have two 7.4 volt batteries ( 1 of 4000 mah and the other of 5600 mah) connected to a smart-fly super regulator then have the reciever leads "Y" to a single lead into the reciever?

Im testing a 7 channel 2.4 reciever on my eurofighter and dont have a separate channel for the other lead so I've decieded to Y them. Is there anything I should be worried about except that I have a single point of failure now?

Thanks

Luis