The lead acid battery is for a high current application (650 amp @ 3 min max) and the lithium is a house battery. The lithium is a 12.8v nominal. It charges to 14.6v then the BMS cuts off incoming charge. The resting charge is 13.2-13.4v. The lead acid is a standard 12v nominal. The resting charge is 12.8v. This is a 2 battery isolator. Does it matter which terminal a battery is connected to? Does the isolator give charge preference to one post over the other?