User`s manual

PK2200108 s Backup Battery
Battery Life and Storage Conditions
The ten-year estimated life of a battery on the PK2200 is based on typical
use. Most systems are operated on a continuous basis with the battery
only powering the SRAM and real time clock during power outages and/
or routine maintenance. A ten-year life expectancy is an estimate that
reflects the shelf-life of a lithium battery with occasional usage rather than
the ability of the battery to power the circuitry full time.
The battery on the PK2200 has a 165 mA·h capacity. Older versions of
the PK2200 have a Toshiba clock that consumes 8 µA in idle mode.
Newer boards have an Epson clock that consumes 3 µA in idle mode. In
standby mode, SRAM consumes from a low of 1 µA (32K SRAM) to a
high of 8 µA (512K SRAM). If a system were unpowered 100 percent of
the time, the battery life with a Toshiba clock will be approximately
18,300 hours (2.1 years), and with an Epson clock will be approximately
41,250 hours (4.7 years). All life-expectancy ranges are based on normal
operating temperatures of 25°C.
Backup time longevity is affected by many factors, including the amount
of time the controller is not powered, and the SRAM size. To help
achieve a full ten years of backup, a larger capacity cell can replace the
BR2325. Alkaline batteries (mounted external to the board, like in many
PCs) can easily and cheaply give over ten years of backup.
The controller should be stored at room temperature in the factory
packaging until field installation. Take care that the controller is not
exposed to extreme temperature, humidity, and/or contaminants such as
dust and chemicals.
To ensure maximum battery shelf life, follow proper storage procedures.
Replacement batteries should be kept sealed in the factory packaging at
room temperature until installation. Protection against environmental
extremes will help maximize battery life.
Replacing Soldered Lithium Battery
Use the following steps to replace the battery.
1. Locate the three pins on the bottom side of the printed circuit board
that secure the battery to the board.
2. Carefully de-solder the pins and remove the battery. Use a solder
sucker to clean up the holes.
3. Install the new battery and solder it to the board. Use only a Panasonic
BR2325-1GM or equivalent.