The standard silver calcium battery is a weird one, heaps of threads on exactly this matter. Don't throw it, charge it properly with smart charger.
Once the battery has lost charge you can't charge it in the normal way and it will keep going flat. Even the vehicle won't fully charge the battery. A special battery charger has to be used, that most dealers would by now have ordered.
There is 1.1 amps drawn from the battery while the vehicle is sitting in your garage. The BCM's, etc all draw power all the time. The new type of battery charger puts 120amps for the first few hours and then lowers the charge to around 50-60amps. It's all done in four stages. It takes 27 hours to fully charge the battery. This only becomes an issue if your battery has gone dead and you need to charge it up.
Using conventional chargers won't charge the battery fully (they only charge max around 16amps depending on your charger), meaning it will just die on you again sometime soon. Once fully charged the problem will be solved (until you draw deep cycling).
I've had my battery go flat about twenty times in two years, had to call Roadside Assist for jumps before I nutted out the issue.
RA techs nationwide are always puzzled by the readings, most said I needed a new battery when in fact the alternator simply didn't give it the required charge.
In rain (with three wipers, HID and stereo amps etc.) float can be dicey to leave enough HCA just after egress lighting draw!
Bottom line is the standard battery is brilliant as a starter, crap for cycling. Most retailers will sell you on an Optima Yellow Top D34 which has good balance of both - 750 vs 650 CCA + some extra cycling ah, costs $100 more.
But a solid smart high current charge from dealer will fix your silver calcium problem.
FWIW I CBF with it, bought a military-spec Odyssey with 1400 PHCA with 75 ah cycling, now can leave *everything* on all day with engine off and still end up crankier than the factory (short John) Silver. Arrr!
