A lead acid battery makes electricity through a chemical reaction across the lead plates. Sometimes the lead plates start getting a light coating of corrosion across them and the higher amp charge will 'bubble' enough off to make the plates conductive with the acid again. Usually when I see that, it means you probably don't have a whole year left on that battery.
I just learned something about bike batteries.. Gotta Honda shadow my son rides. Thought I'd just start it up the a few weeks ago. It had been a good while since he last rode it. And I had failed to put in on the battery tender charger. Strange though, after not starting, I put it on the battery tender jr. and the light just blinked red indefintely. So I took off the battery thinking it was probably no good. Mentioned what had occurred to my bil and he said. Try charging it on a setting of 10 amps for about an hr. Be sure and only charge it not more than 1 hr and then switch the charger to 2 amps perferably 1.5 or 1 amp if you have one for 12 to 24 hrs. I did this put it back on the battery tender jr and the light went green after just a short while. Put it back in the bike and it fired right up. Apparently when they get down so low on amps you gotta give em a pretty good charge to bring the charge back up.
