Battery suddenly drained within days ?

Hello,I have installed my Video Doorbell 2 around january. Charged it fully and the battery lasted up until recently (bear in mind i live in Switzerland so the weather was pretty cold the 1st month or so). On the 2nd charge, it lasted a few days. Thought it was a mistake on my part, so i charged it again for 24 hours (including plugging it off and back on when the orange light was off) and after 24 hours of use, i'm down from 100 to 84%.The weather is much warmer now, I have it setup to the very minimal actions, ie not even logging activity. My wifi is not very strong (around 70-75 i think).So what has changed in the last month or so that could explain such a fast draining of my battery ?