I posted this under another topic, but probably better to start a new thread.
I'm considering an upgrade to my old converter in the future and figure it may pay in the long run to install a Magnum or Xantrex charger/inverter. It's been awhile since I had to read schematics, but it looks like all the converter is doing is charging the house battery and all 12V functions on the coach are powered by the house battery? That correct? Not sure if I'm just getting caught up in the semantics of converter vs. charger?
Second question, it was my understanding that the alternator charges both the engine and house batteries when the engine is on. However, I'm not sure I see any circuit connecting the house battery to the alternator UNLESS the main disconnect is turned to on. Makes sense, but I just want to make sure that's correct? When the main disconnect is off, my front monitor shows the house battery voltage fluctuating with engine RPM so my assumption was that it was charging off the alternator, but in looking at the schematic, I don't think that can happen unless the main disconnect is on. Can someone confirm?
Yes, the converter does charge the house batteries but since it is trying to hold the batteries at a set level once charged it is also providing power to anything using the 12V source. Some converters can be used to run 12V items without being hooked to a battery but most either do not or recommend against it.
The alternator charges both the house and coach batteries because it is connected to the isolator which allows charging current from the alternator to go to both battery banks but prevents the house load from drawing current from the engine batteries.
Others may chime in with more details but I have attempted to address the core functions involved.
Yes, The basic function of a converter vs. charger are the same. Converters are just a 13.5 volt (or so) power supply. A charger is more sophisticated with with multiple stages and is designed for charging a battery. Converters have the reputation of overcharging a battery over long periods and ruining the battery.
If you coach is equipped an isolator, the alternator will charge both batteries through the isolator. It's an aluminum finned device with 3 or 4 post connections on it. The center post (or both centers if it has 4 posts) will connect to the alternator with the outside connections going to the house and chassis batteries. Simply put, it's two current check valves. One between the alternator and house battery and another between the alternator and chassis battery. All packaged together in an aluminum heat sink - because it will get hotter the more current it passes. The disconnect just remove most house loads on the house battery - doesn't have anything to do with charging. With the disconnect off the alternator will still charge the house battery.