Handy Battery Facts And Information
October 26, 2002

compiled from various Internet sources

Battery Basics:
A battery is a device that converts chemical energy into electrical energy.  A dry-cell flashlight battery consists of an electric cell, but larger batteries are made up of a group of cells that are connected to act as a source of direct electric current at a given voltage.  A cell consists of two dissimilar substances - a positive electrode and a negative electrode - and a third substance, an electrolyte that acts chemically on the electrodes.  A group of several such cells connected together is called a battery.  Batteries are widely used as a source of direct current electrical energy in automobiles, boats, aircraft, portable electric and electronic equipment, and lightning.  A car battery is used mainly to start the motor. Once the motor is running, an alternator supplies current to power accessories recharge the battery.

What is a "Gel Cell"
A technique for sealed lead-acid batteries. The electrolyte solution is in a gel form, usually silica gel, instead of plain liquid.  A gel cell is a lead-acid electric storage battery that:

- is pressurized and sealed using special valves, and therefore should never be opened.
- is completely maintenance-free.
- uses a thixotropic gelled electrolyte.
- uses the "recombination" of Hydrogen and Oxygen as described below.
- is non-spillable, and therefore can be operated in virtually any position. However, installation upside-down is not recommended.

Connections should be re-torqued and the battery cleaned periodically

How does a gel cell work?
A gel cell is a "recombinant" battery. This means that the oxygen (O) that is normally produced on the positive plate in all lead-acid batteries recombines with the hydrogen (H) given off by the negative plate. The "recombination" of hydrogen and oxygen produces water (H2O) which replaces the moisture in the battery. Therefore, the battery is maintenance free, as it never needs watering.

The oxygen is trapped in the cell by special pressurized sealing vents. It travels to the negative plate through tiny fissures or cracks in the gelled electrolyte. The sealing vent is critical to the performance of the gel cell. The cell must maintain a positive internal pressure. Otherwise the recombination of the gasses will not take place, and the cell will dry out and not perform.  In addition, the valve must safely release any excess pressure that may be produced during overcharging. Otherwise the cell would be irreparably damaged.  It's important to note that a gel cell must never be opened once it leaves the factory. If opened, the cell loses its pressure, and the outside air will "poison" the plates and cause an imbalance that destroys the recombination chemistry.  Hence the name: Sealed Valve Regulated (SVR) Battery.

What is the difference between gel cell and "starved electrolyte" batteries?

Both are recombinant batteries; both are sealed valve regulated.  The major difference is that the "starved" or "absorbed electrolyte" battery contains an amount of liquid electrolyte added at the factory that soaks into the special separators. Therefore, it is non-spillable because all the liquid electrolyte is trapped in the sponge-like separator material. There is no "free" electrolyte to spill if tipped or punctured.  Because of this "acid-starved" condition, this type of battery does not normally perform  well in heavy, deep discharge applications. The gel cell has more electrolyte available,  therefore it is better suited for deep discharge applications and can accept occasional overcharging.

Some Handy Terms:
Cold Cranking Amps:  is a rating used in the battery industry to define a battery's ability to start an engine in cold temperatures. The rating is the number of amps a new, fully charged battery can deliver at 0° Fahrenheit for 30 seconds, while maintaining a voltage of at least 7.2 volts, for a 12 volt battery. The higher the CCA rating, the greater the starting power of the battery.

MCA or CA rate:  This is a rating used to describe the discharge load in amperes which a new, fully charged battery at 32 degrees F (0C), can continuously deliver for 30 seconds and maintain a terminal voltage equal or greater than 1.2 volts per cell. It is sometimes referred to as Marine Cranking Amps or Cranking Amps.

Reserve Capacity (RC): is a very important rating. This is the number of minutes a fully charged battery at 80 degrees F will discharge 25 amps until the battery drops below 10.5 volts.

Amp hours (AH): is a rating usually found on deep cycle batteries. If a battery is rated at 100 amp hours it should deliver 5 amps for 20 hours, 20 amps for 5 hours, etc.
 
Math:
The formula for determining battery energy is:
     E = P·t = V·I·t
Where:

     I = Current Expressed in amperes
     V = Electromotive force expressed in volts
     P = Power expressed in watts
     t = Time expressed in hours
     E = Energy in joule

More:
Battery manufacturers, distributors, or large chain stores will often private label their batteries, for example, EverStart for Wal-Mart, DieHard for Sears and DuraLast for AutoZone. The larger chain stores might have batteries with their private label made by several manufacturers depending on the location to reduce shipping costs.  Below is a list in alphabetical order of the largest battery manufacturers, joint ventures, or distributors and some of their brand names, trademarks and private labels. Ownership, supply contracts, branding, web addresses and telephone numbers are subject to change.  For example, Exide recently purchased GNB and Johnson Controls purchased Optima.

The manufacturer's code number will be on the battery and is only sure way of identifying the manufacturer. Ask the dealer who made the battery. Manufacturers, joint ventures or distributors will sometimes have lines within a trademark of brand, for example, Bronze, Gold, Silver, Premium, Heavy Duty, Commercial, Standard, Plus, Turbo, Calcium, Classic, Maintenance Free, etc., for differentiating quality, features or warranty periods. They will also contract with other manufacturers to build special purpose batteries. Trademarks, Brand names and registrations are owned by their respective companies and are as shown HERE

Here's some handy links for further reading:

Please contact the webmaster if you spot errors or omitions in this article