[Caddyroger]

Went to go to the store this afternoon but the battery was dead. Last week I accidentally hit the emergency flashers. My neighbor told me about them being on but it was to late the battery was almost dead. The car would not even crank over. I charged the battery back up it started up as usual.
The car as been parked for the last 3 days. This mourning the battery was dead but I do not know the reason. The only thing that was different was that I got a new cell phone charger and I have the aux connected directly to the battery. For the last 7 years I have had my cell phone phone charger being charged 24 hours a day 7 days a week. My car may set 6 to 7 days and the starter was fast and started right up.
Any one has any Ideals what caused this? The car will be setting until Wed mourning.