I recently worked as a safety official at a robot tournament and I was appalled at how many builders used improper wire termainals (or none at all!) on their IFI Victor Speed Controllers. Some were so big that they were almost making contact with each other. This of course would result in a complete meltdown of your batteries, controller, and/or wiring system.
Don't let smoke happen to your robot. Use the right connectors. These #8 size Ring Terminals crimp directly to 14 to 16 gauge wire, and once screwed down to your controller, will NOT let go. Vinyl cover (removable) on each terminal helps insulate the connectors. (I personally prefer to remove the vinyl and use shrink wrap instead.)
Comes in a bag of 25 connectors. Get extras, you'll always need 'em.