I never had a charger till i got the blade and tbh i dont always if ever put it on the fz1 and it seems to be fine but my bike is used regularly anyway. I was told when i bought the zx6 that even an alarm wont drain the battery so would be surprised if leaving the bike a few weeks will have any effect, maybe the battery is a bit duff anyway you dont know how its been looked after before you got it, but it wont harm to leave it connected, but let the wirw hang outside the seat if poss so you dont have to remove seats to put it on chargel