Welcome to Battery Reconditioning. Here we will show you how to recondition batteries with step by step guides. Battery Reconditioning is a simple skill that everyone can learn, It doesn’t matter if you know nothing at all about batteries.
You can be sure that you’ll be able to recondition your Battery today with little required equipment and materials. I’m going to show you how to recondition a standard 12v car battery. Stay tuned for other battery reconditioning guides which you can try later. I’ll list them at the bottom of this page.
The 12v car battery is most common battery that people want to recondition and for obvious reasons, your car is important and a new battery for it is expensive . By reconditioning your car battery, you can save yourself a bundle and also help the environment by basically recycling or refurbishing your battery.
Warning: The liquid (Electrolyte) in lead acid battery cells is very dangerous. It’s a mix of sulphuric acid and water. You don’t want to get it on your skin, in your eyes or even on your clothes. So be extra careful, I will provide additional safety advice step by step below.
Safety Tip 1! Make sure you are wearing your safety goggles and gloves from start to finish.
The first stage of battery reconditioning is to clean the battery posts (terminals). There will be corrosion built up on the battery posts. I recommend using battery post cleaner* for this but it’s optional, you can create your own solution and use other brushes to get the same results.
Cleaning Battery Posts With Steel Wool
To create your own battery post cleaning solution, you will need a tablespoon of water and 2 table spoons of baking soda, Mix the two together until you have a runny paste. Then take a toothbrush and apply it to your battery posts. Whilst scrubbing the battery posts you should notice the solution foaming up. This means that your solution is reacting to and removing the corrosion from the battery post.
If your battery has a heavy corrosion on the terminals you may need swap out your brush for steel wool or a steel wired brush. You can also use 300 grain sandpaper.
Now you will want to clean the outside of your battery with water mixed with baking soda and an old rag. Wipe down the top of the battery around the posts and caps.
After you have cleaned the battery and terminals it’s time to test the current voltage of the battery and move on to battery reconditioning.
To check the voltage of the battery you’ll need your voltmeter these common testers and cheap to buy. Take your voltmeter and connect it to the battery terminals. Make sure you connect the voltmeter correctly and you should see what condition your battery is in. If you see 12.6v+ then your battery is in good condition and the corrosion on your posts may have been causing issues. Don’t see 12.4v or more then your battery needs reconditioning. Also if you see 0 volts then it’s likely that your battery has suffered a short circuit and this battery reconditioning method likely wont fix that.
After you have your voltage reading you’ll know whether you need to proceed with Battery reconditioning or not. You should write down the voltage reading for future reference when testing your battery after reconditioning.
Safety Tip 2! Battery acid is very dangerous so make sure you are wearing your goggles, gloves and apron. Do this in a well-ventilated area!
Now it’s time to remove the old acid that’s left inside your battery cells and then clean the inside of the cells. Take your flathead screw driver and slide it under the battery caps. Commonly you’ll have 2 or 3 caps but sometimes you can have 6. Once all the caps are removed you want to make sure you have your bucket ready to pull the acid into. You’ll also want to make sure that you have some baking soda nearby so if you spill the acid you can neutralize it with the baking soda.
Take your battery and lean it away from yourself into the bucket. Take your time and try not to spill any of the battery acid as you roll the battery over until it is upside down above the bucket. When the battery cells are all empty place your battery to one side and take ½ lb of your baking soda and add it to your bucket of old battery acid. This will neutralize the battery acid so you can safely dispose of it later.
Now it’s time to clean the inside of your battery cells. To do this you need to mix ½ gallon of distilled water with ½lb of baking soda. Once mixed use your funnel and pour your baking soda mixture into each cell of the battery until each cell is full. Clip the battery caps back on and shake your battery around for a good 30 seconds to a minute. Now remove the battery caps again and empty your battery cells into the bucket of battery acid and baking soda. You should now have an empty battery that’s clean and ready for battery reconditioning.
Now you have your old car 12v battery 100% clean and empty you can now refill cells. We are going to refill the battery cells with a new electrolyte made from distilled water and Epsom salt . This is to raise the voltage and increase the amps the battery can give. Also this will stop the sulphating on your plates that is killing your battery and allow you to charge and use the battery again.
Take ½ lb Epsom salt and ½ gallon of distilled boiling water. The reason why you want to boil your distilled water is to make it easier for the Epsom salt to dissolve. Add your Epsom salt bit by bit whilst stirring it into the distilled water. What you are looking for is clear water, then you know the Epsom salt as fully dissolved. And you have your battery reconditioning electrolyte ready to go.
Once all the Epsom salt has been added and is fully dissolved in your distilled water you have your electrolyte and can begin to refill your battery cells. Take your funnel and start filling each cell until you hit the fill level. You want to make sure each cell is 100% full. If not then make more electrolyte although you should have plenty enough (any extra leftover electrolyte keep to one side for later on). Once all the cells are full of your new electrolyte the battery is nearly reconditioned. Now you need to put your cell caps back on and shake the battery around for a minute or two. Then take the cell caps back off and all that remains is to charge it. And if required cycle it a few times to improve the amp output.
Safety Tip 3! Do not put the caps that cover your battery cells back on whilst charging it, it’s likely that the electrolyte liquid may heat up and overflow. You don’t want pressure building inside the cells.
So now it’s time to give our reconditioned battery its first charge so grab your battery charger and put it as far away from your battery as the leads will allow. Make sure the charger is unplugged whilst you connect it to avoid any sparks.
Connect the positive lead (+ red cable) to the positive + battery terminal then connect negative (- black cable) to the negative terminal. Now you want to put it on a slow charge 12v/2amp is the best then leave it to charge for at least 24 hours, 36 hours is optimal. When the time has passed it’s time to load test your reconditioned battery. Unplug your battery charger before you disconnect your battery from the charger again this is to avoid any sparks.
You need to use the 2amp Trickle Charge Setting
Again, take another voltage reading with your voltmeter and write down the result. If you are seeing more than 12.43v then that’s good and you can proceed to a load test. If you haven’t got more than 12.43v yet don’t worry, if you had any electrolyte overflow whilst charging then you need to top the cells back up with more Epsom salt and distilled water then put the battery on charge for another 12 hours. Hopefully after this time you should now be seeing 12v+.
If you have a battery load tester then you can use that. And if you plan on reconditioning more batteries then I recommend you pick one up, you can buy a fairly cheap one from most hardware stores or from Amazon or eBay.
If you don’t own a battery load tester don’t worry because you can still test your newly reconditioned battery without one. You just can’t be exactly sure how many amps your battery has under load. But by using your voltmeter and putting the battery under load you can see how much voltage the battery has whilst under load.
Put your 12v battery back into your car and connect it again now you want to put on your high beams (do not start the car engine) the high beams will put your battery under load. Wait 5 minutes to remove any surplus charge. Then take a reading from your voltmeter, if it is reading more than 9.6v then the battery is in working order. Anything under 9.6v then the battery reconditioning process still needs some work.
If your reconditioned battery fails this first load test and is below 9.6v then you need to cycle it. Cycling a battery is basically discharging it (draining it) then charging it again, to speed this up you will want to put your battery under load for a time. So, turn on your high beams again and leave them on to start draining the battery. After some time, your lights will dim, you can now disconnect the battery and repeat the charging process.
Safety tip 4! Remember to remove the battery cell covers whilst charging your battery.
When your battery has had another 24-36 hours on a slow charge check your battery cells to make sure they are still full of electrolyte. If they aren’t top them up and take a voltage reading again. Write it down and proceed to do the load test again. This time you should be seeing over 9.6v whilst under load. If you aren’t then cycle the battery again. This may take up to 5 cycles but the vast majority of the time the battery will be reconditioned and over 9.6 volts after the first or second charge.
And that’s it you now have a working reconditioned 12v car battery, generally these batteries will last for another 12 months or sometimes more. After that time if the battery gives up you can try this battery reconditioning process again, I’ve managed to get it to work 3 times before the battery was finally dead.
There are a few alternatives to Epsom salt battery conversion. I personally stick with Epsom salt because I’ve had the best results from it. But you can still try battery reconditioning with alternates to Epsom salt.
One battery reconditioning substitute is Aluminium sulphate . After flushing the battery with baking soda like I mentioned above you can fill it with an electrolyte made from: Aluminium Sulphate plus distilled water. Instead of Epsom salt (Magnesium sulphate) and distilled water.
To do this you will want to mix 1 lb of Aluminium sulphate with 1 gallon of boiling distilled water. Mix the solution so it’s as clear as possible. Fill the cells with the solution and then charge the battery.
You’ll notice that the battery charges faster when the electrolyte is made from Aluminium sulphate. One extra point to note would be the condition of the battery you are reconditioning. If the battery is in fairly decent condition nearing the end of its life then Aluminium sulphate may be a good option but generally Epsom salt is better for batteries that are much more worn out.
People convert their lead acid batteries to Aluminium straight away. Doing this can increase the life of the battery because aluminium does not eat at the plates as fast as the normal electrolyte found in lead acid batteries. You can do this too with a brand new lead acid battery, Just follow the battery reconditioning steps above to replace your electrolyte.
Copper sulphate is another alternatives to Epsom salt for battery reconditioning. I’ve seen others use copper sulphate in battery reconditioning. If it works, its short lived and can do more damage than good to your battery. So with this in mind I highly recommend you avoid battery reconditioning with copper sulphate because it simply does not work effectively and Epsom salt is a far better choice for battery reconditioning.
Here are some other step by step battery reconditioning guides. You can follow these battery reconditioning guides to recondition other types of batteries.
If you found this guide or any of the ones above useful but are still struggling, Then I recommend you check out my Ez Battery Reconditioning review and consider taking the course.
Its a great course that will teach you everything there is to know about battery reconditioning. With pictures and email support from a dedicated teacher.
So now you know how to recondition car batteries. I’d like you to report back to me on your success or failures, and of course ask me any questions about battery reconditioning that you may have. I will try to answer as many as possible. You can do this by posting a comment down below. I look forward to reading them. Please if you found this helpful share it with your friends.
Great job, very thorough, gonna try it. Way to focus on safety. thank you. I am an auto shop teacher should be fun to try with my students. Think I’ll do one first.
Great information.. Thank you. I’ve heard about this process, but steps well detailed and clear. I’m going to give it a try! Thanks again!
Came across your website and decided to follow up on the directions. Have done 2 batteries so far with good results. Starting a third one today that shows 2.6 volts and won’t take a charge. It also had a dry cell. We will see how it goes. Thank you for a straight forward set of directions.
Once they are reconditioned do you have to empty out the Epsom salt solution and refill with an acid solution?
Nope no need for a new acid solution Wayne. Keep the Epsom salt solution in the reconditioned battery cells.
if you want battery reconditioning with epsom salt Download the complete guide here!