potential difference) can meet the charging conditions. Although the current is low, it is generally sufficient, provided that high-power devices such as the air conditioner, high beams, car audio, or refrigerator are not used. Otherwise, the generator's maximum output power may be exceeded, leading to battery depletion and permanent damage. 2. Severely depleted batteries require a charger: For batteries that are severely depleted, using a dedicated charger is the correct approach. Relying on the car's generator for charging takes a significant amount of time and is not very effective. During routine maintenance, it's also important to monitor the battery's condition. After parking, all electrical devices in the car should be turned off to avoid prolonged inactivity, which could lead to battery depletion. This might prevent the car from starting normally the next time it is used.

[KiraAnn]

I think this is a good question now because it touches on a common doubt encountered in daily driving. Whether a car can be fully charged while driving depends on the type of vehicle. For conventional gasoline cars, the alternator charges the 12-volt battery while the engine is running, usually taking anywhere from several dozen minutes to an hour to replenish it fully—no need for intentionally prolonged driving. As for hybrid vehicles, like those from Toyota, the engine also charges the traction battery while operating, with the charging time depending on driving conditions. For instance, highway cruising might allow significant charging in 30 minutes to an hour, whereas stop-and-go city driving is far less efficient. Pure electric vehicles, on the other hand, can only recover energy through regenerative braking while driving and won’t actually reach a full charge—plugging in while parked is necessary for that. Many factors affect charging speed, including driving speed, air conditioning usage, and battery aging. From experience, I’d suggest not obsessing over incomplete charging while driving; just drive normally, as maintaining battery health is ultimately more important.

[DelEli]

I remember driving a plug-in hybrid a few years ago, and charging really depends on the situation. Generally speaking, relying solely on the engine to charge while driving, I estimate it takes at least an hour of continuous driving to see a significant recharge, especially noticeable on long trips. But for those of us who mostly drive around the city, like commuting for half an hour, you might only gain a bar or two of charge, far from a full charge. It's important to note that different models vary greatly; cars with smaller engine power charge more slowly. Additionally, driving habits are crucial—sudden acceleration and hard braking waste energy recovery opportunities. Using cruise control or going downhill is more efficient. I usually make sure to check the battery health before long trips and avoid driving with an empty battery since repeated deep discharges can damage it. Overall, don't expect driving to fully charge the battery instantly, but it does help save some money on gas.

[StJanelle]

Whether driving can fully charge the battery depends on the car type. I observed that pure electric vehicles mainly rely on regenerative braking to recover energy while driving, but this can only charge up to about 80% at most. To fully charge, you need to park and plug in. Hybrid vehicles like the Prius charge the battery when the engine is running, typically replenishing a significant amount of charge after driving for about 40 minutes to an hour, but it's difficult to reach a full charge due to system design limitations. Factors affecting this include speed—charging is faster at higher speeds. Also, pay attention to environmental temperature, as charging efficiency drops in cold weather. Simply put, don’t rely on driving as the main charging method. For daily use, it’s not a big issue as long as the battery stays within a reasonable range.

[JasonLynn]

I think charging time is affected by multiple factors. Driving conditions are the most critical - maintaining a steady speed on highways allows for efficient charging, potentially boosting battery level significantly in just half an hour. Conversely, frequent stop-and-go traffic in urban areas yields minimal energy recovery, making charging nearly ineffective. Vehicle type also matters, with hybrid vehicles charging faster than the small batteries in conventional fuel-powered cars. Battery condition shouldn't be overlooked either, as aged batteries might deplete in under an hour. Weather extremes like high or low temperatures can also slow charging speeds. My advice is to maximize energy recovery through coasting and downhill driving during daily commutes, while ensuring regular battery health checks. Remember, in-motion charging is a gradual process - don't expect instant full charges.