Why does the gate open on its own during the day with nobody home?

It sounds like you have a Coromaster BIIB automatic gate opener that uses an electric motor to operate the gate, and you are experiencing issues with the gate opening during power outages or load shedding.
One solution to this issue is to install an automatic gate opener with a battery backup system. This system uses a battery to provide power to the gate opener during power outages, allowing the gate to continue to operate normally.
Another solution is to install a manual override system that allows you to open and close the gate manually during power outages. This can be done by installing a manual release mechanism that can be used to disengage the gate from the opener, allowing you to open and close the gate manually.
If you are not comfortable working with electrical devices, it would be best to seek the help of a professional technician. They will be able to install the necessary equipment and ensure that it is working properly.
It's also important to check with the manufacturer of your specific model of gate opener, they might have a solution or an add-on that can help you with this problem.

the back up battery has failed or is flat. It starts to work after sun up because the solar panel is feeding power to the system

Could be the unit is sensing more resistance in opening/closing during bad weather. That would seem to indicate the ERD is too sensitive. From the manual for a sliding gate: for a 1/2 hp motor, set dip switch A4 to on. For a 3/4 hp motor, set the dip switch B8 to on. Hope this helps. May want to also check if leaves or other dirt has gotten into the mechanism. Hope this helps.

Change the codes. There are usually dip switches in the remote and gate that can be switched. If it still happens, start looking at the receiver at the gate.

Maybe your key fob needs a new battery !
Power Liftgate Initialization

NOTE:If the power liftgate system is turned OFF in the message center, the system cannot be activated with any switches or with the liftgate handle. The system will need to be turned ON for any power operation to occur.

NOTE:The power liftgate may not operate under the following conditions:

• a low voltage or dead battery.
• a disconnected battery
• a power liftgate that has been left open for more than six hours.
• a power liftgate that has been manually closed and left ajar.

If any of these conditions has occurred, the power liftgate must be reset.

1. Manually close and fully latch the power liftgate.

1. NOTE:If the power liftgate does not open during this step, refer to the symptom chart to diagnose the power liftgate for no operation.
   Power open the power liftgate by using the keyfob or overhead console switch.

1. Once the power liftgate is fully open, close the power liftgate by using the keyfob or overhead console switch.
   This system can also set DTC'S
2. POWER LIFTGATE MODULE DIAGNOSTIC TROUBLE CODE (DTC) INDEX (BODY CLOSURES) 501-03 Body Closures 2004 Expedition/Navigator DIAGNOSIS AND TESTING Procedure revision date: 08/23/2004

   Power Liftgate Module Diagnostic Trouble Code (DTC) Index
   

   Power Liftgate Module Diagnostic Trouble Code (DTC) Index
   
   DTC Description Source Action B1342 ECU Is Defective Power Liftgate Module INSTALL a new power liftgate module. REFER to Power Liftgate Modulein this section. B2477 Module Configuration Failure Power Liftgate Module REFER to Section 418-01. B2522 Vbatt1 Circuit Failure Power Liftgate Module GO to Pinpoint Test B. B2552 Vbatt2 Circuit Open Power Liftgate Module GO to Pinpoint Test B. B2698 Vbatt2 Circuit Failure Power Liftgate Module GO to Pinpoint Test B. B2699 Left Pinch Strip Open Or Short To Battery Power Liftgate Module GO to Pinpoint Test B. B2700 Right Pinch Strip Open Or Short To Battery Power Liftgate Module GO to Pinpoint Test B. B2701 Left Pinch Strip Stuck Active Power Liftgate Module GO to Pinpoint Test B. B2702 Right Pinch Strip Stuck Active Power Liftgate Module GO to Pinpoint Test B. B2703 Open/Close Switch Stuck Active Power Liftgate Module GO to Pinpoint Test B. B2704 Optical Sensor Power Short To Ground Power Liftgate Module GO to Pinpoint Test B. B2705 Optical Sensor 1 Input Not Active During Powered Gate Movement Power Liftgate Module GO to Pinpoint Test B. B2706 Optical Sensor 2 Input Not Active During Powered Gate Movement Power Liftgate Module GO to Pinpoint Test B. B2709 Gate Open Output Short To Battery Power Liftgate Module GO to Pinpoint Test B. B2710 Gate Close Output Short To Battery Power Liftgate Module GO to Pinpoint Test B. B2711 Gate Open Output Short To Ground Or Open Power Liftgate Module GO to Pinpoint Test B. B2712 Gate Close Output Short To Ground Or Open Power Liftgate Module GO to Pinpoint Test B. B2713 Unlatch Output Short To Ground Or Open Power Liftgate Module GO to Pinpoint Test B. B2714 Uncinch Output Short To Ground Or Open Power Liftgate Module GO to Pinpoint Test B. B2715 Cinch Output Short To Ground Or Open Power Liftgate Module GO to Pinpoint Test B. B2718 Gate Ajar Output Short To Battery Power Liftgate Module GO to Pinpoint Test B. B2721 Gate Ajar Output Short To Ground Or Open Power Liftgate Module GO to Pinpoint Test B. B2722 Open/Close Switch Active During Self-Test Power Liftgate Module GO to Pinpoint Test B. B2723 Glass Position Switch Active During Self-Test Power Liftgate Module GO to Pinpoint Test B. B2724 Forkbolt Switch Invalid During Self-Test Power Liftgate Module GO to Pinpoint Test B. B2725 Detent Switch Invalid During Self-Test Power Liftgate Module GO to Pinpoint Test B. B2726 Home Switch Invalid During Self-Test Power Liftgate Module GO to Pinpoint Test B. B2819 Gate Motor Circuit Short To Battery Power Liftgate Module GO to Pinpoint Test B. B2820 Gate Motor Circuit Short To Ground Or Open Power Liftgate Module GO to Pinpoint Test B. B2821 Cincher Motor/Unlatch Actuator Short To Ground Or Open Power Liftgate Module GO to Pinpoint Test B. B2822 Cincher Motor/Unlatch Actuator Short To Battery Power Liftgate Module GO to Pinpoint Test B. B2825 Movement Ceased Due To Excess Speed Deviation Power Liftgate Module GO to Pinpoint Test B. B2903 Chime Output Circuit Short To Battery Power Liftgate Module/ Liftgate Chime Module GO to Pinpoint Test C. C1935 Chime Circuit Failure Power Liftgate Module/ Liftgate Chime Module GO to Pinpoint Test C. U1950 UBP Communication BUS Fault UBP Communi cation REFER to Section 418-00. U2338 Invalid ACM Message Data Power Liftgate Module
   

Check the antenna at the gate for corrosion at the connector and make sure it's not bent. Water can get in and make the connection intermittent. Also tighten the screws on the main control board where wires from the receiver connect.

I have a brand new Ramset 300 electric gate opener. My problem is in the early morning when the loop opens the gate it will not close unless deactivated manually. It does not happen later in the day with my GMC truck but happens early in the am with my husbands Toyota Prius. Please help. What can be the problem?

make sure the door handle on the outside has returned to normal position, sometimes the cold will make them stick. The door opens but the outside handle sticks open and the door won't latch. Hope this helps.

after you program the door, you have to push "sel" and override the load until the next setpoint.

Here is a quick try for you that works for me. Push the handle and make sure it is all the way returned to the closed position. Then try the lock, power or key. Then try and open. I have found that if the handle does not return to closed position it will not allow the lock to operate. Hope this helps and have a great day.