This switched JST connector is the best way to quickly prototype with our LiPoly batteries.
Adafruit paired a genuine JST connector with a slide switch that can do up to 600mA. Both are soldered onto a breadboard-friendly breakout.
two ground pins, one 'switched' power pin, and one pin that is always on.
compatible with the "JST PH 2-pin" connectors used in Adafruits battery packs.