second battery, 1986 cadillac deville

Okay I'm understanding what your talking about but when the car is in accesory mode the 2nd battery is in 12v but when you turn the car completely on its in 243 won't that damage my 12 volt devices . The batteries are wired in a pararell config.1993 sdv

Alpine 4x6 6x9 5 1/4 swr-10d4

alpine v60

12.5 VGA flip down

Nettop pc w/10" touch screen

78nova

5-re audio 5x7 ,10" sub &

Xtx-500.5

"Take the faceplate off get the jumperpack"

Thanks for all your help and concern. I wired radios before in car but I never had to deal with relays and upgrading charging systems and modifying so many wiring systems and using solenoids. The systems I've installed before didn't require so much power that a second battery is required. I'm aware that if u have a second battery your alternator will have to work twice as hard. Its to prevent a constant dead battery cause cadillac tend to use batteries a lot. If you want to get an idea on what I'm doing visit my website if you like. Thanks again for your help http://www.cardomain.com/ride/2238122 1993 sdv

Alpine 4x6 6x9 5 1/4 swr-10d4

alpine v60

12.5 VGA flip down

Nettop pc w/10" touch screen

78nova

5-re audio 5x7 ,10" sub &

Xtx-500.5

"Take the faceplate off get the jumperpack"