Yes I have been following the other threads but still can't figure it out. I've got 2 group 31 agm batteries. They are a year old and will buy a new one for starting. One start and one stereo. I keep them isolated with the factory supra acr. I'm going to get a promariner prosport 20 amp charger. Do I just need a dual bank charger? One for the starting battery and one for the two stereo batteries wired together. These maintain batteries but what happen when my system reaches 13.8 and the isolator opens. Won't the charger see this as just one giant battery and not two isolated. Or do I need to get a 3 bank charger? And if so, how do I keep the two stereo batteries isolated from each other.