batteries have always been the weak link in the system,what type pack ni-cad,nimh,other.nicads have been the most reliable and i will continue to use them till i hear better reports on the other types.i do a range check on any new plane installation and not the 100 foot kind i am talking of walking till the plane is barely visible,pointing the antennae at it and moving the controls in the predetermined pattern discussed with the helper.any movement on the way out or way back is considered a failure and plane is not flown till cause id found.after that range check it is only repeated at the beginning of a new flying season otherwise at the beginning of a flying sesion the quick easy antena down 100 ft check is done,before taking off all control functions are checked for proper operation and then go.needless to say that during assembly all wires are checked as well as clevises and engine bolts,muffler bolts.as part of pre-flight.not much else you can due.all but two of my crashes which are a total of 9 in 34 years were batteries going dead,only one time it was the tx battery the rest were flite batteries most of these occurred in the early seventies before i bought a lr taylor super cycler.back then we had four wire servos upto about 1972 and if one cell in a pack went bad the whole flitepack would no longer work.