Off Grid Power System

Hey Guys,

I'm a student and as a part of my project I'm working on I need to install a standalone/off-grid solar power system.

My configuration is 

Inverter: Axpert MKS 5K

Battery: SS202-05 (single unit of 7.4KWH capacity)

Solar panels: AE380hm6-72 (8units connected in 4-parallel combination of 2 serially connected panels)

Currently I'm testing the setup in lab with only 2 solar panel in series and with very limited sunlight available although I have mains/utility available. I am actually testing the situation when the battery gets discharged to a point (setting 29 - 48.5V) where inverter shut it down and connect the input to the inverter to see if it automatically switch on the battery or not. 

Inverter settings are for lab experiments are:

01 - Utl; 02 - 60; 03 - UPS; 04 - SDS;05 - Use; 11 - 10A; 12 - 47V; 13 - 51V; 16 - SNU ; 26 - 53.8V; 27 - 53V; 29 - 48.5V

Not sure about the 12 and 13 Setting voltage point back to utility source or battery mode 

1. I observed that it tries to switch on every half an hr. of duration and then picks up the mains/utility if connected.
2. I am not sure if this will happen on solar energy and if it will what level of solar input should be available to make it happen.
3. It happened that when battery got discharged and system was off it tries to switch itself on again with utility connected but battery was showing warning of cell voltage is too low which I managed to override by overriding the contactor switch. I feel like battery is running to a very low level before shutting itself off so that it doesn't even have enough juice left to be alive again when there is some input available (as it tries to switch on every half an hr. and for that it must have some power left in it).
4. Is the setting 29 - 48.5V is too low a value that it is making battery to run out of reserve power to try to switch itself on again once it is discharged?

Can anyone having experience with this explain me a little how does this thing works. Do we have a control over how often the inverter checks the status of input once it is in off state (battery discharged)

Thanks in advance