With this installation configuration, you will achieve full isolation
between your starting battery and deep cycle battery system. When the engine
is running or when an external charge source is applied to the starting battery,
both batteries will receive a charge automatically.
By using 8 AWG wire between the alternator and deep cycle battery,
you can use audio amplifiers that, in normal use, can have peak current draws in excess of
75 amps. The wire and BIC will tend to limit the alternator current to the deep
cycle battery. When the audio amp draws a peak beyond the 60 to 75 amp level, most
of the remaining excess is supplied by the deep cycle battery. When the peak drops
off, the deep cycle battery receives replacement charge current. This installation
method can work well when the average audio amp load is less than 50 amps.