How to Jump Start a Car with Dead Battery?
4 Answers
The method to jump start a car with a dead battery is as follows: 1. Turn off the engine; 2. Take out the positive and negative cables of the jumper wires; 3. Remove the clips to open the battery protective cover, exposing the positive and negative terminals of the battery; 4. Connect one end of a jumper cable to the positive terminal of the dead battery and the other end to the positive terminal of the live battery; 5. Take another jumper cable, connect one end to the negative terminal of the live battery, and then connect the other end to the engine block or body of the dead car. Remember to connect negative to negative; 6. Start the car with the live battery. The reasons for a car battery dying are: 1. The alternator is damaged and cannot charge the battery; 2. The car's electrical appliances were not turned off; 3. There is a short circuit in the car's wiring.
Jump-starting a dead battery isn't actually difficult, but getting the sequence wrong by even one step could fry your car's computer. Here's how I've done it several times: First, park a donor car with a good battery close by, and turn off both engines. Take out the jumper cables, remembering that red is positive and black is negative. First, clamp the red clip to the positive terminal (marked with a +) of the dead battery, then clamp the other end to the positive terminal of the donor car's battery. Next, clamp the black clip to the negative terminal of the donor car's battery, but never clamp the other end directly to the negative terminal of the dead battery! Instead, clamp it to an unpainted metal part of the car's frame, like an engine lifting lug bolt, to avoid sparks. Then start the donor car and keep it running at around 1500 RPM. Wait a few minutes before attempting to start the car with the dead battery. Once it starts, don't rush to remove the cables—first remove the black clips, then the red ones. Reversing this order could also cause problems. A special reminder: automatic transmission cars must be in Park with the handbrake on, while manual transmission cars should be in neutral. Always choose jumper cables with thick copper cores—cheap, thin cables can easily melt.
Last time I helped a neighbor jump-start their car, I learned a trick: Before connecting, use a wire brush to clean both battery terminals, especially if there's white powder—scrape it off thoroughly, otherwise the high resistance may prevent conduction. Connect the red cable to the positive terminals of both cars first, then clamp the black cable to the negative terminal of the rescue car, and the other end to the engine block of the dead car (a metal part far from the battery). This grounding position is safer than directly clamping to the negative terminal. Start the rescue car and rev the engine slightly to charge for five minutes before trying again. If the dashboard lights of the dead car don’t even flicker, the battery might be completely dead or there could be a short circuit—don’t force it in this case. Modern cars have lots of electronics, and improper operation can easily fry the ECU. Beginners should ideally record the process on video—if something goes wrong, there’s evidence for repairs. Remember to keep the cars from touching and avoid letting the jumper cables dangle near the pulley.
Don't panic if your car battery suddenly dies. It's crucial to open the hood and locate the battery position, as some vehicles have batteries in the trunk. Prepare jumper cables with insulated handles. First, connect to the positive terminal of the working car's battery, then to the positive terminal of the dead battery. For the negative terminals: after clamping to the working car's negative terminal, clamp the other end to unpainted metal parts like suspension strut towers or transmission housing on the dead car. Key point: The rescue vehicle must keep its engine running and turn off all electrical devices! Wait 2-3 minutes for power transfer. If the dead car makes clicking sounds when attempting to start, it indicates insufficient charge - charge for 5 more minutes. After starting, maintain RPM above idle and let it run for over 30 minutes. In winter below freezing, battery capacity drops by half, so jump-starting may take twice as long. For older cars with aging wiring, use a multimeter to check voltage difference before grounding.
