How Long Should You Not Turn Off the Engine After a Jump Start?
3 Answers
Do not turn off the engine for 20 minutes after a jump start. Steps for jump-starting a car: Take out one cable; first connect one end to the positive terminal of the rescue car's battery, then connect the other end to the positive terminal of the rescued car's battery. Take out another cable, first connect one end to the negative terminal of the rescue car's battery, then connect the other end to a metal part of the rescued car's engine. Start the rescue car; then start the rescued car following the normal procedure. Quality of jumper cables: When purchasing jumper cables, choose genuine, quality-assured ones. Opt for thicker cables with an outer diameter of at least 10mm and a length of about 3 meters. Avoid cheap, low-quality jumper cables priced at just a few tens of dollars to prevent them from burning out due to inability to handle high starting currents.
I remember every time after giving someone a jump start, I would suggest keeping the engine running for at least 15 to 20 minutes before turning it off. This is because the alternator needs time to recharge the battery. Idling is acceptable, but it's even better to drive a short distance at around 60 km/h for more effective charging. The charging rate isn't very fast, and idling might take over half an hour to accumulate enough power for the next start. I've encountered situations where turning off the engine too soon resulted in the car not starting again after just five minutes, especially with older batteries. Regularly checking the battery voltage and maintaining it above 12.6V can help avoid this issue. Make it a habit to wait a while before shutting off the engine after a jump start. Additionally, battery performance drops in cold weather, so it's advisable to drive a few extra minutes to ensure safe operation.
As a guy who plays with cars every day, I'm quite familiar with jump-starting. After starting, don't turn off the engine, wait for about 10 to 15 minutes and it should be fine, driving a short distance is even better. Modern alternators are efficient, they can charge even when idling, but the speed is slower at low RPM; when driving, the engine runs faster and charges quicker. Use a multimeter to check the voltage, when it reaches 13.5V, it means the battery is almost fully charged. If the battery is relatively new, it can usually start again after 15 minutes; for older batteries or in cold weather, you might need to wait longer. It's recommended to try driving a few kilometers to get it done, saving both time and fuel. Don't forget to check that all electrical devices in the car are turned off before starting to prevent discharge issues.
