I’m using an AstroAl AM33D.
I replaced the alternator and battery about 3 years ago. My battery now sits consistently at 12.2 volts. When running the battery reads 13.9 volts without load and 14 volts under load (radio, fan, lights). After the engine is shut down the battery will uptick in voltage but will eventually settle back down to 12.2 volts.
When I check for a parasitic draw I get 0.56 amps.
The alternator is clearly charging the battery so it would appear that I have a failing battery.
My understanding is that with my meter set at 10 amps I shouldn’t see anything when I do the parasitic draw test. I don’t think .56 amps is a significant draw but, unless that draw is somehow related to an open hood, I’d have thought it would be enough to cause the battery to drop below 12.2 volts after not having been driven for a couple days.
DIYer advice: 0.56 amps is a significant draw.
Small car batteries have a capacity of around 40 amp hours.
https://homebatterybank.com/how-many-amps-is-a-car-battery/
40/0.56=71. So it would take around 71 hours (3 days) for that draw to make a fully-charged battery totally flat. And less time than that for the battery to be too flat to start the car.
I’ve read that an acceptable draw should normally be less than 50 miliamps, which is 0.05 amps. So yours is 11 times as big.
BUT, it may be that you took that 0.56 amps reading without waiting long enough for everything to go to sleep.