The stored values and settings remain saved in the meter while the batteries are changed or if the meter is stored without batteries. 

The meter has an in built back-up battery. This provides the power when there are no batteries inserted. The back-up battery lasts about 2 years and cannot be replaced if it is empty. An empty back-up battery has no effect on the functioning of the meter. 

If the back-up battery is empty the user has 10 minutes to change the batteries. If more than ten minutes elapses the meter forgets the time and date. When this happens, dashes appear on the display instead of the time and date. In this situation the time and date will have to be set again manually.