Marking the Battery
You should have a set of stencil letters and mark every battery you rebuild or repair. Stamp “POS,” “P,” or “+” on positive terminal and “NEG,” “N,” or on negative terminal. Then stamp your initials, the date that you finished rebuilding the battery, and the date that battery left the factory, on the top of the connectors. Record the factory date, and type of battery in a book, also your date mark and what was done to the battery. By doing this, you will always be able to settle disputes that may arise, as you will know when you repaired the battery, and what was done.
To go one step farther, keep a record of condition of plates, and number of new plates, if you have used any. Grade the plates in three divisions, good, medium and doubtful. The “doubtful” division will grow smaller as you become experienced and learn by their appearance the ones to be discarded and not used in a rebuilt battery. There is no question that even the most experienced man will occasionally make a mistake in judgment, as there is no way of knowing what a battery has been subjected to during its life before it is brought to you.