After jump-starting your car, it's generally recommended to let the engine run for approximately 20 minutes. This allows the charging system to replenish the battery and ensure it has regained enough charge to start the car on its own later. However, the exact time needed may vary depending on factors such as the condition of the battery and how much charge it has regained during the jump-start.
It's important to note that while running the engine, you should also engage in some activities that put a load on the electrical system, such as turning on the headlights or air conditioning. This helps to draw power from the alternator and further charge the battery.
If you have concerns about your car's battery or its ability to hold a charge, it's advisable to have it tested or inspected by a professional. They can provide more specific guidance based on your vehicle's condition and recommend any necessary repairs or replacements.