Acid for batteries is not a conventional acid to be taken lightly because it is, as a matter of fact, sulphuric acid which is a known strong acid and a hazardous chemical. This industrial chemical is found in lead-acid batteries as an electrolyte forming 35% of the solution.
Chemical manufacturers know the hazards of the chemical and many companies working with the acid apply safety measures and employ precautions. Workers exposed to it should know its hazards. Known for its caustic properties, it eats through fabric and reacts with organic compounds and burns tissue. The acid found in lead-acid batteries is diluted with water, but even so the liquid is still corrosive.
You can see a lot of people asking about Acidaburn acidifying their car batteries when the battery fluid level drops. Adding acid to such batteries is never advised for the drop of electrolyte level is most probably due to loss of water, in which case only addition of deionized water is the solution. Nonetheless, there are instances when adding electrolyte is necessary.
Loss of electrolyte may occur in cases of accidental spilling and leaking. Mishandling may be the most likely cause of spillage. If during maintenance check the battery is laid on an uneven surface and tips over, then the spilling of the acid solution results to the loss of electrolyte. Replenishing the acid may require adding the appropriate electrolyte solution which can be purchased from a battery acid supplier.
However, do not refill a leaking battery. Have it refurbished before refilling with acid. A lead-acid car battery that leaks sends corrosive acid out to destroy engine parts exposed.
There are reputable chemical companies that sell sulphuric acid for different purposes, one of which is for use in lead-acid batteries. But you cannot buy the chemical just like that. Be aware though that sulphuric acid may be found in many sources, but only use an acid solution that has the appropriate concentration. You have to ensure the right solution which should have the right acid-water proportion. You can ask the auto battery dealer for the specifications of the acid if you are unsure.
You can look online for suppliers of the chemical or you can drive to a near chemical shop to find out. One problem with purchasing the chemical online is that you may have to deal with shipment cost. The company may also have to deal with stringent government policies regarding shipment or transportation of the product. For hazardous chemicals such as sulphuric acid solution, there are specific guidelines.
Anyway, suppose you have the package in your hands. The next concern is your safety while you are working with the acid. Careless handling can cause serious injury. Some people are keen enough to wear safety gear such as goggles or face mask, hand gloves, boots, etc.