How to Fix A Weak Car Battery

Feb 19, 2020

How to Fix A Weak Car Battery

After around 2 years or so, you may find that your car battery can’t hold it’s charge like it used to. It can be hard to gauge a car battery’s lifespan; however, it can be estimated on average they will last 4-6 years. There is a way you can restore most of your car battery’s performance for a fraction of the cost of replacing it.

But before considering doing a DIY job, you must think if it’s even possible in your case. There are many different methods, from chemical-based techniques to inducing specific impulses during the charging process. What are the methods that work and are most practical to try?

Basic car battery charger

There will come a time where jump-starting or using a charger is not going to have an effect. While most people just replace and recycle it, some prefer to find a cheap way to fix a car battery and try to get some more power out of their old unit. Using most types of charger just won’t cut it, when the active material such as acid in lead-acid batteries is unable to maintain a good bit of charge, the battery dies.

Rejuvenate a battery by adding more acid

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 will only work in the case of lead-acid batteries and should be handled with extreme care due to care due to the dangerous and 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, avoid adding acid unless the battery had some of its acid spilt out.

Fixing car batteries with acid and water

To be able to revive the dead battery, you first need to measure it. If it is completely gone, the voltage will be minimal. Now it’s time to top it off with distilled water (if possible) to activate the acid. The voltage should then increase slightly after this step. If acid was spilt, the right amount of sulfuric acid should be added to supplement it. Once this is done, kickstart the charging process and allow the chemical reaction to take place.


As we mentioned, a normal car battery life span is estimated around 4 years and if you know how to fix a car battery or carry out prevention methods regularly, you can increase that number. When you have used the acid and water method a few times, eventually a process called sulphation will kick in and this is when the battery’s plates gradually build up reside making them less capable of reacting.

Where to get a car battery checked?

If you’re unsure about doing any of the methods yourself, you can always ask a local mechanic to have a look at the car battery for you. If you need help finding a trusted mechanic in your area, enter your reg number today with and we will handle the rest!


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