How to install Second battery

[duca1991]

Sorry to bring up an old thread, Just wondering about my charging system, i have an ex police omega with a dual battery setup and a 140amp high output alternator, i took out the redarc isolator and replaced it with a stinger 200amp isolator as my system running off the second battery draws more power than the redarc could handle (60amps) The stinger isolator is strictly for battery isolation and has no special volt regulator and fancy stuff ect like the redarc. I've had this setup with the stinger isolator for about 6 months now all connected together with fuses between batteries and 0 gauge. I notice that with the car left off over night in the morning the volts will be on 11.8v to 12.0v on both batteries. The car cranks fine but its charging at around 14.8v to 15v constantly and the battery % is showing 32%. So out of curiosity i got a cca battery tester to test the condition of both batteries..
My starter battery gives out 612cca which is perfect (both batts are 600cca). Now the second battery is showing 510cca. It seems my second battery is not being charged properly... My system is running off the second battery but once the cars started up both batteries link together so i dont know why my second battery would be drained even with my system running off it. i have only 1200rms. I have no idea how much the cops treated the batteries with the sirens and their gear, the car is a 2010 december model so the batteries would be almost 4 years old. Any help would be apresiated

 

[duca1991]

bump bump bump

 

[Aussie Willy]

depending on your second battery, most deep cycle battery's don't take kindly to unfiltered charging.
you may have answered your own question here "i took out the redarc isolator and replaced it with a stinger 200amp isolator"
also, if your pulling more than 60 amps from your second battery....do you have a kettle in your car
Dual Battery Isolators - REDARC