Michael Bremer wrote:

Looking for some opinions and I know that there are no shortage of those
here.

I just returned from a little night ride to get my three landings and
noticed what appears to be an abnormal reading from the ammeter.

When on the ground, preparing for takeoff, I see a significant rise on the
ammeter when I switch the landing light and fuel pump on. I know that this
is normal, particularly with the landing light drawing a good bit of juice.

The question is...When applying full engine power for takeoff, the ammeter
rose off the scale. Not a sudden pop of the needle, but a pronounced rise
as the RPM went up. When throttling back to cruise power, the meter drops
to a more normal reading?

I'd say it's seems like a fairly flat battery being charged.
How long was it since that A/C was flown for a reasonable
amount of time ?
All batteries self-discharge at various rates depending upon
their chemistry.