jump starting

[ericcs]

just a curiosity thing, when jump starting, why is the negative cable clamped to an engine/body part instead of the battery post like the red cable?

 

[Infernal]

It doesn't really matter where you clamp it, but the starter motor will pick up its earth from the engine block, so it saves running it through the chassis, to give the starter a better cleaner earth.

 

[tweak'e]

its actually more to do with generating sparks when you connect them and setting off the hydrogen gas coming out of the battery.
batteries can produce a lot of case if your cranking them hard.

 

[Old.Tony]

As above. If you're using a VRLA/AGM/sealed battery there's less concern about hydrogen escaping, but ALL batteries can emit hydrogen while charging. Dumping a full battery onto an empty battery will cause the empty battery to try charging very, very fast - and that produces lots of hydrogen. Even sealed batteries will release that if the pressure is too great, and you do run the risk of igniting this gas from the sparks as you disconnect the leads.

 

[Johnyalsdjiyo]

It doesn't really issue where you secure it, but the beginner motor will choose up its world from the motor prevent, so it helps you to save operating it through the framework, to give the beginner a better better world..............