Part 1. Preparation and safety
Objective
- Clean and replace an automotive battery.
Personal safety
Whenever you perform a task in the workshop you must use personal protective clothing and equipment that is appropriate for the task and which conforms to your local safety regulations and policies. Among other items, this may include:
- Work clothing - such as coveralls and steel-capped footwear
- Eye protection - such as safety glasses and face masks
- Ear protection - such as earmuffs and earplugs
- Hand protection – such as rubber gloves and barrier cream
- Respiratory equipment – such as face masks and valved respirators
If you are not certain what is appropriate or required, ask your supervisor.
Safety check
- Make sure that the hood is secure with a hood stay rod before going under it.
- Always make sure that you wear the appropriate personal protection equipment before starting the job. Remember, batteries contain acid and it is very easy to hurt yourself even when the most exhaustive protection measures are taken.
- Always make sure that your work area/environment is as safe as you can make it. Do not use damaged, broken or worn out workshop equipment.
- Always follow any manufacturer's personal safety instructions to prevent damage to the vehicle you are servicing.
- Make sure that you understand and observe all legislative and personal safety procedures when carrying out the following tasks. If you are unsure of what these are, ask your supervisor.
Points to note
- Always remove the negative terminal first when disconnecting the battery and fit the negative terminal last when reconnecting the battery.
- Automotive batteries can look lighter than they really are.
- If replacing a smaller battery with a larger one, replace the restraining device and tray used to secure the new battery.
- Be sure that you do not connect the battery up with reverse polarity because this could send an unwanted voltage spike into the electronic circuit and possibly damage the Electronic Control Unit (ECU).
- Disconnecting the battery will usually clear all the codes that are used to maintain the memory for the vehicle's on-board computer. This may erase all the radio presets and security codes.
- In some cases, the vehicle will even go into a type of "sleep" mode. This can prevent the vehicle from starting after the battery has been reconnected.
- Some manufacturers recommend connecting a 9-volt dry cell battery to the cigarette lighter with an auxiliary plug before the battery is disconnected. This should supply enough power to maintain the memory while the battery is changed over.
Part 2: Step-by-step instruction
- Disconnect battery
Always remove the cable clamp from the negative terminal first. The negative terminal is marked with a minus sign. Then remove the positive terminal, the one with the plus sign. You will later replace them in reverse order, positive cable first and then the negative cable. While they are unconnected, bend the cables back, or if necessary tie them out of the way, so that they cannot fall back and touch the terminals.
- Remove battery restraints
Remove the battery restraints or other hardware holding the battery down. Depending on the type of vehicle, you will need to unbolt or unscrew or unclip the restraint and move it away from the battery. Keeping it upright, remove the battery from its tray and place it on a clean level surface. You are now ready to inspect it.
- Visual inspection
Carefully wipe the battery with a clean cloth. It is best to wear rubber gloves while doing this in case any corrosive electrolyte has leaked from the battery. Then safely dispose of the cloth. If you see major cracks in the battery case or obvious terminal damage, the battery should be replaced regardless of its electrical performance. If the battery is not serviceable, don’t just dump it into the trash where it will be a hazard to the environment. Batteries are recyclable, and can be rebuilt and returned into service.
- Clean terminals
If there are powdery deposits on the terminals, clean them off. It may be enough to brush the deposits off the terminal posts and cable clamps with a non-metallic brush and a mixture of baking soda and water. Sprinkle the baking soda onto the terminal, dip the brush in clean water, and scrub the deposits away. If this is not effective, use a battery terminal cleaner and brush to provide a good, solid mechanical and electrical connection.
- Clean clamps
Examine the battery cables to see whether they are badly frayed or corroded. If the damage looks extensive, the cables and clamps should be replaced. Clean the insides of the cable clamps with the clamp cleaner that is usually supplied with a terminal brush. If you don’t have the correct brushes, use a soapless steel wool pad instead. Dry the terminals and clamps with a clean, disposable, lint-free rag. To prevent corrosive deposits from forming, coat the terminals with some anti-corrosion terminal grease.
- Clean the battery tray
Clean the battery tray with a mixture of baking soda and water, or some other approved cleaning solutions using a small non-metallic brush. Wipe the tray clean and dry, then replace the cleaned and serviceable battery. Replace the restraints and make sure they are holding the battery securely in position. If a new battery is to be installed be sure to compare the outside dimensions as well as the type of terminals and their locations prior to installation. These MUST meet the original manufacturer’s specifications.
- Reconnect the battery terminals
Reconnect the battery terminals, Positive first, and then Negative. Test that you have a good electrical connection by starting the vehicle.
Source: CDX Global
