Lately I have been dealing with a lot of charging problems on 05-07 bikes.
If you bought the bike new then you would know if you have had to change the stator/regulator.
But if not check to see if you have a output "77" plug if so the regulator has been replaced.
But it sounds more like a stator issue. If you have a volt meter you can check it real quick.
Charge the battery test the volts should be roughly 12.5
Then disconnect the voltage regulator from the main harness ( it's behind the belt pulley cover)
Put your volt meter to the plug (with lock up ground is on the left) fire up your bike and rev it a couple of times and the volts should go up (no higher then 14.5 volt)
If its over that you have a regulator problem.
If not at all you need to check the stator.
Disconnect the regulator from the stator ground the black wire from your voltage meter to the timing over bolts fire up the bike and with the red wire touch each one of the 3 prongs ( not at the same time) it should read "0" on each lead. If not its the stator.
Good luck.