Dome Solar power & battery size questions

Warning, this is a boring video I made. Please read the description as the narrative recording is similar to this written material. It is about the power needs for the Astronomy Club’s telescope and its accessories that are located in the Dome. The Dome requires manual slewing and tracking, it is not motorized. Would like some input from anyone regarding power needs.
Ran some testing at the observing field regarding the solar panels and did a power usage simulation as if it was a night of imaging. Made this video of the Electricity Monitor readings. Trying to determine the correct amp hours needed for a 12v battery during an imaging session. Then we need to evaluate the existing solar panels system we have and see if the solar panels’ charger controller produces enough power to recharge the battery. Would like to use two batteries in parallel.
The club has 7 solar panels, and each gave different voltage reads from 10v to 18v. Total reading on the connection points to the solar panels’ controller/charger was 18.95v. The solar panels are about 10-years old. Testing was done on a sunny day with temperatures in the mid 50-deg F.
I used my generator to provide power since the club does not have any 12v batteries anymore. All 12v items are as follows; telescope mount, dew controller (4 plugs) with only 2 dew strips connected, 7 port USB hub, LED lights (optional usage), all items plugged into a 12v 4-plug power hub. The 12v power hub was plugged into my 12v 10w AC/DC converter. I also had a laptop plugged into the same multi-outlet as the AC/DC converter was plugged into. The Electricity Monitor received the multi-outlet’s one pig tail plug. The Monitor was then plugged into the electrical cord going to the generator.
It seems that the average wattage during slewing events was showing between mid 50’s to 70 watts. Higher wattage did occur at times especially when I plugged in the laptop computer.
Thank you for any comments and advice.
Clear skies.