How to Refill a Car Battery

Maintaining your battery is an essential part of car ownership. Here's a guide on how to refill a car battery, including the safety steps and what to refill the battery with.
Written by Cheryl Knight
Reviewed by Carrie Adkins
It goes without saying—without a
, your car’s engine can’t run. Keeping your battery in good shape is an essential part of being a vehicle owner.
Here's how your car battery works, how you can check its water levels, and how you can keep your battery’s water levels at the proper level.
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How your car battery works

When you turn your car key or push the ignition button, a signal is sent to the battery and it converts the chemicals held within it into electricity.
This electrical charge is sent to the starter, which cranks your engine. In addition to this important function, your car’s battery also powers the lights and other accessories of your vehicle.
Most car batteries have six cells that generate 12-volts of power. There are two plates within each cell, one made of lead and one made of lead dioxide. These plates are submerged in sulfuric acid which behaves as a catalyst to create the charge needed to power your car.
Over time, this liquid evaporates, which can eventually lead to a dead battery. That is why it is essential that you refill your car battery as-needed.

How to check the water levels in your car battery

To keep your battery running at its best, you should perform occasional maintenance, including removing any corrosion and checking the water level within the battery’s cells. To check the water levels of the cells in your battery, perform the following steps.
Step 1: Locate the battery. Start by determining where your battery is located within the engine compartment of your vehicle. The year, make, and model of your car determines where the battery is located. Usually, it’s located at the front of the engine compartment.
Step 2: Clean and find the cells. Once you have access to the battery, start by cleaning the top of the battery, including any dirt, corrosion, and debris. You can also remove the port covers, which are located on top of the battery, to access the cells underneath. Clean around the ports as well.
It might be easier to remove the battery before cleaning and servicing it. This allows you to fully access the battery, which makes the cleanup of any accidental spills easier. If you remove the battery, you should consider connecting the car to an outside power supply.
Otherwise, you‘ll have to reset some of the electronics in the vehicle, including the clock, radio presets, and other systems.
Step 3: Assess the fluid levels. Once clean, use a flashlight to compare the fluid levels in each cell. Each cell should have an equal amount of fluid. For a low water level, look for an exposed plate within the cell. In a normal cell, the fluid should cover the plate by ½-inch. As long as the water level isn’t ½-inch below the plate, you can usually refill it. Otherwise, you may have to replace the battery.

How to refill your car battery

After determining which cells are low on water, you can refill them. Before refilling, you’ll need to gather the proper tools and materials:
  • Distilled water
  • Battery filler
  • Battery charger
  • Safety glasses and neoprene gloves
  • Clean cloths
Step 1: Put on protective gear. Start by putting on safety glasses to protect your eyes from any accidental splashes. You should also put on neoprene gloves to protect your hands from sulfuric acid.
Step 2: Fill the low cells. Use the battery filler and distilled water to refill the cells that are low. If the battery was weak or dead, only add enough water to cover the plates in the cells. Otherwise, fill each low cell to the maximum level (which is just touching the bottom of the filler tube).
Step 3: Clean up messes. Wipe up any spills and close the ports. Make sure the area around the ports is free of dirt before replacing the covers. Discard any materials used in clean-up, and wash your hands using soap and water.
Step 4: Recharge the battery. Next,
recharge the battery
using a battery charger. During this process, check the battery to make sure that none of the refilled cells overflow. If they do, clean up the overflow with a clean cloth.
Step 5: Reinstall the battery. Once the battery is charged, place it back into the vehicle. Start the vehicle to make sure the battery still works. Monitor your battery, checking weekly or monthly to ensure that there isn’t any further overflow.
Now that your battery is in top shape, make sure your car is protected from further damage with the right
car insurance
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