The battery is couple years old now & it going dead overnight or 8 hrs or so parked. So I have experience working on these types of problems & have done the tests with the multimeter in series with battery disconnected to check amp draw. With the meter set on 200ma & everything off, the meter indicates between 16.5 -21.5, which I assume is total miliamp draw.

Per the Honda Service manual for the multiplex Sleep/Wake up system test it gives a value of less that 35ma parasitic draw as the system goes to sleep (45sec).

This leads me to believe it's the battery, however after I charge the battery the voltage drops to less than 10v after setting just a few hours. Looking for confirmation or suggestion on my diagnostics.
Thanks

 

Does the battery voltage drop while its disconnected?

 

Battery voltage after sitting overnight is 10.75v. I'm going to have battery load tested today. The charging system seems okay at 14.4v. I'm thinking it is the battery.

 

Battery tested bad- low cranking amps. New Diehard installed. Hope it lasts