Random battery drain

[TimSattler]

I have a big problem, hopefully someone here has had the same issue and knows how to fix it. I have a 2023 Jayco travel trailer, 400 watt solar panel and Lithium battery. Sometimes I see a random big power drop while not running anything than the basics. I can get 28% drop in power over 6 days, even with cloudy conditions with trees all around, but then one morning I woke up and it had dropped over 60% overnight, I watched it for 40 min. more and it dropped another 6%. I fired up the generator, which brought it to 95% within an hour and every thing was fine for a couple of more days, then big drop, generator etc etc. I can't see anything obvious. Brand new battery. Could it be something weird with the fridge?

[Arch Hoagland]

Does the refrigerator go through an automatic defrost cycle?

[TimSattler]

It is a Norcold N7X, the specs say that at regular intervals the temp control system automatically melts most of the ice.