2023 Outback - Battery

[Navrig]

I have a 2023 Outback.  In January I will be acting as support to a cycling team doing a relay, 24 hour event.  It's a circular route meaning I will be static.  I am working out the logisitics for providing shelter and hot food for the 2 participants who are resting at any given time.  One option is to put the back seats in the Outback down and have a bed they can use to rest/sleep.  However I am concerned about the impact on the Battery of having the tailgate open all the time or it being opened and closed over a 24 hour period.  Hot food will be via a gas stove and flasks so no impact on the car.

Any thoughts or comments?