Canon Powershot A450 Advanced User's Manual page 90

Wipe the battery terminals well with a dry cloth in the
following situations, as the terminals may be soiled with oil
from one's skin or other dirt:
- If the battery usage time has considerably diminished
- If the number of recordable images has considerably
diminished
- When charging the batteries (insert and remove the
batteries two or three times before charging)
- When charging completes in a space of a few minutes
(the battery charger indicator remains lit)
You may not be able to fully charge the batteries due to
their specifications right after purchase or after long
periods of nonuse. If this happens, after fully charging
them, use the batteries until their charge is depleted. After
doing this several times, battery performance will be
restored.
If you store batteries for a long period of time (about 1
year), it is recommended that you deplete the batteries in
the camera and to then store them at room temperature (0
to 30°C/32 to 90°F) in low humidity. Storing them in a fully
charged condition can shorten their lifespan or degrade
their performance.
Again, if you do not use batteries for more than 1 year, fully
charge them once a year and deplete them in the camera
before storing them.
If the battery usage time has become considerably low
despite wiping the terminals and charging them until the
battery charger indicator remains lit, this may indicate that
the batteries have reached the end of their lifespan.
Replace them with new batteries. If you are purchasing
new batteries, look for Canon AA-size NiMH batteries.
Leaving batteries in the camera or charger may result in
damage from battery leakage. When not in use, remove
the batteries from the camera or charger and store them in
a cool, dry location.
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