Car Battery Reconditioning (A Step-By-Step Guide)
Looking for a mechanic near you for maintenance or repair? RepairSmith brings the shop to you. Get a free instant quote today.
Instead of replacing it with a new battery each time it died, you could get your car battery reconditioned. While this may not be possible for damaged or extremely old batteries, battery reconditioning is a common way to extend the lifespan of a battery.
In this article, we’ll answer both of those questions to help you with your lead acid battery. We’ll also go through some FAQs on battery reconditioning for added information.
This Article Contains
Battery reconditioning is the process of returning dead battery cells to full health and charging capacity.
But why is reconditioning even needed in the first place?The lead acid battery generates electrical energy through a chemical reaction between its electrolyte fluid (consisting of sulfuric acid and water) and lead plates.
Each time a battery discharges, lead sulfate crystals form on the battery plates. When the lead acid battery is recharged, the lead sulfate disperses.
However, not all of it goes away.
With time, the lead sulfate crystals build up, affecting the charging and discharging capacity of the battery. This condition is called sulfation.
Sulfation causes the battery to undergo longer charging times, have less charge capacity, and become less efficient until it eventually can’t hold a charge.
Here’s where battery reconditioning steps in.
The battery reconditioning process helps clean off the excess lead sulfate crystals in each battery cell and replenish its electrolyte solution, allowing the battery to function almost like new.
So, how is battery reconditioning done?
Lead Acid Battery Reconditioning (Step-By-Step Guide)
Battery reconditioning can be done on both a flooded lead acid or sealed battery.
It involves these seven steps:
Before you begin, there are a couple of things you need to get ready ahead of time.
Required Items
Here’s what you’ll need to have on hand.
- Protective gear (safety goggles, apron, chemical-resistant gloves, etc.)
- Toothbrush, steel wool, or battery terminal cleaner
- Flathead screwdriver
- Funnel
- Bucket
- Battery charger
- Voltmeter or multimeter
Safety Measures
To start, suit up with your protective gear. Battery electrolyte contains sulfuric acid, and you don’t want any on your skin or clothing. Make sure you work in a well-ventilated area in case of splashes, spills, or released fumes.
Check your car battery for any kind of damage — cracks, bloating, leaking. Don’t bother reconditioning a physically compromised battery. Get a new battery.
Check The Battery Voltage
Checking the battery voltage will tell you if the battery is viable for reconditioning.
The standard 12V car battery has six cells. Each battery cell generates a cell voltage of 2.1V, so a healthy battery reading will be around 12.6V.
Touch the voltmeter or multimeter (that’s set to read voltage) to the battery terminals — the red cable to the battery’s positive terminal and the black cable to the negative terminal.
The battery may be reconditioned for a voltage reading between 10V-12.6V. If it’s less than 10V, you have a completely dead battery and should replace it.
If all is fine, you’re ready to proceed with the reconditioning process:
Mix The Cleaning Solution
Mix the baking soda with distilled water to create a watery paste. The ratio should be 2:1 or 1:1 of baking soda to distilled water. Don’t use any other type of water (like tap water) as these may contain unsuitable trace minerals.
This solution will act as the battery cleaner and also to neutralize any acid spills.
Clean The Battery Of Corrosion
Detach the battery cables — negative (-) battery terminal first, then the positive terminal.
Apply the cleaning solution to any corroded battery terminal, then use the toothbrush or steel wool to scrub. Corrosion impedes the transfer of electrical energy, so it’s important to remove it from the terminals and cable connectors.
Alternatively, a dedicated battery terminal cleaner would also work here.
Empty The Battery Cells
Remove each battery cap and place them in a temporary container, so you don’t lose them. If it’s a sealed battery, use the flathead screwdriver to pry off the battery cover and battery cell caps underneath.
Carefully empty the battery acid from each cell into the bucket.
Add around 500gm of baking soda to the bucket to neutralize the battery acid, so it’s safe for disposal at a recycling center.
If there are any spills, pour the baking soda cleaning solution to neutralize this too.
Clean The Battery Cells
With a funnel, fill each battery cell with the cleaning solution. Replace the battery caps and shake the battery between 30 seconds to 1 minute.
Open the battery caps again and empty the cleaning solution into the bucket.
Replace The Battery Electrolyte
Dissolve 120gm of Epsom salt in 1 liter of distilled water (this creates an electrolyte of 1 molar concentration). You can warm up the water to help dissolve the Epsom salt. Mix it well until there aren’t any solids left.
Fill each battery cell and close the battery caps. Shake to distribute the salt evenly.
Recharge The Battery
Set the battery in a safe and secure area.
Remove the battery caps again as an additional precaution — the electrolyte solution will heat up and may overflow during charging.
Connect the battery charger to the battery terminal — the red wire to the positive terminal and black wire to the negative terminal.
Keep the charger as far away from the battery as possible, then set it to charge a very low current of 12V / 2 Amps. Charging at a low current allows the Epsom salt to break down the lead sulfate crystals on the battery plates.
Let the battery charger run for 24-36 hours.
Test Battery Voltage And Loading
Disconnect the battery charger and check the battery voltage with the voltmeter. The readings should be around 12.42V. If lower, reconnect the battery charger and charge up for another 12 hours.
If all is well, perform a rudimentary load test:
- Reinstall the battery, turn the ignition key to “ON,” and switch on the high beams
- Check the battery voltage again
Fixing a Bad or Dead Battery Cell in a Car Battery (Easy Steps)
Car batteries need to be replaced on a regular basis, right? Well yes and no. Healthy car batteries have a life expectancy of around 4-6 years. If you find your battery dying much sooner, it could be that there is something you aren’t doing right, this could be as simple as overcharging it.
Your battery is essential to the running of your vehicle and likewise, the cells are essential to your battery. So if you find that you have a faulty cell how do you go about changing a bad battery cell?
There is a quick and easy way to fix a bad or dead battery cell starting by mixing up Epsom salts and distilled water solution, using baking soda and water to remove any corrosion and dirt from your battery, opening the cells up, and emptying any remaining fluid, once this is done you can refill them with the Epsom salt solution and then recharge your battery. You should now be ready to get back on the road.
But first, what is a car battery cell and how do you go about fixing one? Well, keep reading to find out!
What Do I Do If My Car Battery Dies?
There are so many different things that could be causing your battery to die so don’t panic just yet.
The first thing to check is if your car battery is dead or if there is another reason that your car won’t start. Here are 8 signs that your car battery is dead.
- If you notice that your car is slower to start and it isn’t because the temperature has dropped. This could be a sign that your battery is on its way out.
- You’ve got headlights and power but still, the car won’t start. You may find that you get a click when you turn the key but the battery isn’t cranking to start the engine.
- Your radio doesn’t turn on don’t think this is a fault with your radio though. If your ignition is in the ON position the battery should normally run the radio as well as other electronic devices in your car.
- Check under your hood and if your battery appears swollen or a little on the chubby side you may have a fault with your alternator. This fault has caused your battery to become overcharged and is causing a buildup of hydrogen gas.
- You may notice an odd smell coming from your battery and this means it is reaching the end of its life if it hasn’t got there already. If the smell is a bit like rotten eggs you know this repair is going to cost you. The smell means that your battery has vented excess gas and also has probably released sulfuric acid in the process, which is going to cause damage to some other parts of your engine as well.
- Your battery may just be old. At the end of the day, the average life span of a car battery is between 4-6 years.
- The pesky check engine light is flashing or stays on constantly. This could be the start of some serious issues within your engine but you may get lucky with a quick car battery change.
- You may find that your battery actually has enough voltage to start the engine but it then immediately dies and isn’t able to idle at all. Now this fault could mean that there are any one of a hundred possible faults with your car and not necessarily a fault with your car battery.
So you’ve done your checks and it is definitely a faulty car battery, now it’s time for a replacement. It is recommended that you remove your old car battery as soon as you can as it can cause further damage to the vehicle.
How to Fix a Dead or Damaged Cell in a Car Battery
So if a dead battery cell is your problem then we have an easy solution for you. But first, you will need a few essentials to get that battery working again.
- Epsom salts
- Distilled water
- Baking soda
- Voltmeter
- Screwdriver
- Funnel
- Battery charger
Step-by-Step Guide:
- Create an Epsom salt mixture with half a quart of distilled water and eight ounces of Epsom salt. You will need to heat the mixture until the Epsom salt is completely dissolved and ensure that you are doing so in a well-ventilated area.
- Use baking soda and water to remove any corrosion from the battery. Corrosion on your battery can cause a wealth of issues.
- Use a voltmeter to check if the battery can be saved. Anything below 10v means a completely new battery is needed.
- Using a screwdriver, remove the top of the battery. This will expose the battery cells underneath. Remove the cell caps.
- Add baking soda to a bucket and empty the cell’s liquid. The baking soda will neutralize the cells.
- Use a funnel to refill all the cells, replace the cover and shake the battery for one minute.
- Recharge your battery starting at 12V/2 amps for 36 hours.
- Install the battery and test drive.
Here is a video to show you the step-by-step guide.
FAQs
What Happens If You Have a Dead Cell in Your Car Battery?
Dead cells in car batteries mean the battery itself cannot produce the amperage needed to start the vehicle.
Even if only one cell is dead, you will not be able to start your battery. This means either an entirely new battery is needed or you can refill the individual cells with an Epsom salt solution.
Can You Charge a Battery With a Dead Cell?
Batteries with dead cells cannot be charged or jump-started as they will not hold a charge. The singular dead cell will more often than not drain the cells around it leaving you with a completely useless battery.
Can You Fix a Shorted Battery Cell in a Car Battery?
Shorts are often caused by a manufacturing error and therefore cannot be repaired. A full replacement is your best option.
Can You Use Vinegar to Clean a Car Battery?
Yes, vinegar can be used to clean a car battery. Simply mix vinegar with baking soda and let it sit and fizz.
After a few minutes, you can use the mixture to remove any corrosion from the outside of the battery. Use water to rinse and leave to dry completely.
How Do You Revive a Car Battery That Won’t Hold a Charge?
Test every cell in the battery using a voltmeter. If any have a reading lower than 2 volts then top up with fluid and charge for 24 hours.
Here’s How to Start a Car With a Dead Battery Without Another Car
Push-Starting
Push-starting, also known as pop- and/or bump-starting, is a method of resurrection by which the engine is spun to life by force instead of a battery-powered starter. You’ll need a short, flat distance of street or a slight incline and a strapping friend or two to do the pushing.
- Direct your friends to the rear of the car and have them get ready to push.
- Hop into the driver’s seat and turn the ignition to “on.”
- With the parking brake still engaged, push the clutch in and shift to second gear. First gear isn’t recommended as it may cause the car to buck harshly.
- Press the brake pedal and release the parking brake.
- Release the brake and have your friends start pushing.
- At around 5 mph, release the clutch abruptly. The engine may sputter or buck slightly as the engine engages.
- If the engine starts, you’re all done!
- If it doesn’t, repeat the process at a higher speed.
- If it still doesn’t start, your problem isn’t the vehicle’s battery.
Utilizing a Jump-Start Box
Jump boxes are essentially small portable batteries with jumper cables attached. They also use software to prevent voltage spikes that can damage your car’s electrical system, so they’re safer than jumper cables. Some come with onboard safety lights, AC outlets, and USB ports to charge your phone. They’re also inexpensive and available at hardware, auto parts, and online stores. For all they can do, it’s worth getting one to keep in the car in case of emergencies.
- Make sure your jump-starter is fully charged.
- If not, plug it in and charge as directed.
- Most new jump-starters come with integrated cables, but if not, connect your own cables to the proper (positive and negative) posts on the jump starter.
- Connect the red clamp to the positive post ( symbol or red cover) of the dead battery.
- Connect the black clamp to an unpainted, grounded metal surface somewhere on the vehicle’s frame.
- Once everything is connected, turn the jump-starter on as directed.
- After a minute or two, start the car.
- If the engine doesn’t start, let sit for a few minutes to give the battery time to charge and try again.
- The car started? Fantastic.
- Turn off the jump-starter’s power switch.
- Remove the clamps in reverse order; black clamp from the grounded surface, red clamp from the dead battery.
- It’s a good idea to recharge the jump-starter after every start.
- You’re done, congrats!
Call For Roadside Assistance
Roadside assistance is often built into your car or motorcycle’s insurance plan, although you’ll have to check your specific coverage—roadside assistance phone numbers are usually printed on your insurance card.
Local towing services will have jump-starters for dead-battery situations.
- Find the tow service’s number either on your insurance card or with your phone. AAA Roadside Assistance
- Call that number.
- Wait for roadside assistance.
- Prepare small talk for your meeting with the service tech, (e.g. the weather, your favorite sports team’s victory, why you deserve that raise, etc.)
- Find a crisp 5 bill, or even a crumpled one, for a tip to show your appreciation. Always keep a few fives on you, grampa always said.
- They’ve arrived? Huzzah, you’re done!
Safety Third!
These methods are only to be used when you’re in mortal danger, and it’s riskier to not start your car than try these, (e.g. evacuating a war zone, running from zombies, if you’re terrified of small birds and there’s a flock of parakeets descending upon you, Seinfeld announced a one-time-only cast reunion and it starts in twenty minutes, or if The Drive’s Mike Spinelli has decided to streak down 5th Ave and you, unfortunately, have a front-row seat.)
(We’re sorry for that last visual—Ed.)
The MacGyver
- If you have a spare 12V battery from your portable drill, you can, carefully, tape two large screws to the battery’s terminals and then attach jumper cables to the drill’s battery and then the car.
- Don’t do this.
The Shocker
The Mike Tyson
Video
Yeah. There’s a lot to think about after all of that. Mostly how not to fry yourself. That’s actually easier to avoid than you might think. Just watch the clip below to see how simple it really is to jump a dead battery without cables.
Sign Up For Our Newsletters
The chronicle of car culture, delivered to your inbox.
© 2023 Recurrent Ventures. All Rights Reserved.
Articles may contain affiliate links which enable us to share in the revenue of any purchases made.
Extra Power Tips for Reviving a Dead Battery
Check the owner’s manual to be sure your car’s circuitry system can handle a jump-start. Don’t jump-start a dead battery if either car has an electronic ignition system. Never let jumper cable clips touch each other during the process. Never try to jump a leaking, cracked, or corroded battery. Don’t try to jump-start a frozen battery, as the process could make it explode.
If just can’t seem to revive your dead car batter, you can count on us here at Kennedy Transmission in Minneapolis, MN. Our master auto technicians work on battery, starting, and charging systems every day. Give us a call or schedule an appointment. We’re always at your service with seven convenient locations and the best auto mechanics in the state.