How to Revive Sealed Lead Acid Batteries

You might think these things are just pieces of junk in your garage, but if you learn how to revive dead batteries, you can actually use them again! The only reason you're not using a dead car battery is due to its inability to provide the amperage to start a car. Still, even if they can't help your car, the truth is, they're still useful for other pieces of equipment. But first, you need to know how to rejuvenate a lead-acid battery.

Revive Dead Batteries | Restore Sealed Lead Acid Battery

What You Will Need:

  • Dry Cloth
  • Razor
  • Flat-Head Screwdriver
  • Water
  • Battery Charger
  • Meat Syringe (Optional)
  • Multimeter

Let's get to work!

Step 1: Clean the Battery

Clean the Battery | How to Revive Sealed Lead Acid Batteries
You've probably heard of using Epsom salt to revive dead batteries, but that has not worked for everyone. This guide will take an alternate route and see if this one works for you. The first step in how to fix a dead car battery is to clean up the outer casing. Spray some biodiesel, olive oil, or kerosene, then wipe it with a dry cloth. You can skip the cleaning if you want, but it's always good to start working without the mess.

Step 2: Remove the Top Cover

Remove the Top Cover | How to Revive Sealed Lead Acid Batteries
Go around the edge of the top cover using a razor blade to the point of being able to detach it. You can also use the razor to lift the cover. Please be extra careful when holding the razor. As soon as you see a lift, slowly switch to a screwdriver. Gently raise the top by working the screwdriver under the case.

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Step 3: Fill the Cells with Water

Fill the Cells with Water | How to Revive Sealed Lead Acid Batteries
Take the caps off so you can fill each cell with water. You can use a meat syringe to fill a single cell with 20 to 30 milliliters of water. A dry battery usually takes one full syringe, but it's okay to use any method you're comfortable with, as long as you completely fill each cell.

Step 4: Start Charging the Battery

Start Charging the Battery | How to Revive Sealed Lead Acid Batteries
You can start charging the battery now. This demonstration makes use of Da Pimp charger, which is also a portable battery tester. Place the leads for the DC side correctly on the battery. It's as easy as “black to black” and “red to red.”

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Step 5: Leave the Battery Charged for 15 to 20 Minutes

Leave the Battery Charged for 15 to 20 Minutes | How to Revive Sealed Lead Acid Batteries
You may see a really bad voltage reading before you start charging the battery. Let the charger work on the battery for 15 to 20 minutes, then check the voltage reading again. If the reading shows pulsing signs, try to give it 15 minutes more until the voltage reading stabilizes.

Step 6: Check the Voltage Reading of Each Cell

Check the Voltage Reading of Each Cell | How to Revive Sealed Lead Acid Batteries
Now, you can turn off the charger and check the voltage reading of each cell. At this point, you will know if any of the cells are dead or weaker than the others. With the use of a multimeter, set it to voltage DC with the positive probe on the positive terminal of the battery and dip the negative into the acid for each cell. You'll get different readings, but it will let you know if any of the cells are dead.
That's just about all that's needed to be done for a sealed lead acid battery recovery. Easy work for anyone!

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Here's the full video by The Good Life Lab on recovering an old sealed lead acid battery:

Isn't finding a good use for things sitting at the corner of your garage neat? Reviving dead batteries is a handy skill to learn. Furthermore, it won't take much of your time to recover an old lead-acid battery. Try using them in your house for small, low voltage devices. For example, you can use them to power a small fan, a desk lamp, or even for emergency lighting. You can use the battery as a power source for a lighting system in your house, or use it for whichever device you please.

Have you tried to revive dead batteries? Share your experiences in the comments section below!

Up Next: Bring Dead Ni-Cad Batteries Back To Life | Prepper Skills

Editor's Note: This article was first published in November 2017 and has been updated for quality and relevancy. 

16 Responses to :
How to Revive Sealed Lead Acid Batteries

  1. Wilma says:

    Survival seems to be the thoughts of the day and I appreciate any of these tips I can use to survive. I’ve thinking of solar panels to offset the price of fuel to heat my house. If you have any ideas on how-to-do such a project I’d appreciate that too.

    1. Afungi says:

      The problem is the cost trade off is awful. 70 watts will cost about $700.00 and will give you the heat equivalent of a single light bulb. Putting a tremble wall on a south facing wall give you the best bang for the buck. A Nova Scotia man used aluminum cans and insulated box below south facing windows to collect heat small fan to move air. An Idea I have is to put heat ducting in the addict space with a thermostat controlled fan. The air in the addict can get very hot even in the winter. When the air gets over 100 deg. the fan moves air into living space. The problem is getting a good louvered shut off for the ducting.

      1. Lux17 says:

        Here is an 80 watt panel for $149.
        I got my 80 watt panel used for $100

    2. tj mac says:

      We had made a solar water heater for a small cabin… not expensive for heat output.
      4×8 plywood, 2×4 to frame plywood, clear heavy plastic/plexiglass and copper pipe (you can use plastic pipe too for slight less heat vs cost )and the most costly part was a small electric pump (slow flow which we got used for $20,allows water to pick up heat as passes thru) Total cost was $50-60 as we used what we had. PS some auto antifreeze too
      Frame plywood with 2x4s, cut additional for two(short side of plywood) cross pieces inside of frame. Drill holes thru center of cross pieces for size of pipe used, about 1/2 – 1 inch space between holes…cut cross piece in half so you have sort of ‘stock-pillory’.
      Put pipe into notches across the length of plywood, put second half on top to hold pipes(screw in place). Connect each end of pipe to one below…( big “s” snake back and forth,top to bottom) spray all with flat black paint, then cover plywood with heavy clear plastic over outer frame.
      We placed it on the south roof and ran it with pvc into a salvaged hw base board heater of 10 ft… when running during day the water output from solar panel was over 130d… gave out good heat during day ( had to run the stove at night ) Worked so well, we added a second one in series with a second section of base board… we wired a thermostat to the switch for the pump later too. Prob savings were about 30% in heating.
      Hardest part was purging air during install, had one person on roof fill system to eliminate air bubble… prob easier to add some form of air purge valve at high point of system if I was to re-do(right off panel).

  2. Lux17 says:

    Hello Wilma,
    I am planning on doing some testing with a 12 volt water heater element this winter. There is a company called SJH that makes among other things, 12 volt submersible water heater elements (for the RV industry). I am not sure if this is the best way to go, but for camping at home it is cheap and very scaled down. I forget all the wattage SJH makes but I know for sure that they make 300 and 600 watt elements. In a survival situation where people are stuck at home with no power and sub zero temperatures, the element is in a tank or large bucket of water. The water is heated all day and is radiating heat into the room or better yet into the tent in the room. Large amounts of water retain heat well, so if you were to heat up a 50 gallon drum of water during the day it would radiate some heat all night. This sort of thing could be scaled up for your application. This is not the only way to produce heat with solar panels. You can go the more traditional route and get enough panels for one 120 volt off grid circuit (and the batteries and inverter to go with them) and run an electric heater. Hopefully some others have some ideas. Here is one place to get an sjh heater:
    Typically submersible heaters have to be in water or they burn out. They need the water to dissipate the heat.

  3. Chuck says:

    Water left in a black plastic bag in the sun will get quite hot. Not hot enough to sterilize anything, but certainly hot enough to wash with. Try to spread the bag out so that more of it is exposed to the sun. This will even work on a cloudy day. Same principle as solar water heaters only on a smaller, less expensive scale.

    1. Chris Crow says:

      I have purchase the solar shower bags and do use those but also I use gallon milk jugs that are spray painted flat black and set them in the sun. It’s easy to take a shower with just one gallon of water. Also great for dishwashing. They are dirt cheap to make. And yes, sometimes the water is almost TOO hot to handle 🙂

  4. Satchmo says:

    I saw you can also make fire with a AA battery too. It’s always a good idea to keep a stash of batteries for the BOB. They have some over at for pretty cheap.

  5. Curious 1 says:

    It is my understanding that you can harm your battery by using tap water to fill the cells. Distilled water is recommended.

    1. prsmith says:

      A water/alcohol distiller will be priceless in a grid-down situation.

  6. Bill Croy says:

    Just be aware that most batteries stop holding a charge because they have been charged and discharged in the wrong manner. Most batteries will form sulfates on the internal plates when used in a wrong duty cycle and are only good for paper weights or boat anchors. If a lead acid battery is left in a discharged condition for long it will sulfate beyond use. Whether it is a “Gel-cell” “Sealed Liquid Cell” or the general “Flooded Cell”. This is true for VRLA, AGM, Engine starting (Cold Cranking Amp) and Deep Cycle battery types. The wet cell Nickle Cadmium and Silver Cadmium batteries have their own special handling use problems. If you are going to refurbish batteries or plan to have a battery backup system, do your research and do it safely.

  7. What kind of charger are you using?

  8. Aussie C-B says:

    Finally I didn’t have to listen to some moron telling me how when he was in the Special Forces on patrol how they used to carry 300kg betteries for 37km while being shot at by gun ships in a swamp on the edge of a cliff at night and transfer to acid from one battery to another using only a condom and a broken radio antenna.
    This was a simple easy to follow process that anyone can try.
    If the battery isnt to far gone you could get it working, but if not you only lost a bit of time for the attempt. The only thing to lose if you try to fix anything that’s broken is time, if it doesn’t work and you try to fix it and it still doesnt work you can be sure you have at least learnt something on the way, If you do fix it then well done you!
    There are too many people ready to have a crack at everybody’s ideas out there without contributing anything except their own obvious insecurities.
    Great tutorial – there’s two batteries in my garage that are getting a tickle tonight.

    1. Aussie C-B says:

      UPDATE ……..I tried both batteries and both were beyond saving. Bill Croy was right, when i took them apart the plates inside were just solid black lumps.

  9. I never knew that some people can use Epsom salt to revive dead batteries. We have some Trojan batteries that have died. Thank you for the tips on reviving a dead battery.

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