Opening a Car Battery and Repairing (Auto Interior Repair). The first thing to do is to take the top or lid off the battery. It will have vents or cavities for holding acid content. These holes can be accessed on the outside top of the car battery itself or inside, depending on the brand or battery type.
- Your aim is to render a car battery functional again using the potent properties of Epsom salts in solution.
- The vents inside will most probably be dry with only a few of them half full. Fill these up half way with some distilled water in preparation for the next step.
- Set your battery charger accordingly and charge at 1 amp. This will take time and you need to be patient.
- Take some epsom salts and add them to each of the vent holes in the battery. Gently shake the battery, taking every safety precaution you need to. This step will be relatively simple if the battery has a handle that you can use while gently rocking it so the epsom salts mix thoroughly.
- After a couple of hours or so, add three spoons of Epsom salts to each cell. Use a common plastic funnel to help get the powder in evenly without spilling.
- The voltage will have improved from last time. The process is not done yet. Charge for a while longer, and use a thin water spray to clean up any excess salt remainders around the vent cavities. It is alright if they stream into the vents.
- Put the lid loosely back on or the vent caps, whatever the case. With 2-3 days of light charging on and off, you may see around 11.5 volts (preferably more) showing on the voltmeter. This is not great, especially if yours is an old battery you are looking to recondition, but it will do.
- Take a pair of pliers and perform a spark test. Hold the pliers safely at the plastic grip and touch the metal head to one of the nodes or battery terminals. If you see sparks, the battery holds voltage.
A new battery or relatively functional one will be better than anything old and long-used, so make sure you do not use a bad battery in your car unless you know what you are doing.