Replacing the Coin Cell Backup power supply in a Handheld PC
CESD-H-0003 Applies to:
- Windows CE 1.0, CE 1.01
- Windows CE 2.0, CE 2.0 SP1
- Windows CE 2.11, CE 2.12 (Handheld PC Professional)
- Windows CE 3.0 (Handheld PC 2000)
Contents:
This article discusses the requirement of a Redundant Power Supply in models
of Handheld PC and their replacement procedure if using a coin cell.
FAQ:
Listed below are some common questions and answers to user questions
regarding the replacement of a Back-up Cell in a H/PC
A. When
should I replace the Coin Cell
If you Handheld PC
is equipped with a Back-up power source, you will be notified
by Windows CE when the Back-up Cell is running low. When the battery
begins to loose charge a warning Icon will be displayed in the
System Tray, next to the clock. When the power status changes
from a Low power state to a Critical power state a Warning Message
will be displayed on screen. At which time you should change the
Cell immediately.
You can also check the status of the back-up battery from the
Power applet in Control Panel.
It is important to maintain a healthy back-up cell in you Handheld
PC. As a result there is no intermediate Power Status stage in
the Back-up battery's level. Make sure to observe the Best before
date for your back-up source as a out of date battery could prove
ineffective against a main cell power outage.
A. Why
do I need to have a back-up battery
The back-up battery
is a redundant power source for your Handheld PC. It is not able
to provide power for device operation. The purpose of the Coin
Cell is to provide a constant supply of power to your devices
RAM. As the RAM is a Volatile Memory core, loss of power for any
short amount of time will cause it to be wiped.
An examples of when the Back-up battery is needed is in the event
of a main power supply failure. For example if your devices main
batteries fail during operation and the Handheld PC powers down,
the Coin Cell will provide charge to the RAM while the main power
supply is down, while the main battery's are physically missing
(e.g. being changed), or until the device is connected to a mains
socket.
Without the presence of the coin cell, within 15 - 240 seconds of a mains
power failure the devices Volatile RAM core will be wiped, a Hard Reset will
have been performed and all data in RAM will be lost.
At all times when there is sufficient power from a Main battery
or Mains Socket source the Back-up cell will not be drained. Establishing
a good power supply policy for your Handheld PC device will essentially
require you to change your back-up cell only when the expiration
date is reached.
A. Do all Handheld PC's have coin cell backup batteries
No. Unfortunately some manufacturers
opted to make use of alternate power solutions, such as AAA batteries. Additionally
there are a number of Handheld PC devices, for example LG and NEC ranges which
make use of internal, non-removable battery styles. Such devices often require
specialist technical assistance in the event that the integrated cell becomes
depleted and can no longer provide an adequate charge.
A. Which Cell should I purchase
The Cell / Coin Cell type may differ
depending on the Device & Manufacturer. Below is a list of Handheld PC
devices and required Cell types.
Note that not all of the devices listed below have user replaceable backup
batteries
|
Handheld PC
|
Cell #
|
Voltage
|
|
Ericsson MC12
|
CR 2032
|
3V
|
|
Ericsson MC16
|
CR 2032
|
3V
|
|
HP 300LX
|
CR 2032
|
3V
|
|
HP 320LX
|
CR 2032
|
3V
|
|
HP 340LX
|
CR 2032
|
3V
|
|
HP 360LX
|
CR 2032
|
3V
|
|
HP 620LX
|
CR 2032
|
3V
|
|
HP 660LX
|
CR 2032
|
3V
|
|
IBM Workpad z50
|
AAA x2 / LR03 x2
|
1.5v + 1.5v
|
|
Jornada 680
|
CR 2032
|
3V
|
|
Jornada 680e
|
CR 2032
|
3V
|
|
Jornada 690
|
CR 2032
|
3V
|
|
Jornada 690e
|
CR 2032
|
3V
|
|
Jornada 710
|
CR 2032
|
3V
|
|
Jornada 720
|
CR 2032
|
3V
|
|
Jornada 728
|
CR 2032
|
3V
|
|
Jornada 820
|
CR 2032
|
3V
|
|
LG Phenom H220
|
ML2430
|
3V
|
|
NEC Mobile Pro 200
|
CR 2032
|
3V
|
|
NEC Mobile Pro 400
|
CR 2032
|
3V
|
If you have any additional information on Coin Cell compatibility
please Contact Us.
How-to Guide:
The Coin Cell battery should be replaced
using the following procedure.
NB: This article is specifically written for the HP 300 series and the Ericsson
MC Series. Replacement procedures will be similar on other H/PC's, however slot
style and location may differ.
Before replacing your Back-up Battery. Ensure
that your main batteries are fully charged and or that your device
is 
connected
to mains power.
Have a back-up of your files and databases.
- Save all open documents and close all open applications. Power
Off your Handheld PC.
- Turn over your Handheld PC and carefully remove the Coin Cell
compartment door.
- Using the Stylus, carefully place the nib into the small slot by the side
of the Coin Cell and leaver the battery out of the slot.
NB: Be sure not to allow the stylus to slip forward as you leaver
the Coin Cell out of the slot as the stylus may damage the negative
terminal.
Insert
the new Coin Cell face up so that the Positive terminal (+) is pointing upwards
(See Image)- Push the Coin Cell snugly down into the slot so that it locks
into place.
- Place the cover back over the compartment.
You have now successfully replaced the Back-up Coin Cell on your Handheld PC.
You can safely continue using your Handheld PC normally.
If you wish to check on the status of the Coin
Cell's charge:
- Tap Start > Settings > Control Panel
- Open the 'Power' Applet
- On the 'Battery Type' tab change view the 'Backup Battery'
section to check on the overall status of the back-up batter
