How Long Should You Keep the Engine Running After a Jump Start?
2 Answers
You should keep the engine running for at least 30 minutes after a jump start to ensure sufficient battery charging. A dead battery could be due to complete discharge or potential battery damage. If the battery is simply drained, you can attempt to start the vehicle using another car and jumper cables. However, if the battery is damaged, immediate repair or replacement is necessary. When jump-starting, only use a power source that matches the voltage of the rescued vehicle's battery to avoid damage. Incorrect connection or disconnection order of jumper cables may cause short circuits and vehicle damage. When removing jumper cables, always disconnect the negative terminal first, followed by the positive terminal.
I've been driving for over a decade. After a jump start, never rush to turn off the engine – let it run for at least twenty minutes or longer. The alternator needs time to recharge the battery while the engine is running, as the acid reaction inside the battery requires time to replenish. If you shut it off immediately, the battery may not have recovered enough power, making a subsequent restart likely to fail. I learned this the hard way one winter when I helped a neighbor jump-start his car, drove for only five minutes, and then turned it off – his car stalled again, wasting all our effort. It's best to take a short drive or run some errands until the warning lights return to normal before parking. Afterwards, I recommend checking whether the alternator and battery are aging to avoid long-term issues affecting daily driving.
