'83-84 GPZ1100 Battery

Hi, now that I'm on board, my first question is about getting my old 100GPZ back up to snuff. It needs a battery and since I first got the bike, I honestly don't have a clue to what that pink sensor wire that goes to the 3rd (or 4th) cell of the battery does. Low electrolyte? Low voltage? No matter what shape the battery was in, I never saw a warning light. A search on the forum found no answers. If you look at the cost of batteries, the stock battery with the sensor wire for this bike is $50 bucks more because of this cheap wire. The big difference is the reverse +/- orientation to the motorcycle frame. I've tried a regular battery and changed the cables so it would fit, let the bike side of the sensor wire dangle and there seemed to be no change to the way the electrical system worked.
Now I want to try one of those dry Odyssey batteries. So with that investment I want to make sure that pink wire is not needed. Does anyone know?
Thanks,
Stephen