Ryon, just replace it with what's in there now (-;
The HS-5245MG is the Digital version of the HS-225MG. John has one in his new 45 SGX. It is working well and provides plenty of power for the 45 boat. He is using an 800 Mah 6.6v LIFE pack from Daniel Place. A great combination for the 21 boat also.good enough between 55 to 80 0z/in I like the HS-5245MG as same HS-225MG at my SGX 21 reason put good room RX battery "hump" If you install standard servo ( sample 645 MG ) but put no room battery