Canon IXUS 750 - Manual (Page 108)

You are recommended to use it in the camera until it is
completely discharged and to store it in an indoor location
with low relative humidity and between the temperatures of
0 - 30 °C (32 - 86 T).
Storing a fully charged battery for long periods of time (about one
year) may shorten its life cycle or affect its performance. If you do
not use the battery for long periods of time, charge it fully and
discharge it fully in the camera about once a year before
returning it to storage.
Charging the Battery
Since this is a lithium-ion battery, you need not completely
discharge it before recharging.
It can be recharged at any point.
It takes approximately 95 minutes to fully charge the battery
from a fully discharged state (based on Canon’s testing
standards).
• Charging it within a temperature range of 5 - 40 °C (41 - 104
°F) is recommended.
• Charge times may vary according to the ambient temperature
and the battery's charge state.
You are advised to charge the battery on the day of use, or
one day before, to ensure a full charge.
Even charged batteries continue to discharge naturally.
If the performance of the battery diminishes substantially
even when it is fully charged, its life has been exceeded and
it should be replaced.
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