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When trying to jump start my Volvo XC-60, I came across a very unexpected problem.

I tried to use our 2nd vehicle, a 2010 Ford Escape, as the assisting car to jump start mine. But when I looked at the engine compartment of the Escape, I found that the battery is positioned in such a way that the negative terminal is completely inaccessible and there is no physical method that I can find to connect jumper leads to that battery.

I was always taught to connect the jumper cables as follows:

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With + to +, and - on the assisting vehicle to a good ground point on the car with the dead battery.

But given that the negative terminal is not accessible, I did not want to try it. I eventually borrowed a friends car to jump start mine, but now I'm left wondering, is it possible to use the Ford Escape to jump start another car by hooking the negative lead to another location?

6

Any ground (earth) location will work. On my '06 Silverado, there are places to hook the jumpers which are away from the battery. You don't even hook the jumpers to the battery no matter which way you're going (whether jumping or being jumped). As long as you have a good ground location, you're golden. Given two vehicles with alternative connection points (places away from the battery), you could possibly have all four locations away from the battery and still be good. This may not be ideal, but it will still work.

As an aside, I was always taught the vehicle doing the jumping should be the last vehicle to be connected, and that the negative on it should be the one which is connected away from the battery. Either way you go, the one which is done last should be the one connected away from the battery. This is because when the last connection is made, the inevitable spark will occur. Batteries release hydrogen gas which can ignite from the spark. By placing the last connection away from the battery, you severely limit the chances of an accidental explosion (think of flames and battery acid going everywhere ... not a pretty thought).

  • Basically the last connection made and the first connection broken will spark. You want that spark as far away from combustible gasses as possible. The dead battery will likely be producing more hydrogen gas than the charged one, so making and breaking the connection on the charged vehicle is safer. In the old days of chrome-plated bumpers you only even needed one cable, you could touch the bumpers together for the ground connection. – Perkins Nov 8 '16 at 20:55
  • An advantage to doing last make/first break on the fully-charged vehicle is that if one is accidentally startled (e.g. by a bee sting), one is less likely to drop anything in such a way as to short out a fully-charged battery. Especially in the days when booster cables had a lot more exposed metal, I'd say the reduction in that risk was probably more significant than the reduction in explosion risk. – supercat Jan 12 '17 at 20:20
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As Paulster2 said, any bare metal should provide a good ground.

Most common places to attach leads in your situation would be a lifting eye (if your engine has them), the body of the alternator is normally easy to attach to, or any metal part of the engine.

Also make sure the metal you attach the lead to is capable of carrying enough current to start the car. This normally just requires some common sense, for example a small metal bracket attached with one tiny bolt could become very hot and al

1

AS mentioned. It is a shared ground (all exposed metal is a ground. So connect to any none painted metal. Though they normally have a bolt or something to attach to near the battery.

0

Often when vehicles have inaccessible battery terminals there will be specific jump start or charging terminals somewhere more convenient. This is often the case with vans which frequently have the battery located under the passenger seat.

These terminals are often located in the engine bay near the top of the bulkhead on the near (kerb) side usually under a clip on plastic cover. Alternatively there may be secondary terminals near the battery.

protected by Pᴀᴜʟsᴛᴇʀ2 Oct 25 '18 at 17:57

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