ORIGINAL: Druss
the generic term for the connectors is EC3 I believe. If you already know how to solder the most important part is to completely finish one wire and get heat shrink on it BEFORE you even cut the other wire. Doesn't matter which you do first. This is to eliminate the possibility of a short circuit.
For traxxas connectors remember not to get any solder past the line or you'll have trouble fitting the tabs back into the housing.
Those connectors are not EC3. Those are 4mm bullet connectors.
HC got away from EC3. Their connector of choice on the smaller batteries is the XT60 connector. For the bigger ones, it's bullets.
This pic shows XT60 (yellow)and EC3 connector (blue)
[img]catalog/imageNA_sm.gif[/img]
These are the bullet connectors that are on the larger packs
[img]catalog/imageNA_sm.gif[/img]