It may be necessary to enable certain functions during certain periods of time. These can be accessed on the H100 and H100+ within the AP3 parameter. When the user sets the summer time start date, the current time is subtracted by one hour. ex) [AP3- 04 Summer T Start] is set to April 1, and if it is 1:59 on April 1, it will not be 2:00 a minute later and it will be 1:00 on April 1. If [AP3-05 Summer T Stop] is set to Dec. 25, then it will be 1:59 on Dec. 25, and it will be 3:00 on December 25 instead of 2:00 a minute later. Summer time is different for each country. The parameter is based on 2 o'clock. If there is no charge on the RTC battery, it is initialized to 00:00 on Jan. 1, 2000 when the inverter power is off/on. AP3-1.