My tractor battery died a year or 2 ago, so I bought a new one. Now that one is dead and I have been jumping it by carrying out a deep cell marine battery. I figure the options are that the tractor battery has gone bad, or that the charging system doesn't quite keep up with it. How do I know if the tractor battery has kicked the bucket? If I put it on the charger and it starts the tractor for a while, can I assume it's OK? I don't know what the heck I am doing most times.