Before you slap a trickle charger on it, make sure to check your battery’s charge with a multimeter—if you don’t have one, go out and buy one. You’re checking the battery’s state of charge and if it needs a little juice or if you should just recycle it and get a new one. With the bike’s key in the on position, connect your multimeter. If the state of charge is over 12.73 volts, your battery is in great shape. Above 12.06 volts means it needs some charge applied and will be fine, but under 12.06 volts and you should be looking for a replacement.