The disconnect works well, but I would try and find the problem.
My dad had a model A where there was a drain in the battery. Turned out to be a short in the pop-out ignition - coil burned up one night and caught fire. Might be the one time you forget to turn it that you really find out what it is. Luckily the car wasn't damaged too much. 
On the positive side, it was 50 degrees in chicago this weekend, so I took the cover off my car to start it up. (unfortunately I don't have a garage, so it sits outside in the snow). Low and behold I forgot to turn the disconnect before I covered it for the winter - Battery was fresh and started right up. It's nice not worrying about having a dead battery.
John: Lake Forest, IL
'57 Fairlane 500 - Looking better every day.
