Hi Dennis,
Firmware 1.8.3 does not store the ‘disable/enable’ bit in EEPROM. So if the controller restarts, it will be put back into ‘enabled’.
The latest firmware 2.0.x (for OpenSprinkler V2) stores this bit in EEPROM so the status will be preserved over power outage. Unfortunately firmware 2.0.x will not work with your V1 hardware. The work-around is to turn off the power switch if you want the system to remain off for an extended period of time.