How to correctly put the battery in the car

Many vehicle owners install their car batteries themselves, often relying on intuition rather than following technical guidelines and safety standards. Incorrect battery installation can not only harm the vehicle but also pose serious risks to personal safety.

What You Need to Install a Car Battery

Before installing a battery, it’s essential to gather the proper tools and supplies. Depending on your vehicle’s model and the battery’s condition, you’ll need:

• Open-end wrenches or spanners (typically 10mm and 13mm, but this may vary)
• Pliers
• Utility knife (for stripping wires, if necessary)
• Emery paper (fine and coarse, for cleaning contacts and terminals)
• Anti-corrosion agents (lithium grease, solid oil, or silicone spray)
• Personal protective equipment (PPE) such as gloves and goggles
• Multimeter (for checking battery voltage)

Safety Precautions

The key risks when working with car batteries include:

• High currents in case of short circuits, which can cause sparking and overheating
• Exposure to harmful battery electrolyte
• The battery’s weight, which can lead to physical injury if mishandled

To minimize these risks, always follow safety protocols:

• Adhere to the correct installation procedure
• Wear protective clothing made from natural fibers
• Ensure footwear is sturdy, such as boots or work shoes
• Use rubber gloves and safety glasses to protect against electrolyte spills

Preparatory Steps

Before installing the battery, follow these preparatory steps:

① Clean the regular place of installation of the battery from dirt, dust, foreign objects. If you decide to supply a larger battery, you need to make sure that the fit is consistent. Note that during operation, the battery must be well ventilated, cooled. Otherwise, it can boil, especially in the warm season. Therefore, in the literal sense, "push" the battery under the hood should not be.

② Check the battery voltage, electrolyte level (in the serviced version). The voltage measured with a multimeter should be between 12.6 and 12.9 volts. If it is less than the lower threshold, the battery should be recharged. In stationary conditions, this is easier than on a car.

If you are installing a pre-owned battery, it is advisable to check the electrolyte density. At a temperature of 25 degrees Celsius, it should be in the range from 1.26 to 1.30 grams per centimeter cubic. A density meter must be used to control density.

If you purchased a battery of dubious quality, you can check its inrush current. This is done using a special load fork. Many sellers make a control measurement of current before transferring the goods to the buyer, and rightly so.

③ Assess the quality of contacts and terminals.If necessary, they must be cleaned: first with large, then with fine sandpaper. If it is missing, you can perform a knife stripping. The starting current depends on the quality of the contact - this is one of the main characteristics of the battery.

How to Install a Battery in a Car

To avoid short circuits or damage to the vehicle’s electrical system, follow these steps carefully:

① Install the battery in a regular place. Check that the polarity of the terminals matches the plus and minus positions on the battery. When installing in the dark, you can use the relief signs + and - on the battery. In addition, you should know that the positive output of the battery is thicker (19.5 mm) than the negative (17.5 mm). Three-level reverse polarity protection is not accidental. If you install the battery in reverse polarity, half of the fuses will burn out, the generator will fail, there may be serious problems with the electronics of the car.

② Fasten the battery to a regular place using a bracket or bracket.

③ Install a gas vent on the battery, if any. The gas outlet is usually installed if the battery is in the cabin or trunk. It is designed to remove gaseous products of charge-discharge processes from the battery.

④ Connect the terminals. Connection Sequence:

• put the positive terminal first (in this case, if the key that fixes the terminal touches the mass of the car, there will be no short circuit, since the negative terminal is still disconnected);
• install and fasten the negative terminal.

⑤ Perform a test run of the engine.

⑥ Treat contacts and terminals to prevent further corrosion.

Troubleshooting: What to Do If the Car Doesn’t Start

If the starter fails to turn over the engine, check the following:

• Inspect terminal connections: Ensure they are clean and secure. Reconnect if necessary.
• Check the grounding: Inspect the negative terminal’s connection to the car body or engine block.
• Consider battery capacity: If you’ve installed a smaller or older battery, it may not have sufficient power. In such cases, replace it with a new one.
• Reset electronics: If the battery has been disconnected for an extended period, the vehicle’s electronics may require resetting.

Restoring Settings After Battery Installation

In some vehicles, disconnecting the battery can reset electronic systems such as the onboard computer or car radio. You may see error messages on the dashboard. To resolve this:

1. Connect a diagnostic scanner: Use the scanner to read and clear any low-voltage errors.
2. Manually reset equipment: Restore settings such as radio presets manually if needed.