[hobbimaster]

Have you tried a different RX? IF its a spektrum RX, they use to have all sorts of problems shutting down, until sent in for updating. In any case you may also want to try a stutter stopper, or capacitor plugged into the RX so that if the voltage dips a bit low to the RX it wont shut down.
Personally I wont use anything under 5000Mah 25C in my rig, just to be safe. Since more and more PPL are jumping on Novaks HV we will see more frequent failures. As with anything electronic things will go south from time to time. But the best thing with Novak is that they have the fastest turn around time once something gets sent in.