Battery problem

I am having a problem with my battery on my 1750 gtv. I periodically put it on an automatic charger as I drive the car rather infrequently. One day it started really slow so I put it on the charger. The amp meter as it would normally do started at 10 amps and then went down gradually over time. This time, however it stopped going down and stayed at 5 amps, per hour. Convinced the battery had about had it, it was about 7 years old, I bought a new "Ultimate" battery. I had the charging system checked and my mechanic said the regulator was intermittent and replaced it.
Anyway, when i try to charge up the new battery, the same thing happens. It goes down to 5 amps and then keeps trying to take a charge! I know the charger is good because I use it on my 3 other cars and it works normally.
Do I have a new bad battery?