A car we store for the winter in an un-heated garagehas the battery go dead with-in a month .And a couple of times the parasitic drain ruined a cell/battery.So we bought a Battery Tender for that issue.One doesn't need to be versed about an automobileor a BT to use one and solve a variety of problems.It's a worry free ~ wonderful product that completely monitors itself.You can leave it hooked up for weeks or months etc.All though you ought to check on it every once in a while.The cab light in our truck was left on overnight & wouldn't startthe BT restored it enough with-in two hours to turn the motor over.A battery must have at least 3 volts left or the BT won't initiate chargingThen your down to jumping it, if the battery isn't yet ruined.The cords of the Battery Tender Plus are ~Electric cord (box to outlet) 6 ft 2"longCable that clips to a battery (with clips attached - box to battery) 7 ftGiving a possible continual length of over 13 ft.If that's not long enough, the 25 ft BT extension is economicaland our experience is that the BT is just as effective weather the ex is used or not.Footnote: A warning in the instructions say ~ quote1. "If the positive battery post is connected to the vehicle chassis,then the vehicle has a positive ground system.2. If the negative battery post is connected to the vehicle chassisthen the vehicle has a negative ground system.(Most systems are negative)3. For negative ground systems connect the positive alligator clip to the positive battery post.4. Then connect the negative alligator clip to the vehicle chassis."Then it goes on to state several areas NOT to connect to.This language has always worried me what exactly was the right thing to do here.So I phoned Deltran Corp and asked.They said they have to state that to protect themselves butthat it's fine to hook both clips to the two appropriate terminals of the battery.I must say here that the folks at Deltran are very accessible ~ knowledgeable ~and offered comparison information between the BT Jr verses the BT plus ~ cheerfully.I was impressed with their customer service.