CMOS Batteries-Information | Tech Info Home Page |

General Information - 

If you are looking for CMOS batteries go to the "CMOS Batteries" page.

CMOS batteries come in several flavors. A non-rechargeable Lithium type, a non-rechargeable standard AA size battery pack ( 4 AA batteries) and varied rechargeable types such as NiCads. Additionally, the battery can be an internal rechargeable NiCad type that is soldered on the motherboard or a calculator/watch style (looks like a quarter) that can be replaced by the user simply by popping it out (although sometimes its very hard to do physically because many other components are in the way).

There is also a difference in the actual location of the battery, some computers having the battery built-in the motherboard while others have the battery free-standing and connected to the motherboard with a 4-pin 2 wire cable. Only pins 1 and 4 are used.

The motherboards many times have a jumper close to where the battery connects to the motherboard. This jumper is used to select the battery connection type, as internal or external. You could have a battery on the motherboard and erroneously set the jumper to the external setting causing the computer to NOT think it has a battery at all.

The battery voltages vary from 3volts to over 6 volts depending on the computer.

The life expectancy of a battery is 5 years on the outside. Some can go out as early as 2 years. The battery can be tested with a volt meter but is not recommended unless you feel very comfortable working with electronic equipment. Also taking the battery out of the computer poses the problem of plugging it backwards when you try to reinstall which can cause many problems.

A dead CMOS battery can and will cause the computer to loose the pre-configured settings such as Hard Drive type, amount of memory and other settings that are critical to the operation of the computer.

If a battery dies, you will know the next time the computer is turned on because it will warn you of the fact that the computer is not configured properly. In order to make the computer work you will at a minimum, have to go to the CMOS/BIOS settings and correctly set-up the hard drive parameters.

 

Battery Types - 

3.6v Lithium - 

Barrel Style solder-on

PS2 6 volt

Coin Cell

Rayovac 841 Alkaline

   

Connectors - 

Most CMOS batteries use the "Berg Connector" to connect the battery to the motherboard connector.

© 1997,98,99,2000 www.techadvice.com All rights reserved

---