[Al Skierkiewicz]

The sealed lead acid gel type batteries that we use do not die instantaneously like NiCads. You will find that a particular battery doesn't seem to last as long as it once did. Load testing is better than a voltmeter for testing but will not tell you the overall capacity of the battery. In these batteries the electrolyte is a gelled sulphuric acid that allows them to be used in any configuration. As they are charged and discharged a small amount of moisture is lost with each cycle. As moisture is lost, the amount of electrolyte that is in contact with the plates also diminishes. Eventually, there just isn't enough electrolyte for our demand and as the robot draws current heat builds up inside the battery causing further destruction. If a battery feels much lighter than your others, it is near the end of it's life. Use it for practice and then recycle.
You will find people that tell you to leave them on trickle charge, or charge every month to keep them topped off. Our batteries are stored at our playing field that is away from the mentor's place of work. We charge them when we need them. They have been charged maybe once since IRI in July for homecoming. We held a mini invitational this past weekend and all of them only needed a few minutes on charge to bring them up to full. Store them in a heated area, protect the terminals and don't leave them on the floor. If any have cracks in the case or the terminals move around also recycle.