I will try and explain better; just registering with cellular towers here is draining cellular phones batteries, even without sending or receiving anything. I was trying to solve the same problem for my phone only to realize that weak signal from several towers is causing the phone to "jump"...
Happened to me after one week. My hypothesis is that CARWINGS communication is draining the 12V battery because it happened at the night after I enabled CARWINGS, and where I leave the car cellular reception is terrible for all providers and usually drains mobile phones batteries within hours...
