- 12-volt wet-cell battery is made up of six smaller 2-volt cells wired together inside. Each cell contains a lead plate and a lead dioxide plate separated by a sulfuric acid-distilled water solution. The battery case is made of a tough plastic. Two lead posts provide connection points on either the top or side of the battery. Removable caps allow access to inspect the battery water level.
- A properly charged car battery sends a stream of electrons from the negative terminal to the positive terminal, when the circuit is closed by a switch. The device in use draws the power needed and the battery begins to slowly lose charge when the engine is off. The rate of discharge depends on the amount of current drawn. A starter motor will probably leave a battery dead or very weak with less than one minute of cranking; while a car radio may keep the battery going all night without leaving it dead. The alternator sends current to replenish the battery charge on a continuous basis, so the battery remains near full charge while the engine is running.
- The sulfur in the acid gradually forms crystals on the lead plates, in a process known as sulfation. Battery life is shortened by excessive heat, vibration or severe use conditions -- such as frequent deep discharging. Lead powder eventually accumulates at the bottom, or the plate crystals grow large enough to short the cells. The battery cannot be repaired once this happens. If the water level in the battery gets too low, the tops of the cell plates become exposed. This will damage the cell and greatly shorten battery life, because it speeds up the sulfation process that destroys the plate surface. A battery that is not used for long periods of time will gradually sulfate; as sulfur in the acid deposits onto the battery plate.
- A number of battery repair liquids or powders marketed to reverse battery cell damage contain the chemical EDTA, and they may briefly resurrect a dead battery by removing some of the sulfate buildup. However, the underlying lead is diminished as well, so the battery won't last long after such a treatment, regardless of claims to the contrary. On the other hand, a battery conditioner is an effective way to keep an infrequently driven or stored vehicle's battery from discharging and sulfating. The device delivers a small, microprocessor-controlled charge to keep battery voltage stable. It may be able to reverse limited sulfation, but a shorted battery is too far gone for any remedy.
- Preventative maintenance on the battery is the only sure-fire way to prolong cell life. The water level should be checked regularly and replenished with distilled water only. Battery terminals should be periodically cleaned, tightened and sprayed with a battery terminal protector which reduces oxidation. The battery should be securely mounted in the vehicle to reduce movement and vibration, and the proper size battery must be used for the vehicle in question.
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