It is very important to regularly check your car battery electrolytes (which are not just water) for two reasons: firstly because they are subject to natural evaporation and secondly because a small amount of liquid separates into oxygen and hydrogen each time you charge. battery. Learning to safely check and top up battery fluid is a fundamental aspect of vehicle maintenance. Continue reading this guide where you will find all the detailed instructions to proceed, without neglecting your safety and the integrity of the car.
Steps
Part 1 of 4: Clean the Battery and Open the Cells
Step 1. Locate the battery
In most cars, it is enough to open the hood to gain access to this element.
- In some cases you can find the battery in the lower part of the engine compartment, between the bumper and the front wheels. Sometimes it is accessed from the underside of the car and therefore it will be necessary to disassemble it in order to check it.
- In most BMWs, Mercedes Benzes and a few other cars, the battery is located in the trunk, in a hidden compartment.
- It may also be located under the rear seats, as is the case with some Cadillacs.
Step 2. Clean the battery
Before checking the levels, clean the surface of the battery and remove any debris surrounding the terminals. This step is very important because you must prevent foreign material from entering the cells when you open them. Cleaning also slows or stops the corrosion process of the surrounding metal.
- For general cleaning of road grime and little corrosion, use an ammonia-based window cleaner. Spray it on a rag - not the battery - and wipe the surface. Alternatively, you can use kitchen paper, but remember to change it often as it breaks into pieces.
- Massive corrosion must be removed with a slurry of baking soda and water. Again you have to moisten a rag and not get the battery wet. In some circumstances it is necessary to repeat this step several times and at the end you can wipe off any residual bicarbonate with a cloth moistened with glass cleaner. Leaving traces of bicarbonate on the outside of the battery promotes and accelerates further corrosion of the terminals and metal.
- Do not be hasty in these operations, make sure that the cell caps are tightly closed while you clean. Prevents detergents from entering or seeping into the battery through the raised caps.
- Note: if you prefer, you can remove the battery from the car before cleaning and servicing it, and then install it at a later time. This procedure is safer, especially if your battery is in a hard-to-reach spot. However, disconnecting the cables will reset all or some electrical accessories (clock, radio, etc.). If you can do all the maintenance without disassembling the piece, then you will save a lot of time later.
- You can also unplug the terminals and soak them in a cup of very hot water. The heat will melt the corrosion leaving a perfectly clean surface. Make sure the terminals are completely dry before connecting them to the battery again.
Step 3. Open the cell caps
On the surface of the battery, you should typically see two semi-rectangular plastic caps that are used to seal the cells. You can remove them by gently prying with a plastic spatula or screwdriver. Try to lift them from different points along the perimeter if you run into difficulties.
- Some models feature six single round caps; in this case you just need to turn them anticlockwise and lift them.
- If your battery is labeled "maintenance free", it means it is not designed to be opened. The car manufacturer does not provide any topping up for this type of battery, which will simply need to be replaced when it no longer works.
Step 4. Continue cleaning if necessary
Removing the caps may reveal other dirt around the cells. In this case, clean carefully using a cloth moistened with glass cleaner.
- Don't use baking soda this time. Limit yourself to a small amount of ammonia cleaner and be very careful that nothing (cleaner, dirt, paper scraps) gets into the battery.
- Don't ignore this step; if the surface of the battery is clean, less corrosion is formed. This is an important aspect of the maintenance process to ensure the integrity of the connections.
Part 2 of 4: Assessing the Level of Liquid Present
Step 1. Compare the liquid levels in the cells
Look inside each opening to understand how much liquid is in each. In theory, the liquid level should be constant in each cell.
- If not, it is likely that you have accidentally filled one cell more than the others during a previous refill. This is a problem that can be easily solved by equalizing the quantities of liquid once the excess has been used up.
- If the levels are noticeably different, then there may also be small leaks of fluid or a crack in the battery body. In this case you have to replace it. If there are no noticeable leaks, fill the cells to the maximum safe level using only distilled water and do a second check after a few weeks to assess any major changes.
Step 2. Recognize a low electrolyte level
The amount of electrolytes is insufficient when any part of the metallic elements present on the bottom is exposed to air. If these pieces are not completely submerged, then the battery cannot operate at peak efficiency.
- Parts left dry will deteriorate within a few days.
- If the electrolyte level is only 1 cm below the top of the cathode and anode, add enough water to completely cover these elements so that the battery is still usable, albeit with a slightly reduced capacity. You will find further instructions in the third part of this article; if not, consider changing the battery.
- Insufficient fluid level could be caused by overload, and if so, you should check the alternator.
Step 3. Recognize a normal fluid level
It must be 1cm above the metal elements or 3mm from the edge of the fill tubes extending from the cell opening.
In this situation, you do not need to top up the battery. Just close the cell caps again and check the battery in three months
Step 4. Learn to recognize when the liquid is at the maximum safe level
In this case the electrolyte touches the base of the filling tubes.
- Most of these have a pair of notches at a point near the bottom of the tubes themselves. The notches make visible a meniscus (a small amount of water that is attracted to the edges of the tube) which takes on a classic "eye" shape when the fluid touches the base of the tube. If you don't see any meniscus, it means that the fluid level is below the bottom of the fill tube.
- The function of the meniscus is to let you know when to stop refilling. You may need a flashlight to clearly see its presence or absence.
Step 5. Please note that these references are only valid for lead-acid car batteries
If the instructions in this article conflict with the recommendations of the battery manufacturer or vendor, ignore them.
Also remember that batteries in golf carts, floor mops, and those with nickel and cadmium need special electrolytes
Part 3 of 4: Changing the Liquid Levels
Step 1. Use only distilled water to refill the battery cells
You can buy it in any supermarket. If the electrolyte level is low (the anode and cathode are exposed to air), then fill each cell to submerge these elements again. Then recharge the battery with the special tool or just drive the car normally for a few days. If the battery has a full charge, only top it up to the maximum safe level - the liquid must touch the base of the fill tubes.
- Grab a funnel, spray bottle, or cooking pipette for maximum liquid flow control and fill each cell to the maximum level. Be very careful that debris and dirt do not enter the battery.
- Tap, well, filtered water or any type of water that is not distilled would introduce minerals, chemical elements (such as chlorine) and other contaminants into the battery, reducing its life.
Step 2. If the battery is "dead" or too weak, do not completely fill the cells
In this case you should just submerge the exposed metal elements (or leave them as they are if the fluid is at normal level).
- When you charge a weak or non-functioning battery, the electrolyte level increases, so you should have some free space to allow for this expansion (this does not happen with a fully charged battery).
- Electrolyte levels also rise as the battery warms up.
Step 3. Wipe off any drops or splashes and put the caps back on
Check that each element is clean, without any residue and put the caps back on the cells.
- If you have mistakenly filled the battery too much, but the liquid does not overflow, the best thing to do is to stop and do nothing else. If the liquid has leaked from the battery, remember that it is acid and do not touch it with your skin or clothing.
- Clean the area with a rag or kitchen paper by blotting the cell opening. Prevents the cloth or paper from getting soaked that it drips onto other parts of the engine compartment or onto other objects. Rinse them immediately in a bucket of water. Wear gloves and do not touch the water with your bare hands.
- Once the job is done, throw the rinsed rag or paper towel in the regular trash. Pour the water down the drain, being very careful not to splash it all around. You have to prevent acid residues from falling on other objects. Finally, carefully clean everything that has come into contact with the liquid, using a rag dampened with glass cleaner.
- A wet battery should be checked every week for a full month to make sure there are no more leaks and, if necessary, clean up any residual acid as described above.
- The amount of sulfuric acid that has accidentally escaped with the liquid is likely to be minimal to interfere with the operation of the battery. Do not try to replace the lost one, because an excess of acid reduces the life of the battery and ruins it far worse than its deficiency.
Part 4 of 4: Take Proper Security Measures
Step 1. Protect your eyes with a safety mask
The electrolyte in the battery is sulfuric acid, so it is vital that it does not come into contact with eye tissue, as it would cause a lot of damage or even blindness.
- Contact lenses offer no protection and could even make the situation worse in the event of an accident. Likewise, normal eyeglasses are not adequate because they do not have side shields.
- For all these reasons, wear a protective, acid-resistant mask, which you can buy at any hardware store.
Step 2. Protect your hands with disposable gloves
Choose a material that resists sulfuric acid for at least a few minutes. This type of protection is also available in DIY and hardware stores.
- Latex and vinyl are not acid resistant for a long time. If you have opted for gloves made from these materials, take them off and change them immediately as soon as you feel they have become wet. Over time, splashes of electrolyte are absorbed by the material and reach the skin and burn it.
- Neoprene offers protection for an hour or more, but neoprene gloves are not easy to find in regular "do-it-yourself" stores. Remember that "nitrile" and "neoprene" are not the same. The former has a much lower resistance to sulfuric acid than latex and should not be used.
Step 3. Protect the skin
Wear old, long-sleeved clothing and closed-toed shoes to repair as much leather as possible. If drops of liquid fall on your clothes, the acid will consume the fibers within a week or two, leaving a hole. For this reason, use old clothes that you can afford to ruin.
Step 4. Know what to do in case of direct contact with the electrolyte
If splashes of acid get on your skin, wash it off immediately with soap and running water.
- If you feel a tingling or burning sensation on your skin, then a drop or splash of electrolyte may have reached it. A single drop is enough to cause a burn.
- You probably won't notice any redness or skin damage until it's too late. For this reason, you should always check yourself, take a break and wash immediately, rather than hoping for good luck.
- When finished, dispose of all gloves and rags properly. If you leave them in contact with other materials, you could cause damage.
Advice
- If you find yourself having difficulty, take the car to a mechanic. Most auto parts stores will run this service for free.
- When checking the battery, keep the surrounding areas clean and free of debris.
- Do not remove the battery caps while the engine is running.
- Protect your eyes, battery acid is very corrosive and you may go blind.
- Always wear safety glasses when checking and replenishing the liquid in the cells.
- Use a 2.5 cm wide plastic spatula to pry and open the cell caps. It is a tool that you can buy in any hardware or paint shop. Alternatively, use a screwdriver with an insulated handle, but be careful and do not accidentally touch other metal parts with the shaft. Sparks could be generated which in turn ignite the hydrogen in the battery.
- Clean the battery. Dirt attracts moisture, especially that which has been exposed to battery acid fumes, thereby reducing the conductivity of the elements. The current flowing on the external surfaces of the battery and through the encrustations facilitates the corrosion of the surrounding metal.
