How To Fix A Car Battery



Before considering the question of how to fix a car battery, we have to think of whether or not it’s even possible in some cases. There are many different methods, from chemical-based techniques to inducing specific electrical impulses during the charging process. But which method truly works, and which one is more practical to try? 

Can You Use a Basic Car Battery Charger?

There comes a time when even jump starting a battery or using a charger no longer has any effect. While most people just replace and recycle it, some prefer to figure out how to fix a car battery to get some more juice out of their old unit. Sadly, using most types of chargers simply won’t cut it. When the active material (for example: acid in lead-acid batteries) is unable to maintain a great enough charge, the battery dies, and no amount of sustained, continuous DC charging will change that. Some pulse charging techniques are believed to be more effective when it comes to reviving dead batteries, but great care has to be taken not to damage the battery further.

Advance Auto Parts stores offer free battery testing and installation*.

Fix Car Battery with Acid and Water

A safer and more effective way of how to fix a car battery is by simply topping off its distilled water and acid levels. This method only works in the case of lead-acid batteries and should be handled with extreme care due to the toxic nature of car battery acid. By filling up a wet cell lead-acid battery with the right amount of water, you can get it to work again even if it was unable to create a sustainable charge in the past. However, it’s important to avoid adding acid unless the battery actually had some of its acid spilled out. Otherwise, topping it off with distilled water and using a charger to mix the acid and water should suffice. Keep in mind that most newer batteries are a sealed-cell design, and topping off the electrolyte levels in the cells isn’t even possible.

To complete this method, you have to first measure it. If it’s completely gone, the voltage it gives off will be minimal. The next step is to top it off with distilled water (if possible) in order to activate the acid. You may find the voltage increasing slightly after this step. If acid was spilled, the right amount of sulfuric acid should be added to supplement it. Otherwise, after adding distilled water, simply kickstart the charging process and allow the chemical reaction to take place, so the dried acid can once again mix with the water.

Take a look at some popular battery accessories

What is Sulfation

The normal life span of a car battery is about 4 years and knowing how to fix a car battery effectively may increase that number. If you own a fairly good quality lead-acid battery, you can use the acid and water method several times, but after some time, a process known as sulfation kicks in. This is when the battery’s plates gradually build up residue that makes them less and less capable to react. The sulfation process is accelerated the more you renew the acidity of the electrolyte.

Even so, learning how to fix a car battery could improve your old battery’s life span at least until you’re able to find a suitable replacement. Just remember this — if you’re having to take these kinds of steps to keep a battery usable, it’s already on borrowed time, and you’re going to have to consider replacing it sooner rather than later.

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*Car battery testing and installation available on most automotive vehicles, at most locations, unless prohibited by law.

Last updated September 23, 2021