How is a battery constructed and what makes it work?
Lead Acid Batteries have been around for a long time, the technology is old but still very effective and affordable. Batteries will store energy and make it available to you when needed. This energy however, has to be replenished and maintained or it will dissipate and your car will not start as well as shortening your batteries life by a considerable amount. New cars increase the toll on batteries, with the stereos, alarms, electronic gadgets, etc. Understanding what's inside will make things a little clearer as to how to help them live a long time.
What is inside of a battery and what types of batteries are there?
If you were to open up a Lead Acid battery you would find a large amount of lead plates (and other materials). These plates are divided in cells, for a 12 volt battery you will find 6 cells. Each cell produces approximately 2 volts and are connected together in series, so
2 x 6 = 12. These plates and cells are surrounded by a bath of sulfuric acid and water. This solution is called the electrolyte and on some batteries you can actually remove the cover and see the liquid. Newer maintenance free batteries do not allow inspection of the liquid. This electrolyte causes a chemical reaction which produces electrons and that is what makes the battery work. (Ok... this is a very simplified answer but actual details would be a book all to itself).
There are a variety of Lead Acid designs that differ a little, they include Wet Cell, Gel Cell, and Absorbed Glass Mat (AGM). All of these technologies are similar but offer additional features and benefits. The most common is the generic Lead Acid which is offered in two forms.
The first is known as a Cranking Battery and the second is a Deep Cycle Battery. Basically the Cranking Battery is used in most vehicles and is designed to provide a large amount of energy for starting and are usually designed with more plates. Deep Cycle batteries do not provide this high energy level but rather they are designed for long term energy needs and can live with being deeply discharged and recharged many times. This type of battery is found in RV's, Boats, Golf Carts, etc. where a smaller extended load is being used.
A fully charged battery that is checked with our tester should read 12.6 to 12.9 volts. It should also be noted that there is very little difference in voltage between a fully charged battery and a dead battery which is about 11 volts. It is also important to note that a battery that goes below 12.4 volts is already starting the sulfation process and its performance and longevity will begin to deteriorate. That's why its so important to keep a charger connected when not in use... to keep this from happening.
What are the battery ratings and energy scales?
Batteries are rated by the amount of energy they can hold and their ability to produce current at a determined rate. The four ratings are AH, RC, CA, and CCA.
- AH... stands for Amp Hour and represents how many amps can be removed from the battery in how many hours. In other words a 20 AH battery on a motorcycle will provide 1 amp of power for 20 hours. The larger the AH the larger and higher the capacity of the battery.
- RC... stands for Reserve Capacity and isn't as commonly used as AH. It is the amount of minutes a battery will last with a 25 amp load and not go below 10.5 volts (fully discharged).
- CA... stands for Cranking Amps, this is rated measured at 32º F. It is the number of amps that can be delivered for 30 seconds while the battery stays above 7 volts. It's an indication of what a battery can put out quickly when trying to start a vehicle.
- CCA... stands for Cold Cranking Amps, and is similar to CA but at a lower temperature. The rating is done a 0º F, for 30 seconds and again until the battery gets to 7 volts.
Factors that negatively affect battery life are listed below.
Preventing these from happening will ensure additional longevity to your battery.
- Don't leave a battery uncharged for extended periods of time.
- Never add tap water to a battery use distilled water only.
- Try and keep stored batteries below 110º F.
- Don't overcharge or undercharge a battery.
- Never short the battery lead together... very dangerous, possible explosion.
- Keep the battery terminals clean and tight so that current flows properly.
- When working with batteries remove jewelry, have good ventilation, remember that sulfuric acid is very dangerous, keep off skin and away from eyes.