Battery Tender Junior?
 

We purchased a battery tender junior today and got a little confused when reading the instructions. It says that if you have the battery outside of the vehicle, you have to attach a 24" (minimum) 6 gauge insulated battery cable to the negative terminal. Then, after you've attached the positive clamp to the positive terminal, you attach the negative clamp to the open end of the 6 gauge cable. Is that last really necessary? Can you just use the negative terminal instead of having another cable? Anyone have experience with this?

That instruction is there to keep any spark that might occur away from the battery. In certain circumstances, a spark near the battery can cause an explosion. I usually connect the battery charger before plugging it in to power. That greatly reduces the explosion risk. When disconnecting the charger from the battery, I unplug the charger from power first.

What Paul said.