i have a 79 Toyota pickup. over the years i have added more lights, bigger stereo with an amp. on board air system, CB and ham radios. i have noticed that I'm starting to draw a lot of amps when i have any number of my accessories on. i have replace the alternator and the voltage regulator, but haven't Reilly up graded the charging system. i am now at the point where a second battery would help a lot i think with my draw problem. what are some setups that others are running and what up grades have you done to your charging system. how are some of your dual batteries hooked up, such as to a switch or a relay or something. any input would help.