Safely Disconnect your Battery
The purpose of the battery in a regular gasoline or diesel powered vehicle is to store enough electrical power to start the engine on a bitterly cold morning. This article describes why you might need to disconnect the battery and sets out a safe procedure for doing so. It does not relate to the type of batteries used in hybrid or electric vehicles like the Prius, Volt or Leaf.
There are two reasons for disconnecting the battery: to ensure that other vehicle maintenance work, especially on the fuel system, can be carried out safely, and to remove it from the vehicle, either to be charged or replaced. However, since it stores a lot of energy, the battery has the potential to cause serious injury, as described in thiscautionary talefrom Popular Mechanics. For this reason it is important that the battery be disconnected in the right way.
In most vehicles the battery is located under the hood where it’s easily accessible. There may be a cover over the top but it should be possible to spot two thick cables, one black, the other red, running into the enclosure. Some cars do however put the battery under the back seat or in the trunk.
Having located the battery, put on a pair of safety glasses. These will protect your eyes in case of any spills or sparks. You should also take care to never create an electrical short circuit between the two terminals, as would happen if you touched them simultaneously with something conductive like a screwdriver or wrench.
In some vehicles it will be necessary to remove some covers, and possibly even the air inlet duct, to gain access to the battery. With these out the way, locate and undo the hold down clamp that secures the battery to the vehicle. This will be down low at the base of the battery.
On the top or side of the battery will be two terminal posts to which the red and black cables are attached. These must be disconnected from the battery in the right sequence, a point stressed on the website of auto parts retailerNAPA. Undo the negative cable, colored black, first and remove it from the battery. Next, undo the red cable and again, pull it away.
Now that the battery has been disconnected, it can be lifted out. (If the disconnection is just to allow other maintenance work to be performed safely this step can be skipped.) There may be a strap on the side of the battery to lift with, but take care with this because batteries are very heavy and back injuries are a real possibility.
With the battery out it’s a good idea to make sure everything is clean, especially the tray in which the battery sits. This can be done with a mixture of baking soda and water. If the old battery is to go back in to the vehicle, take the opportunity to clean up the terminals by scrubbing gently with a stiff brush. Remember though not to create an electrical connection between the terminals! Then, when all the work is finished or a new battery has been purchased, installation is just the reverse sequence of steps.
The battery is an essential component of the modern motor vehicle and needs to be disconnected prior to replacement or performing other maintenance jobs. NAPA provides a goodguide to battery service, and if you’re interested in learning more about car battery construction and function, there’s a great article on theEdmunds.comwebsite.
