Motorcycle Repair: Eletrical system, kawasaki vulcan 750, 1993 kawasaki vulcan 750

Question
I have a 1993 Kawasaki Vulcan 750. I recently bought it off a friend. The one problem that it has is that you have to plug it in to a trickle charger every time you park it. The mechanic told him that he could pay to have the part replaced or use the trickle charger forever. He chose to use the charger and gave it to me when I bought the bike.The charger is the kind that shuts off to prevent over charging. My problem right now is that where I live its getting cold so when I try to start it: choke, half choke, or no choke it may not fire right up. But I only get a few tries and the battery taps out and I have to wait until it charges up. The other day I went around the block, stalled it out at a stop sign (I'm just learning to ride) and had to walk it back because the battery was dead. Here are my questions: Since my buddy doesn't remeber what the mechanic said was wrong with the bike do you have any Ideas? And, could this problem be directly related to the known problem or do I just need a new battery.I know my buddy has been using the charger for years and has ridden the bike right up to when he sold it to me. I had ridden it before I bought it also.
Or do I just not know how to start a bike because I'm a rookie? Any info would be helpful; I'm sure you get a million questions.
Thank you and Happy Holidays.
Jason

Answer
SOrry to say but I only work on Harleys. This might help though. Have the battery tested. If its bad replace it. If its good then you have a problem with the charging system somewhere. Problem is I dont know anything about a Kawasaki. This will get you started though. If you need to know more check with some of the other experts and they should be able to help.
Good luck and happy riding
Mike