Canon PowerShot SX10 IS User Manual page 257

Do not recharge the batteries until the LCD monitor displays
the "Change the batteries" message. Repeatedly recharging
batteries before they become depleted may cause batteries
to lose capacity.
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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