While checking the charge on my battery this evening it occurred to me that maybe this might be helpful info to someone new to the hobby….. First, you solder a male JST plug to a male plug that is compatible with your Lipo battery (my favorite is EC3). Most 3 cell 1300 mAh Lipos will fit in the PSII battery compartment and the JST simply plugs right into the PSII. To charge the battery unplug the Lipo at the battery connector and remove the battery (leave the JST plugged into the PSII). So far, I have had excellent results with this upgrade to the Estes PSII Controller….