Amperage is higher when the battery is deeply discharged. Charging amperage is a function of the state of charge of the battery. In this example, it would increase output to 14.7 volts, which would result in the start batteries (and house batteries) seeing a charging voltage of 14.0 volts. The alternator increases charging output until the voltage read by the sense wire makes it happy. This is accomplished by the "SENSE" wire, which is connected to either the "Start" battery post on the isolator, or directly to a positive (+) post on one of the the start batteries. This is not enough to fully charge the batteries, so we must "trick" the alternator into putting out more charging voltage. So with 14 volts input at the isolator, the batteries in both battery banks will see about 13.3 volts. There is some voltage lost going through the diode "check valves". It routes the voltage from the center post to the 2 (or more) battery posts. The isolator is basically 2 one-way check valves.
That output goes to the center post on the isolator. In our coaches, with the typical OEM diode based battery isolator in place, the voltage put out by the alternator is controlled by the internal voltage regulator.
300 AMP SMART BATTERY ISOLATOR GENERATOR
Inverter has nothing to do with charging (when driving down the road)(with generator off). The inverter takes 12 volt DC power from your batteries, and changes it to 115 volt AC. First, take the inverter completely out of this discussion. Quote from: joe g - May 24, 2016, 10:18:54 am Just out of curiosity, in a situation were you have been dry camping and are now on the road and the engine is charging the house batteries, what controls the voltage and amperage going to the house batteries, the alternator/voltage regulator or the inverter? Tom beat me to it.