The battery on the Wife's Golf is flat after standing idle for 3 weeks, can I safely jump start it from the positive negative terminals under my bonnet on my E350 Coupe, any does and donts info very welcome 
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Check your handbook for the specific recommendations.
There is usually a large terminal for attaching the Positive lead too, not the battery terminal.
Ensure a good earth connection for both cars, the engine casting or similar works well.
There is usually a large terminal for attaching the Positive lead too, not the battery terminal.
Ensure a good earth connection for both cars, the engine casting or similar works well.
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Ideally a car should be jump-started from a car battery that is not connected to another vehicle.
This is because jump starting from another vehicle can cause damage to the electronics of either car.
You could also try a jump starter - the device you connect to mains to charge it first, then connect it to the car battery - there's still a risk of damage to electronics but this way it is limited to just one car.
Said that, I have jump started vehicles from another vehicle, taking the risk of damaging the electronics, in situations where I had little alternatives or options.
When you do that, connect the two earths (black) first (body to body), and connect the positive (red) lead on both sides last just before starting.
Once done, disconnect the positive lead (red cable) immediately on both sides while taking care not to touch anything with the positive lead.
Another tip is not to use the cheap thin cables that you buy in petrol stations - they have high resistance and may overheat melting the insulation, or just not deliver enough power to start the engine. Make sure you use professional heavy duty leads.
This is because jump starting from another vehicle can cause damage to the electronics of either car.
You could also try a jump starter - the device you connect to mains to charge it first, then connect it to the car battery - there's still a risk of damage to electronics but this way it is limited to just one car.
Said that, I have jump started vehicles from another vehicle, taking the risk of damaging the electronics, in situations where I had little alternatives or options.
When you do that, connect the two earths (black) first (body to body), and connect the positive (red) lead on both sides last just before starting.
Once done, disconnect the positive lead (red cable) immediately on both sides while taking care not to touch anything with the positive lead.
Another tip is not to use the cheap thin cables that you buy in petrol stations - they have high resistance and may overheat melting the insulation, or just not deliver enough power to start the engine. Make sure you use professional heavy duty leads.
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rockits
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I have a nice RavPower battery pack that is small & works really well to jump start any cars. Normally 69.99 on Amazon but often they have them on a cheaper deal. I paid 45 I think.
