Battery problems

Hi folks, Would be grateful for advice on a possible battery problem. I have a 2009 Bonneville SE which I use most days for work ( only about 10 miles ) , some evenings and most weekends for longer rides. I started it on the button on Thursday , drove to work , but it wouldn't start on my return so I resorted to bumping it. I checked the battery and it was below the required 12.7 volts needed. I charged it up , but the same thing happened again. I know it needs to be above 12.7v, and that short rides are not good, but it seems to slowly drop voltage when it is connected to the terminals. I notice that most owners seem to continually trickle charge their batteries, but I cannot do that as the bike is kept in a lock up garage ( with no power supply ) some way from home. I have put the meter across it when the bike is running , it reads about 13.6 v so I assume it is charging ok, and the battery does hold the charge when unconnected. I find electrics to be a dark art, so any advice would be appreciated.

 

Hi Steve, Thanks for your reply. The battery is the original ,so its five years old. I have taken your advice and ordered one of those batteries you recommended. It will be here on Wednesday so will let you know how I get on, thanks again.......Phil