First verify the amperage with another ammeter, even the kind that clamps on the alternator wire is good enough for this test. Repeat test on battery cable, should be close to the same.

If there is  40 amps [or anywhere near that much] going to the battery, the battery is probably nearly shot, substitute a known good battery, and see if amperage drops to an acceptable level.

Finally, 14.5 volts is too high for a continuous chasrge, check with a known accurate volt meeter.
Contiouous charging voltage should be below 13.5, better 13.2-13.3 to keep from boiling all the water out of the battery.