Hp prime lose date&hour when i change battery

[cyrille de brébisson]

Hello,

The real time clock needs power to work. No power means lost time...

However, the RTC uses VERY little power, and I have been successful in changing the battery without loosing the RTC, but 2 conditions needs to be meet to do so.
1) you need to minimize the power use of the calculator. To do so, place the calculator in deep sleep (press and hold the shift key, press the ON key, release the ON key and the shift key). This will kill power to ALL systems (including the RAM), except the RTC..
2) change the battery quickly.

Cyrille