Recently my battery has just been not holding a charge, it's the second battery to do this (albeit this battery is used (or refurbished)--cheap I know).
It's rapidly deteriorating to a point where a week ago, if I didn't drive the care within 48 hours it would be dead, now it's more like 24 hours.
I did a parasitic draw test, and upon initial contact it displays around 0.3 amps then lowers to 0.08 (I'm guessing that maybe as electrical devices in the car turn on, they transition into a power-saving mode?) the 0.08 doesn't seem to be enough to worry about, and certainly doesn't seem to be enough to drain the battery overnight.
When the car is running, the volts read 12.8~ with about 1500-2000 rpm, they go up to 13.5~ so I know the alternator is putting out power, but is that enough? Or is it reading lower because the battery is low to begin with?
I'm trying to rule out all causes before I buy a new battery. As of now I've disconnected the battery and will let it sit overnight, if it shows lower than what it was at (12.3v) prior to disconnecting, this is pretty much proof the battery is just bad rather than it being an alternator or electrical issue?