Mines not getting used at the mo, when I put it back on I'll just charge it the night before,and when I use it I tend to just charge it up when the battery is low unless I know I need it for a big run, then I top it up the night before; I've no idea if thats right or wrong though. With other batteries (cameras in docking station) I've found continuous trickle charging bad for battery life.
edit: yip its a lithium-ion battery.