Reconditioning a Car Battery at Home — How to Do It Yourself

Are you having trouble starting your car in the morning? Do you hear your starter motor when you turn your key, but the engine won’t start? Are your headlights extremely dim or not working at all? If that’s the case, your car battery might be drained.

But there’s no need to worry; replacing a faulty car battery doesn’t have to cost an arm and a leg. With just a few tools and some tricks, you can recondition your car battery at home in no time. The techniques I’m going to show you are fool-proof and will save you a lot of money in the future.

How to recondition car battery at home.

Why Do Car Batteries Fail?

More often than not, a car battery dies because it didn’t have enough water to recharge. And the reason it didn’t have any water is because of high temperatures, overcharging, or lack of maintenance. Here are a few of the most common reasons for car battery failure and how to prevent drainage in the future.

1. Extreme Weather Conditions

According to most car manufacturers, the ideal temperature for a car battery is 80°F. At this temperature, your battery is at its optimum state and works at maximum efficiency. If your car battery is running low on electrolytes, it can freeze at 30°F. On the other hand, extremely high temperatures can accelerate evaporation and corrosion on your battery.

2. Faulty Starter Motor or Charging System

A worn-out starter motor will drain your car battery and draw excessive amounts of high current from it. What’s more, faulty alternators or regulators might be another reason why your car battery died. If the output voltage is too high or too low, you’ll end up with a flat battery in a matter of days or weeks.

3. Loose or Worn out Terminals

You have to clean and tighten your battery terminals on a regular basis. Otherwise, they’ll drain your car battery. A loose battery post can even melt or make your terminals explode while you’re driving. It’s a big safety hazard, so make sure they’re always tight, dry, and clean.

Diagnosing the Problem

There are five telltale signs that your car battery is drained and that you need to recondition it. First, if the dome light doesn’t turn on and there’s no door chime as soon as you open your car, you probably have a dead car battery.

Another sign could be if your headlights have stopped working and won’t turn on. You could be dealing with a faulty or empty car battery if your car won’t start in the morning, but does so later in the day. And if you hear the starter motor when you turn the key, but the engine won’t start, chances are — the battery’s dead.

Reconditioning Your Car Battery at Home

To successfully recondition your car battery at home, you’ll need a few supplies, a couple of tools, and good old-fashioned elbow grease. To start off, here’s a checklist of everything you’ll need:

  • Safety goggles
  • Apron or old clothes and closed-toe shoes
  • A pound of Epsom salt
  • A gallon of distilled water
  • Plastic bucket
  • Flathead screwdriver
  • A funnel
  • Neoprene chemical-resistant gloves — If you want to buy disposable gloves, I recommend the Ammex Nitrile Gloves. On the other hand, if you want something reusable, go for the ThxToms pair.
  • Voltmeter — The two best voltmeters I’ve found on the market are from AstroAI and Etekcity. Both of them cost pretty much the same, so it’s all up to your personal preference.
  • Post cleaner brush — You don’t have to buy a post cleaner brush, but I just find that it’s much easier to work if you have one. My favorite is Schumacher’s brush because it’s cheap and gets the job done.
  • Car battery charger — Depending on your budget, there are two car battery chargers I recommend. If you want a durable and reliable model, you should get the Battery Tender Plus. But if you’re looking for something with extra features, you can buy the battery charger from Schumacher.

1. Clean the Corrosion

Before you can start reconditioning your car battery, you’ll have to do some prep work. First, you’ll have to clean your battery posts from any corrosion that might have built up. If you don’t have a post cleaner brush, you could make a solution at home. All you need to make it is some baking soda and water.

Take two tablespoons of baking soda and start pouring the water in, until you have a paste-like consistency. Then, take a toothbrush and rub the solution onto the posts. If you see foam coming from the solution, that means it’s working and lifting the corrosion off your terminal posts.

If the corrosion persists and you can’t take it off with just a toothbrush, you can go in with steel wool or even fine-grit sandpaper. Once you’ve made sure that the posts are clean, take a dry rag or cloth and wipe the excess solution away.

2. Check the Voltage

Now, it’s time to check your battery’s voltage to see if it even can be reconditioned. Take your voltmeter and hook it up to the terminals. If you see a reading of 12.6V, that means your battery is in good condition and the corrosion was causing the problems.

But if the readings are between 10V and 12V, you’ll need to recondition your battery. It’s also possible for the voltmeter to show a reading of zero. If you see that, your battery has probably short-circuited and you’ll have to get a new one.

One thing to keep in mind about reconditioning batteries at home is that it can only work three out of five times. If you aren’t able to bring your battery back to life with this method, it’s probably time to buy a new one.

3. Take the Acid out

Before you can take the acid out, make sure to put on your safety goggles, gloves, and protective clothes. Use your flathead screwdriver and slide it under the battery caps to remove them. Most cars have two or three caps, but some can have up to six. It’s key that you take all of them off in order to take the acid out.

Before you start pouring the acid out, make sure your bucket is close to you because you’ll need to work fast. Once you’re certain that there’s no more acid inside the cells, pour half a pound of baking soda inside the bucket to neutralize it. You can pour the neutralized acid down the drain, while you’re running cold water.

4. Cleaning the Car Battery

Now that the battery is empty, it’s time to clean the cells using baking soda and distilled water. Take half a gallon of water and half a pound of baking soda and mix it in a bucket or another container. Then, use a funnel to pour the solution into every individual cell of your car battery.

Once the solution is in, put the caps back on and shake your car battery for about 30 seconds to a minute. You can pour the solution into the bucket of acid you’ve already neutralized and dispose of it.

5. Reconditioning the Car Battery

Now that your battery is clean, you can start reconditioning it with an electrolyte solution you’ve made at home. For the solution, you’ll need distilled water and Epsom salt. Put half a pound of salt in a bucket and start pouring half a gallon of boiled distilled water over it. Stir the solution for a while, until all of the salt has dissolved.

Take a funnel and start pouring the solution into every single cell in your car battery. Make sure you’ve filled them all the way up to the top, otherwise the solution won’t work. Put the caps back on and shake your car battery for a minute or two. If you want to add more amperage, you can repeat this process a few times.

6. Charge Your Car Battery

To recharge your battery, take the caps off your terminals and get your car battery charger out. Put the charger as far away from the battery as the cables allow and make sure the charger isn’t on until you’ve connected it.

Connect your positive lead (the red cable) to your positive terminal, and do the same for the negatives. The safest way to charge your battery is by putting it on a slow charge of 12V for 24–36 hours.

Before you disconnect your battery, unplug the charger first to avoid any sparks. Take your voltmeter again and see what the readings are. If you have 12.6V, you’ve managed to recondition your battery. But if the reading is below 12.43V, you might need to charge the battery for another 12 hours.

Bottom Line

As you can see, reconditioning a car battery at home is not difficult at all. All you need is a few tools and a bit of patience to do it. Not only will reconditioning your car battery save you some money, but it’s also much better for the environment. Remember, you shouldn’t start working on your car battery until you put on all of the proper safety equipment. Also, keep in mind that this method won’t work if your battery has short-circuited or if you’ve already done it more than three times.

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