CMOS Battery
Content
CMOS BATTERY
1 of 4
http://murfsgarage.cybertechhelp.com/cmos.htm
CMOS BATTERY
When was the last time you thought about the battery in your PC? Didn't know there was
a Battery? Thats the battery that protects your valuable CMOS data when your desktop
isn't powered on. Most recent motherboards come with coin shaped lithium/manganesedioxide batteries that look like large watch batteries. These batteries are advertised to
have a life span of five years. That's longer than many people keep their PCs!
When should you replace your battery?
While the lifespan of the battery might be five years under the best of circumstances, why
would yopu wait until failure to replace? Remember that the battery is the only thing
standing between you and the loss of your CMOS settings when you power down your PC.
If you keep your PC long term without swapping out the motherboard, you should consider
changing the battery every two to three years. Why change the battery sooner? Simply this.
If you wait until the battery begins to die, your PC can forget its CMOS settings. And
remember its only about $3.00 to replace if you do it yourself.
Often, a dying battery will first manifest itself intermittently. Sometimes, you will boot with
no problem. At other times, you will see an error indicating that the system doesn't match
the configuration. When the battery fails entirely, the message will either come up every
time you reboot, or your BIOS may report an error number with a message stating that the
battery is dead.
If you have a voltage meter, you can check whether or not the battery is healthy by
measuring the voltage between the battery terminals that connect to the motherboard. The
voltage should be higher than 2.5 volts. If the voltage reading is less, you should change the
battery right away.
Before we change the battery lets look at several types of batteries motherboard
manufactures use.
Coin Cell Batteries
The most common battery used in todays computers .3 volt Lithium coin cell battery.
Replacement for CR-2032 computer battery.
4.5V Alkaline Batteries
4 pin connector. Velcro strip provided to attach it out of the way on the power supply or
case.
7/10/2011 12:29 PM
CMOS BATTERY
2 of 4
http://murfsgarage.cybertechhelp.com/cmos.htm
3.6V CMOS Batteries
3.6 volt ni-cad battery - 60mah - 2 pin connector - solder on.
Replacement for most soldered on "barrel" type batteries.If your motherboard has a 4 pin
connection near your old battery use B220 which you just plug on.
PS2 Computer Clock Battery
6V Lithium battery replacement for PS2 50 and up computer battery.
A good Internet Friend asked me about Laptop CMOS Batteries, so this is for
Goddess of the Toshiba
LapTop CMOS Batteries
Computer clock (CMOS or PRAM)batteries are used in virtually all laptop computer
systems that use CMOS memory to retain the date, time and configuration information when
the power is off. The types of devices used vary greatly depending
on the manufacturer and the application. Laptops may contain a clock/CMOS battery and a
resume battery to retain RAM memory information in the event the system battery loses
power. Some IBM compatible laptop computers contain a real time clock (RTC) battery and
a resume (somtimes called "sleep") cell. The RTC battery runs the clock and provides
memory back-up power for configuration (CMOS) information. The resume (or "sleep") cell
provides RAM back-up power when the main powercell fails. This allows the user to save
information in RAM to disk when the system is connected to power or a fully charged
battery is inserted into the system. Note: the resume function usually does not work the if
laptop's powercell is not in the systemSome laptops can contain more than one internal
battery to power clock, CMOS, resume and sub-battery functions. Type vary from Lithium
coin cells to Nickel Cadmium (NiCd) and Nickel Metal Hydride (NiMh) packs. These can
be soldered directly to the system board (or sub-card) or attached using a wire harness and
sub-minature connector.
Locations of these devices vary from model to model but, in most cases, these devices are
found underneath the keyboard. Some manufacturers locate the cells in odd places like
underneath a mouse ball, touch pad or in the screen frame housing.Use extreme caution
when removing the keyboard on any laptop! Keyboard assemblies are connected to the
system board by flat "ribbon" cables. These cables are usually made from Mylar™ (or
similar materials). Cable assemblies can be expensive and very difficult to find, even
through an authorized dealer.
ALERT - Many Compaq laptop owners are reporting that they cannot find a replacement
for the Rayovac BR1632 or that costs quoted exceed $50.00. Resource 800 can provide a
7/10/2011 12:29 PM
CMOS BATTERY
3 of 4
http://murfsgarage.cybertechhelp.com/cmos.htm
CR1632 with wire leads for $16.00, plus shipping (Please order the CR1632/WL). The item
is shipped as a kit with insulating shrink tube and Velcro fastener. Installation requires
cutting the old wire harness (with subminiature plug) off AT THE battery and soldering the
new battery leads to the old wire harness/connector assembly. SEE:
http://www.resource800.com/
Replacing a CMOS Battery on a PC
When you replace your battery, the CMOS settings will immediately be lost. In addition,
battery corrosion (more common in older PCs) or other battery problems may cause the
battery to die more suddenly than its expected lifetime. For this reason, it is important to
keep a record of your CMOS settings. Many utility suites, such as Norton Utilities, will
allow you to create a floppy disk backup of your settings. This can be extremely handy for
battery problems as well as recovering from other CMOS errors. If you do not have any of
these utilities then here's what to do!
Warning
Before proceeding remember to observe proper anti-static precautions when operating
inside the case of your PC. If you do not have a anti-static strap, rub your hands on the
metal portion of the case to get rid of static.
If you can't see your battery right away, try removing expansion cards or
unplugging cables. Most newer motherboards use lithium batteries that look like
large watch batteries.
Typical motherboard with a Coin Cell Battery
1. Boot your PC and enter its setup mode
2. Write down all of the settings from the various menus.
3. Power off your PC.
4. Open the case and locate the battery on the motherboard. See your user manual for
specifications about the battery
and its location.
5. Obtain a replacement battery from a local or online computer parts dealer or Radio
Shack.
6. Remove the old battery and replace it with the new one.
7/10/2011 12:29 PM
CMOS BATTERY
4 of 4
http://murfsgarage.cybertechhelp.com/cmos.htm
7. Document the date you replaced the battery.
8. Replace the case and power on the PC.
9. Enter your PC's setup mode.
10. Reenter the settings you have written down from the various setup
menus.
Congratulations you just replaced your CMOS Battery
7/10/2011 12:29 PM
1 of 4
http://murfsgarage.cybertechhelp.com/cmos.htm
CMOS BATTERY
When was the last time you thought about the battery in your PC? Didn't know there was
a Battery? Thats the battery that protects your valuable CMOS data when your desktop
isn't powered on. Most recent motherboards come with coin shaped lithium/manganesedioxide batteries that look like large watch batteries. These batteries are advertised to
have a life span of five years. That's longer than many people keep their PCs!
When should you replace your battery?
While the lifespan of the battery might be five years under the best of circumstances, why
would yopu wait until failure to replace? Remember that the battery is the only thing
standing between you and the loss of your CMOS settings when you power down your PC.
If you keep your PC long term without swapping out the motherboard, you should consider
changing the battery every two to three years. Why change the battery sooner? Simply this.
If you wait until the battery begins to die, your PC can forget its CMOS settings. And
remember its only about $3.00 to replace if you do it yourself.
Often, a dying battery will first manifest itself intermittently. Sometimes, you will boot with
no problem. At other times, you will see an error indicating that the system doesn't match
the configuration. When the battery fails entirely, the message will either come up every
time you reboot, or your BIOS may report an error number with a message stating that the
battery is dead.
If you have a voltage meter, you can check whether or not the battery is healthy by
measuring the voltage between the battery terminals that connect to the motherboard. The
voltage should be higher than 2.5 volts. If the voltage reading is less, you should change the
battery right away.
Before we change the battery lets look at several types of batteries motherboard
manufactures use.
Coin Cell Batteries
The most common battery used in todays computers .3 volt Lithium coin cell battery.
Replacement for CR-2032 computer battery.
4.5V Alkaline Batteries
4 pin connector. Velcro strip provided to attach it out of the way on the power supply or
case.
7/10/2011 12:29 PM
CMOS BATTERY
2 of 4
http://murfsgarage.cybertechhelp.com/cmos.htm
3.6V CMOS Batteries
3.6 volt ni-cad battery - 60mah - 2 pin connector - solder on.
Replacement for most soldered on "barrel" type batteries.If your motherboard has a 4 pin
connection near your old battery use B220 which you just plug on.
PS2 Computer Clock Battery
6V Lithium battery replacement for PS2 50 and up computer battery.
A good Internet Friend asked me about Laptop CMOS Batteries, so this is for
Goddess of the Toshiba
LapTop CMOS Batteries
Computer clock (CMOS or PRAM)batteries are used in virtually all laptop computer
systems that use CMOS memory to retain the date, time and configuration information when
the power is off. The types of devices used vary greatly depending
on the manufacturer and the application. Laptops may contain a clock/CMOS battery and a
resume battery to retain RAM memory information in the event the system battery loses
power. Some IBM compatible laptop computers contain a real time clock (RTC) battery and
a resume (somtimes called "sleep") cell. The RTC battery runs the clock and provides
memory back-up power for configuration (CMOS) information. The resume (or "sleep") cell
provides RAM back-up power when the main powercell fails. This allows the user to save
information in RAM to disk when the system is connected to power or a fully charged
battery is inserted into the system. Note: the resume function usually does not work the if
laptop's powercell is not in the systemSome laptops can contain more than one internal
battery to power clock, CMOS, resume and sub-battery functions. Type vary from Lithium
coin cells to Nickel Cadmium (NiCd) and Nickel Metal Hydride (NiMh) packs. These can
be soldered directly to the system board (or sub-card) or attached using a wire harness and
sub-minature connector.
Locations of these devices vary from model to model but, in most cases, these devices are
found underneath the keyboard. Some manufacturers locate the cells in odd places like
underneath a mouse ball, touch pad or in the screen frame housing.Use extreme caution
when removing the keyboard on any laptop! Keyboard assemblies are connected to the
system board by flat "ribbon" cables. These cables are usually made from Mylar™ (or
similar materials). Cable assemblies can be expensive and very difficult to find, even
through an authorized dealer.
ALERT - Many Compaq laptop owners are reporting that they cannot find a replacement
for the Rayovac BR1632 or that costs quoted exceed $50.00. Resource 800 can provide a
7/10/2011 12:29 PM
CMOS BATTERY
3 of 4
http://murfsgarage.cybertechhelp.com/cmos.htm
CR1632 with wire leads for $16.00, plus shipping (Please order the CR1632/WL). The item
is shipped as a kit with insulating shrink tube and Velcro fastener. Installation requires
cutting the old wire harness (with subminiature plug) off AT THE battery and soldering the
new battery leads to the old wire harness/connector assembly. SEE:
http://www.resource800.com/
Replacing a CMOS Battery on a PC
When you replace your battery, the CMOS settings will immediately be lost. In addition,
battery corrosion (more common in older PCs) or other battery problems may cause the
battery to die more suddenly than its expected lifetime. For this reason, it is important to
keep a record of your CMOS settings. Many utility suites, such as Norton Utilities, will
allow you to create a floppy disk backup of your settings. This can be extremely handy for
battery problems as well as recovering from other CMOS errors. If you do not have any of
these utilities then here's what to do!
Warning
Before proceeding remember to observe proper anti-static precautions when operating
inside the case of your PC. If you do not have a anti-static strap, rub your hands on the
metal portion of the case to get rid of static.
If you can't see your battery right away, try removing expansion cards or
unplugging cables. Most newer motherboards use lithium batteries that look like
large watch batteries.
Typical motherboard with a Coin Cell Battery
1. Boot your PC and enter its setup mode
2. Write down all of the settings from the various menus.
3. Power off your PC.
4. Open the case and locate the battery on the motherboard. See your user manual for
specifications about the battery
and its location.
5. Obtain a replacement battery from a local or online computer parts dealer or Radio
Shack.
6. Remove the old battery and replace it with the new one.
7/10/2011 12:29 PM
CMOS BATTERY
4 of 4
http://murfsgarage.cybertechhelp.com/cmos.htm
7. Document the date you replaced the battery.
8. Replace the case and power on the PC.
9. Enter your PC's setup mode.
10. Reenter the settings you have written down from the various setup
menus.
Congratulations you just replaced your CMOS Battery
7/10/2011 12:29 PM
