what kind of battery pack have you got [ 5 volt lipo] ? or 4.8 v nimh ? wont be lipo, a good battery pack for your receiver / servo power is a LiFe 2 cell. this pack will safely run both your receiver and servos at a safe power level, lipo batteries supply more voltage in 2 cell form 7.4 volts plus as opposed to the LiFe 2 cell at 6.6 volts. using non reghargeable AA batteries are ok but don,t last long so get yourself a charger that will charge Lipos / Life / Nicad and Nimh packs, look at Hobby King for these plus tx and rx battery packs [ cheap prices ] your throttle servo will probably last a while but you should look at buying something better with metal gears as so the rudder servo , 8 to 15 kg for throttle and 15 to 20 kg servo for rudder, this is what i use in my gas hydro and mono hulls without any worries atall.. a couple of good cheaper brand metal geaerd digital servos are the Power HD 20kg or the Savox 15 and 20 kg blue waterproof servos. i do like the Savox myself. these are available from Ebay sellers .