CR V battery quickly empty

After just 2 1/2 weeks I can no longer start because battery was empty. Honda was completed by remote control, no forgotten lights etc. Diesel, 4WD, 9 Gang Automatic, EZ March 2018……… Edit: The CR-V, new vehicle executive stood at the dealer’s exhibition for 43000€. I had had a trailer coupling installed before delivery March 2018. At home the approx. 2 weeks before home….starting was not possible, battery was empty. The Honda workshop has been looking for errors for a long time. I had to believe it. Well, it was repaired and I installed a battery monitor with an app for the iphone in parallel. I noticed that almost never reached 12 V at rest, always around 11,8-9. They said that Honda was the “normal”….. In the meantime I don’t even have 14000 km because mostly with other vehicles on the road. But if I want to use the Honda after 2 1/2 weeks and I want to use the Honda after 2 1/2 weeks and I have not even only the battery has to charge again is certainly not normal. Have middle indication the opening button from the trunk could be defective. Thanks for this!