How long does it take to charge at idle speed?

[SanNolan]

Charging at idle speed takes about 1 hour. If the car is not driven frequently and you are worried about battery drain, it is recommended to start the car and let it idle for about 20 minutes every week. If the car is used regularly, the battery will be charged while consuming power, so there is no need to worry about the battery level being too low. If the car has not been driven for a long time, it may lead to battery drain or even damage. It is recommended to remove the car battery or disconnect the negative terminal of the battery when the car is not in use for an extended period. This way, the battery will not consume power when the car is not started.

[LeChase]

I guess you want to know how long it takes to charge the battery while idling in place, and it really depends on the specific situation. Last time my battery was drained, after sitting for a few days, I had to idle for 35 minutes to barely get enough power; if it's just a slight discharge like forgetting to turn off the headlights, maybe 15-20 minutes would do. Factors include battery age—new ones charge faster, while old or problematic ones might take over an hour; temperature is also crucial—charging is half as slow in cold winters and faster in hot summers. Additionally, the engine idle speed is usually around 800 RPM, and the alternator output isn’t high, providing only about 10-20 amps of current, far less than the 40-60 amps when driving. Overall, this method is inefficient and not eco-friendly—prolonged idling wastes fuel and may cause engine wear. I suggest not sticking to this method; simply driving the car for 10 minutes at high speed is more effective, or using a portable charger. Regular checks on the battery and charging system can prevent similar issues.

[LeJoseph]

The duration of idling to charge the battery varies significantly depending on multiple factors. The level of battery depletion plays a crucial role: for mild discharge like slight power consumption from headlights, 10-15 minutes may suffice, whereas deep discharge caused by cold weather or aging might require 45 minutes to 2 hours. The health of the charging system is equally critical—faulty alternators or voltage regulators can slow charging to a crawl. Safety concerns must be highlighted: prolonged idling produces carbon monoxide, posing poisoning risks in enclosed spaces like garages, coupled with inefficient fuel consumption (~0.5L/hour). Charging efficiency is low since idling generates only 10-15 amps, far below driving conditions. Personally recommended as a temporary solution; driving briefly at high RPM or checking battery health is preferable. Maintaining the alternator and wiring connections prevents charging delays.

[MadelineLee]

Idle charging duration varies from approximately 20 minutes to 1 hour, primarily depending on battery condition. For slight power loss like post-start replenishment, 15-20 minutes might suffice; severe power deficiency or aged batteries may require over 1 hour. The reason is straightforward: low engine RPM limits alternator output to about 10 amps, resulting in slow charging. Higher temperatures accelerate charging while winter cold slows it down. A quicker method involves driving at highway speeds for several minutes - the charging current exceeds 40 amps, proving more efficient and economical. Generally avoid frequent idle charging as it wastes fuel, emits pollutants, and causes engine wear; regular battery maintenance extends lifespan and prevents hassles. Use a voltmeter to monitor charging status as precaution; adopting the habit of charging while driving is advisable - avoid prolonged idling.

[VanIsabelle]

I've encountered battery issues several times, and the idle charging duration is really inconsistent. For example, my friend Xiao Chen's car took 50 minutes of idling to recharge after being parked for a week, but he later regretted not just driving two kilometers, which would have been more time-efficient. Generally, a lightly depleted battery takes about 15 minutes to recharge, while a severely depleted one may require 30 minutes to an hour. The battery's age plays a decisive role—older batteries charge less efficiently due to degradation. Seasons also affect charging speed, with faster charging in summer and slower in winter due to the cold. The lesson here is not to rely too much on idling for charging, as the engine's low RPM results in a weaker output current—around 10 amps, which is less than half of what you'd get while driving. A safety reminder: prolonged idling increases exhaust fumes, posing health risks. It's advisable to opt for a short drive for more efficient charging or use a battery charger as a backup. Regularly checking battery fluid levels or signs of aging is the right approach to prevention. Avoid wasting resources by ensuring lights are turned off properly in daily use.

[OwenLynn]

The idling charging time can range from 15 minutes to 1 hour depending on the battery's discharge level: shorter for mild discharge and longer for severe discharge. The charging system's health, such as the alternator, directly affects efficiency, with idling current being only 10-20 amps, much lower than the 40+ amps when driving. From an economic and environmental perspective: idling for an hour consumes about 0.5 liters of fuel—small in cost but wasteful in resources and increases pollution emissions. Alternative solutions include driving at high speed for a few minutes to charge quickly or using a smart charger for safe and controlled charging. Temperature and battery age also play significant roles: old or cold batteries charge slowly, while new or warm ones charge faster. Regular voltage checks can prevent faults and save hassle. For safety, ensure proper ventilation to avoid CO poisoning. Overall, idling charging is inefficient and recommended only for emergencies, not as a regular practice. Maintaining the battery well reduces the likelihood of issues.