In this video I show how to repair a 12 volt car battery for under 5 dollars using food grade Alum “Aluminum Sulfate” and baking soda. A shortened version of this video can be seen at https://youtu.be/boHdHcIWhEM. First I use baking soda to clean the battery and then Alum instead of a acid to bring it back to life. The best price I have found for alum is here https://amzn.to/2LBzZ61 which is enough to do several batteries. Your local feed mills or grocers may carry it as well.
Part 1 converting the battery from acid to alum
Part 2 testing the battery again more extensively almost 6 months later http://www.youtube.com/watch?v=5YeRe1fwNYc&feature=youtu.be
Started a drain over time test you can view the first 16 days results here https://www.youtube.com/watch?v=TBx4U74suwI
3 months drain with no charge started truck 4 times including the last starting the truck in 10 degree F
1 cup or 8 oz of food grade alum “aluminum sulfate” in a 1 gallon jug then fill the jug with water “it is best to use distilled water”
Same for the baking soda 1 cup per gallon. The baking soda mix is used after draining the acid to neutralize any left over acid. You can then after rinsing with that rinse with plain water to get out the baking soda mix. Then you will put in the alum mix filling to just above the plates and then charge.