Lead Acid to Alkaline Battery Conversions

While I was searching for information on Nickel Iron batteries aka Edison Cells I stumbled upon something that is a complete gamechanger for diy backwoods low budget alternative energy.
You can take a heavily sulphated lead acid battery that still comes up to voltage but has little amperage output, switch out the electrolyte and you wind up with a nearly completely restored battery. Apparently the voltage winds up slightly lower, but the amps output is largely restored.


Take into account when handling lead acid batteries that they are both toxic and corrosive, thus pose many environmental and health risks. Wear appropriate PPE, work in a well ventilated area and dispose of any waste materials in a responsible manner. Even with appropriate precautions bad things can happen, so attempt this at your own risk. I should be able to go without mentioning this, but then again this is the internet and you may be Smart Like Truck.


From the reading I’ve done so far there are several different electrolyte conversions that have been tested.

  • Magnesium Sulphate – common epsom salt
  • Aluminum Sulphate – common pickling alum
  • Copper II Sulphate – cattle footwash
  • Successful conversions seem generally to have 4 to 8 ounces of sulphate mixed with 1 gallon of water for electrolyte.

    Battery Selection

    The ideal battery needs to be in relatively good physical condition with little damage to the plates and low sediment in the cells. An easy way to determine if a battery will make a good candidate is if it is able to be charged to over 12 volts and hold that state over an extended time. The battery I’ve chosen for my first conversion currently holds over 12.5 volts and has done so for months, but this number dives when a load is applied with my load tester. A peek inside the cells shows water clear electrolyte and light colored plates. The battery also shows no external signs of damage such as swollen sides which would indicate the battery was frozen and thus the plates physically damaged. Extreme sediment of the cells can cause shorting and will show a low voltage even after a full charge.

    Cell Cleaning

    It seems the consensus among experienced battery converters is to do very little in the way of flushing or cleaning of the battery cells, dump out the electrolyte and pour in new electrolyte, this of course is for the ideal candidate battery. For less than ideal batteries you may increase your chances of success by flushing the cells several times with water, or in extreme situations flushing with a sodium bicarbonate (baking soda) solution then several washes of clean water.

    Charging and Cycling

    After you have replaced the electrolyte an initial test of the battery may not show the battery’s full potential. By discharging and recharging the battery (cycling) you further the conversion and condition the battery.


    Here are some links to some battery conversion pages out there


    I’ll update this story as I learn more and  links to results of my own experiments.


    1. Hi, I have 16 alum battery some from older batties and some are brand new. I use them to power the house. they charge up to 13.6 and drop down to 11.8 at night, but dont drop below that.They work vary well.

      • Hi Rex,

        Sorry, I haven’t sorted my comments folder for a long time.

        That’s awesome that you are actively using converted batteries for your power system.
        Have you shown any of the details of your system on a blog or forum somewhere?
        I’m definitely interested in seeing what you’ve done.