BMWs are sophisticated, stylish, and powerful vehicles with equally powerful batteries. However, if you’ve recently taken a look at your BMW’s battery, you may have noticed rust forming in its terminals. This rust can be caused by a number of factors and is almost always a sign that your vehicle’s battery should be replaced as soon as possible.
As you may have noticed, battery terminal corrosion often looks rather different from the rust you might find on the outside of a vehicle. Whereas the latter is usually a dull red, the former may be white or bluish-green. This is because external rust is usually caused by the iron in road salt, while battery terminal corrosion can be caused by a variety of different chemicals, including electrolyte, copper sulfate, and hydrogen. If enough of these chemicals build up on the terminals of your vehicle’s battery, then can prevent your BMW from operating altogether.
Your BMW’s battery is a complicated component that uses considerable amounts of the chemicals mentioned above. Accordingly, there are several circumstances that might lead to battery terminal corrosion. Battery terminal corrosion can often be caused by hydrogen leaks. The reactions in your BMW’s battery produce minute amounts of hydrogen gas, which is harmless to breathe but can cause corrosion when mixed with other substances. Depending on where on the battery this type of corrosion occurs, it can cause your vehicle to overcharge or undercharge.
Interestingly, overcharging alone can also lead to battery terminal corrosion. If your BMW’s battery is overcharged, its internal temperature will increase, causing the electrolyte within to expand. When the electrolyte runs out of space within the battery, it will force its way out of the battery through any available cracks or vents. Often, these vents will form near the terminals, and when the electrolyte seeps out of them, it will combine with the metal in the terminals to form corrosion.
Adding too much water to your BMW’s battery can cause a similar problem. Again, when the electrolyte in your vehicle’s battery is heated, it expands to fill empty space within the battery. This happens whenever the battery is in use. However, if there is too much water in the battery, the electrolyte will lack the necessary space to expand and will, again, expand through any cracks or vents in the battery. Therefore, when refilling your vehicle’s battery, you should be sure not to add too much liquid.
Another potential cause of battery terminal corrosion is the formation of copper sulfate on the clamps that connect your vehicle’s battery to its wires. Copper is a highly conductive metal that rarely corrodes. However, when it is exposed to both electricity and the sulfuric gases that can emerge from a battery, it reacts by creating copper sulfate, a substance that is very corrosive. Not only can this substance eat away at your vehicle’s battery terminals, but it is also a terrible conductor, so if your BMW’s battery experiences this type of corrosion, there is a chance that the vehicle might be unable to start.
All of the above factors can be made worse by battery age. The longer your BMW’s battery is in use, the more likely it is to develop leaks and cracks through which electrolyte and hydrogen can escape. Therefore, you should be sure to change your BMW’s battery every five years. Additionally, you should be sure to regularly take your BMW to a professional mechanic for routine maintenance. Doing so will help you to identify and fix any corrosion-related battery issues before they can cause serious damage to the rest of your vehicle.
If you’re looking for an experienced technician to maintain, fix, or replace your BMW’s battery, look no further than Ultimate Bimmer Service. For the past 30 years, our team has provided exceptional service to BMW owners in Carrolton and Dallas, TX.
We have a special passion for BMWs, and we would love to help you keep your vehicle running at its optimum performance level. So give us a call today, or stop by our shop to see what our BMW trained specialists can do for you.