Can a car battery be charged at idle speed?

2 Answers
ODawson
07/28/25 4:21pm
It is possible to charge a car battery at idle speed. The details are as follows: Idling refers to a working condition where the engine runs without load, the gear is in neutral, consuming fuel while the vehicle remains stationary. As long as the engine is running, it drives the alternator to work simultaneously. For household cars at idle speed, the alternator provides a voltage of 14V and a current of around 40A. Therefore, a car can indeed charge its battery while idling. At idle speed, although the RPM is low, it still drives the magneto to work, thus outputting a stable DC voltage. Since the battery's power capacity is not that large, the charging speed will be slightly slower. Modern cars use AC generation, and the battery's power is mainly used to start the car, which consumes a significant amount. However, once the engine is running, the battery's power is no longer consumed.
Was this review help?
19
3
Share
Gregory
08/11/25 11:16pm
As a car enthusiast, I know that when the engine is idling, the alternator can still function, but the charging efficiency is much lower compared to when driving. At low engine speeds, the power generation is minimal, and charging a depleted battery might take one or two hours, progressing very slowly—especially in cold winter temperatures. In the past, when my car battery was aging, I tried idling overnight to barely get it started, but it was far less effective than driving for a few minutes. Additionally, idling wastes a lot of fuel, leads to severe engine carbon buildup, and increases maintenance costs. Battery lifespan may also suffer due to slow or overcharging. While technically possible, it's not ideal; I recommend using it briefly in emergencies. For long-term battery depletion, driving to charge or replacing the battery is better. By the way, check the voltmeter—during idling, it usually reads around 13 volts, enough to maintain but not fully charge the battery.
Was this review help?
14
1
Share
Expand All
More Forum Discussions

What is the Difference Between L and T in Cars?

The differences between L and T in cars are as follows: 1. Different engines: T is the abbreviation for turbo, meaning turbocharged engine; L is the unit for displacement in liters, referring to a naturally aspirated engine. 2. Different fuel requirements: T-displacement engines require a turbo for boosting, needing more fuel for the boost; L-displacement engines do not require additional fuel for boosting. 3. Different failure rates: T-displacement cars, due to the turbocharging in turbocharged engines, can lead to more severe engine wear; L-displacement engines do not require turbocharging, resulting in less severe wear.
10
2
Share

How to Use the Tire Pressure Monitoring System in Hyundai Elantra?

Hyundai Elantra's tire pressure monitoring method: The tire pressure monitoring in Elantra is enabled by default. If not activated, press the tire pressure monitoring button, and an icon will display briefly. It will only alert when any tire pressure is low later. After the tire pressure warning light illuminates in Hyundai Elantra, there is no manual reset button. Driving the car for a certain distance will automatically turn off the light. The Elantra is a car model launched by Beijing Hyundai. In terms of body dimensions, its length, width, and height are 4542mm, 1775mm, and 1490mm respectively, with a wheelbase of 2650mm.
6
2
Share

Does the Nissan Teana need to have its timing belt replaced?

Nissan Teana does not use a timing belt; it is equipped with a timing chain, which requires inspection every 100,000 kilometers and replacement if damaged. The main function of the engine timing belt is to drive the engine's valve train, ensuring that the intake and exhaust valves open and close at the appropriate times to allow the engine cylinders to intake and exhaust air normally. The Teana is a flagship mid-to-high-end luxury sedan under the NISSAN brand, perfectly combining precise driving dynamics with absolute comfort engineering, elevating the design concept of mid-size sedans to a new level. In terms of body dimensions, the Teana measures 4868mm in length, 1830mm in width, and 1490mm in height.
19
4
Share

What is the chassis analysis of the Enclave Plus?

Enclave Plus chassis analysis is as follows: Engine guard plate: The original vehicle is equipped with a fiberglass engine guard plate; Opening the engine guard plate reveals a lateral stabilizer bar, which enhances the vehicle's stability during cornering. Lateral stabilizer bar: Above the lateral stabilizer bar is the oil pan, unlike the aluminum oil pan of the old Enclave model, the Enclave Plus uses a bakelite material, which offers better heat dissipation and strength. Aluminum components: The front triangular arm, steering knuckle, and other parts are made of aluminum, providing better strength compared to cast iron, reflecting Buick's commitment to using genuine materials.
14
1
Share

How to Manually Polish a DIY Paint Job?

Adjust the speed of the polisher and fully moisten the sponge wheel with water, then shake off excess moisture. First, apply a small amount of C3 polishing compound to the paint surface, starting with the roof. Keep the polisher's sponge wheel tangential to the paint surface with moderate pressure and consistent speed. Polish in a specific sequence, avoiding random movements. After using C3, switch to a gloss enhancer and repeat the above steps.
15
3
Share

Can you get a motorcycle license at 16?

No. You must be 18 years old to obtain a motorcycle license. When applying for a motorcycle license, you need to prepare relevant materials, which generally include your ID card and eight one-inch white background photos, as well as the physical examination fee. Due to regional differences, the cost of applying for a motorcycle license may vary. Here is some related information about motorcycles: 1. Characteristics of motorcycles: Motorcycles are two or three-wheeled vehicles driven by a gasoline engine, with handlebars to steer the front wheel. They are lightweight, flexible, and fast, widely used for patrols, passenger and cargo transportation, and also as sports equipment. 2. Types of motorcycles: Broadly speaking, motorcycles are divided into street bikes, road racing motorcycles, off-road motorcycles, cruisers, touring bikes, etc.
1
2
Share
Cookie
Cookie Settings
© 2025 Servanan International Pte. Ltd.