Probably the starter. Turn on the lights. If the light intensity is fine then the starter is the culprit.
Honda has redesigned this starter. The plate assembly that holds the brushes is a culprit and the brushes seem to overheat and prematurely wear out. Slow cranking and sounding like the battery is on it's last legs are usually the common signs. This slow cranking was evident from day one. Notice the signs of heat and slight melting on the assembly where the 2 brushes are totally worn out.
Just did another 05. Removing the intake manifold will save you a lot of time and frustration.
Got ripped off up here in Canada to the tune of $254 for a $102 part made in China that I had to pickup from the warehouse. Almost 150% mark up. Pointed this out to my now former
supplier who just smiled and claimed that shipping made a mistake on his invoice which, according to him, I should never have been allowed to see in the first place.
It cranks strongly now and all is well.
The brush/plate assembly is about $60 if you can get it.