How to keep your car battery in a good shape!

Last updated on 8 Dec 2022 by Thierry

People (and I am part of it) tend to forget that some batteries need maintenance, believing that once the battery is in place it will provide the energy to crank the engine of your car indefinitely, or up to when a cell inside it breaks down.
Can I maintain my car battery myself? Of course, read the car battery maintenance guide below!

The technical bit first…

A typical 12V lead-acid battery is made of 6 cells, composed of alternate plates made of lead alloy grids either filled with sponge lead or coated with lead dioxide. Each cell is immersed in electrolyte, which is a mixture of sulfuric acid (up to 40%) and distilled water.

During normal operation, part of the water is lost, through electrolysis process and evaporation. The sulphuric acid stays in the battery cell. The electrolyte levels are decreasing over time.

If the electrolyte levels are too low, the plates gets exposed to the air and a process called sulfation starts. Sulfation is a chemical reaction that interferes with the normal operation of the cells and will shorten the life of the battery, and maybe letting you stranded in the middle of nowhere!

So if your battery is not a sealed one (meaning with filler caps on top or some type of cover), you are able to check the electrolyte level and top it up when necessary to keep your battery operating at its full potential.

Important: for normal topping-up operations, use only distilled water, and nothing else as this can instantly damage your battery. No salted water, baking soda, or any other type of electrolyte. Not even sulphuric acid!

… And now the step-by-step car battery maintenance guide!

So now, the big question. How to do this maintenance operation? Is it difficult?

Don’t panic, that’s fairly easy, be reassured!

However, if you do not feel confident with performing the steps described below, please look for help from a knowledgeable person or a professional. Also, this post aims to give basic information and guidance and presents what works for me. You are using this guide on your own responsibility.

One can perform the checks and maintenance directly with the battery fitted on the car, or out of the car like the example presented in this post. If you’re choosing to take the battery out of your vehicle, you may want to have a look at this detailed guide. Whatever your choice is, you have a few precautions to take:

• If fitted on the car => the car shall be switched off completely
• If fitted on the car => disconnect the negative terminal (black)
• Wear protective equipment, such as gloves, safety goggles and old clothes,… as the sulphuric acid in the battery is very corrosive!
• No smoking
• Finally, be careful not to touch the electrodes of the battery.

Cleaning!

You need to start this maintenance with a good cleaning of the battery. It is important to remove any traces of battery acid, dirt, and dust. You don’t want anything to fall into the battery, as this would damage it irremediably. Moreover, dirt, dust, and acid deposit on the battery make it discharge itself by creating leakage currents. A clean battery is essential.

Checking the levels

To add water to the cells of a standard non-sealed lead-acid battery, first, open one of the filler caps (plastic screwed cap or some kind of cover). By looking inside, you will see the metallic elements making the cell, and hopefully some liquid. The liquid is the electrolyte.

Add some distilled water

If the metallic plates are not exposed to the air, jump to the next step.
If the metallic plates are exposed to the air, add just enough distilled water to cover the metallic components (2-3mm). Not more. This is because the electrolyte will expand during charging and is more likely to overflow if you’ve already topped it up before charging.

Finally, wipe up any spills, put back and tighten the filler cap, and proceed to the next cell.

Charge your battery

Once you have inspected each cell, you can charge your battery (refer to the notice of the charger you use).

You can check if you need to charge the battery by using a voltmeter, by connecting the negative lead (usually black) to the negative terminal of the battery and the positive lead (red) to the positive terminal of the battery.

The readings displayed can give you good information. Everything between 12.4 to 12.8 volts indicates a battery in good shape. Everything below 12.4 or above 12.9 volts is a sign of an issue. You should charge your battery if the reading is under 12.4 volts.

Check the levels… Again!

Once your battery is fully charged (meaning the voltage is now OK and you have disconnected the charger and let the battery rest for a few minutes), you can repeat the top-up cycle. This time, cover the plates with about 1cm of electrolyte, or as per marks on the outside of the battery if available/ visible. Some batteries have a couple of little notches at the bottom of the filler tubes. In this case, the liquid should just touch the bottom of the tube.

Last warning: be careful not to put too much fluid, or it will leak from the battery into your engine bay!

And you are done!

This should complete your maintenance cycle. That was not a big deal, right?

So now, the last tip to this car battery maintenance guide to keep your battery in good condition is to transform this check into a maintenance routine, ideally monthly, but I would say every three months is acceptable, pending on how you are using your vehicle.

Any questions about battery maintenance, please leave a comment or send me a message via the contact page or drop me an email. I will respond to you!