A flat car battery can really ruin your day. The problem always seems to occur when you are already running late and miles from home. With the appropriate knowledge, however, you can get your car up and running again quickly. Depending on your circumstances, you can try a couple of different remedies. Provided the battery is able to hold a charge and there are no other underlying problems, getting your car going again shouldn't cost you anything.
Use jump leads to harness the power of another vehicle's battery.
Ensure that the car you are jumping from is close enough to your own vehicle for the cables to reach easily between the two. Pop both bonnets. Ensure that both cars are in neutral or park, have their emergency brakes on and their engines turned off.
Connect the red, positive cable to the positive terminal on the battery in the car with the good battery. Attach the other end of the positive cable to the terminal on the car with the dead battery.
Connect the black, negative lead to the negative terminal on the donor battery and attach the other end to the chassis or frame of the car with the bad battery (to act as a ground). Choose a point unconnected to the ignition or fuel systems of the car.
Leave the cars connected in this way for three minutes,and then start the engine of the donor vehicle. Allow it to run for one minute before turning on the ignition of the car with the flat battery.
Leave the cars connected while running the engine of the car with the flat battery for at least 10 minutes, with the throttle slightly open. Then turn off both engines before disconnecting the battery leads, reversing the order in which they were connected as you do so.
Turn off any unnecessary electrical equipment before trying to push-start your car. Anything in your car that uses electricity will be drawing power that would otherwise be available to the starter motor, so ensure that the radio, air conditioning and (if safe to do so) lights are switched off. This method only works on a car with a manual transmission.
Get a friend or passer-by to push your car while you steer. In order to facilitate this, ensure that the emergency brake and foot brakes are off.
Put the car into second gear, but keep the clutch depressed. Turn the key as far as it goes without engaging the starter motor. When you reach a speed of 5 to 10mph, quickly lift the clutch. This engages the wheels with the engine and their rotation will start the engine. Depress the throttle slightly as this happens. Be sure to depress the clutch again quickly after the engine fires, in order to avoid stalling.
Ensure that you drive the car with no unnecessary electronic equipment active for a while. If there are no underlying problems with the alternator or the battery, driving the car will recharge the battery and save you from having the same problem the next time you stop. With the radio and air conditioning draining the available power away from the battery, however, this will take longer.
Do not try to jump-start a car whose battery appears to be damaged. Be sure not to let the donor car and the car with the flat battery touch each other. Do not smoke while jump-starting a car, and be sure not to touch either battery with metal tools or jewellery. When connecting or disconnecting the jump leads, take car not to let them touch each other or parts of the car other than those to which they are being connected. When push-starting a car, remember that the usual rules of the road apply and be sure not to contravene them. Look out for other road users.