HP 48g Graphing Calculator - Manual (Page 440)

Environmental Limits
To maintain product reliability, avoid getting the calculator and
plug-in cards wet, and observe the following temperature and humidity
limits:
Calculator:
■ Operating temperature: 0° to 45“C (32° to 113°F).
■ Storage temperature: —20° to 65°C (—4° to 149°F).
■ Operating and storage humidity: 90% relative humidity at 40°C
(104°F) maximum,
Plug-In Cards:
■ Operating temperature: 0° to 45°C (32° to 113°F).
■ Storage temperature: —20° to 60°C (—4° to 140°F).
■ Storage temperature for RAM card data retention: 0° to 60°C (32°
to 140°F).
■ Operating and storage humidity: 90% relative humidity at 40°C
(104°F) maximum.
When to Replace Batteries
When a low-battery condition exists, the (<•>) annunciator remains
on, even when the calculator is turned off. When the calculator is
turned on during a low-battery condition, W - a r n i n g : LowB-at < ;■ is
displayed for approximately 3 seconds:
LouB-at (Pi ) refers to port 1.
LowB-at ( P 2 ) refers to port 2.
L o w E . d t ( S ) refers to the calculator (system) batteries.
Note Replace the RAM card battery or the calculator
batteries as soon as possible after the (<■ >)
low-battery annunciator and warning message
appear. If you continue to use the calculator while
the (!•)) annunciator is on, the display will eventually
dim and you may lose calculator and RAM card
data.
A-4 Support, Batteries, and Service