Vehicle shown in this step: 2022 BMW 750i xDrive 4.4L V8 Turbo
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Procedure notes
This video shows you how to use jumper cables to jump start a dead battery in your 2019 BMW M850i xDrive. If you get into your M850i xDrive, turn the key, and your car doesn't start (you may hear nothing or a clicking sound from the engine bay), you have a dead battery and need a jump-start. Check to see if you left your headlights or an interior light on and turn the switch off. Assuming that you have a pair of jumper cables, a pair of safety glasses and a friend to give you a jumpstart, the video above will show you where to connect the cables (and in what order!) for your M850i xDrive.
It is important to use the best jumper cables you can buy as they have thicker gauge (0, 2 or 4 gauge) wire and will impact how long to charge car battery with jumper cables (your M850i xDrive will charge faster with thicker cables). Cheap jumper cables have very thin wire such as 8 or 10 gauge), which increases how long it will take to charge the battery with jumper cables in your M850i xDrive. When you finish jumpstarting the dead battery car, which battery terminal to disconnect first is important. Be sure to disconnect the negative cable (black cable) from the ground on the dead car, then disconnect the negative cable from the ground on the donor battery, then disconnect the positive (red cable) from the donor battery and finally disconnect the positive cable from the dead car. Once you are finished reviving a dead car battery in your M850i xDrive, make sure you drive it for at least 5 minutes before turning it off so your battery isn't dead the next time.
So what's up with the safety glasses? There is a small possibility of a battery exploding during the charging process if you don't connect the cables properly (causing a spark) and there is a bunch of hydrogen gas around the battery (car batteries emit hydrogen gas when they discharge) - this is much more of an issue with cars that haven't been driven for a long time than if you drive your M850i xDrive regularly and simply forgot to turn your lights off.
查看中文对照 · Chinese translation
本视频演示如何使用跳线电缆为您的 2019 宝马 M850i xDrive 车辆中死掉的蓄电池进行搭电启动。 如果你进入 M850i xDrive，转动钥匙，车辆无法启动（你可能听不到任何声音，或听到发动机舱内的点击声），说明蓄电池已没电，需要搭电启动。 检查是否忘记打开了大灯或车内灯，然后将开关关闭。 假设你有一对搭电电缆、一副安全眼镜，以及一位可以为你搭电启动的朋友，上述视频将为你展示如何连接电缆（以及正确的顺序！）以完成你的 M850i xDrive 的搭电启动。
务必使用最优质的搭电电缆，因为它们采用更粗的导线（0 2 或 4 号）规格，这将直接影响通过搭电电缆为汽车蓄电池充电的时间（使用更粗的电缆时，您的 M850i xDrive 会更快充电）。 廉价的搭电电缆线采用非常细的导线，例如 8 或 10 格，这会延长使用搭电电缆在您的 M850i xDrive 上为电池充电所需的时间。 当你完成搭电启动死电池的车辆后，先断开哪个电池端子非常重要。 务必先将搭电启动车辆的负极（黑色电缆）从地面断开，然后将供电池的负极从地面断开，接着将供电池的正极（红色电缆）断开，最后将死车的正极电缆断开。 在完成对M850i xDrive车辆死电池的搭电启动后，务必在关掉发动机前至少驾驶5分钟，以确保电池下次不会再次失效。
关于安全眼镜的问题是怎样的？ 在充电过程中，如果未正确连接电缆（导致火花）且电池周围存在大量氢气（汽车电池在放电时会释放氢气），电池爆炸的可能性很小。这种情况在长时间未驾驶的车辆中更为严重，而如果你经常驾驶M850i xDrive，只是忘记关掉车灯，则风险较低。