Oneilkeys -- in your post 7 you said that plugging into 30 amp power only charges the house batteries not the chassis battery. I researched this extensively back in Feb and posted the thread
http://www.thorforums.com/forums/f10...when-3315.html specifically because I had heard the same thing from many other owners. It made no sense to me that if I were camped for 1 or 2 months and used the USB port on the dash (powered from the chassis battery) and the two 12 VDC ports (also powered by the chassis battery) on the dash to power 12 VDC appliances, TV, etc everyday, when it was time to leave and I tried to start the engine I'd be dead in the water because I killed the chassis battery using the USB and DC power points everyday for 2 month.
Here is what my research revealed:
The house and chassis battery will charge when on shore power or generator power through the charging circuit of the converter, or when driving down the road through the alternator. In the Vegas/Axis Thor does this through either a Battery Control Center (BCC) or a Bidirectional Isolator Relay Delay (BIRD) and Isolation Relay (Trombetta). Whether a BCC or BIRD/Trombetta the charging of the batteries work the same way.
First charging current will come from either the converter (if operating off shore or generator power) or the engine driven alternator.
Engine Alternator Charging the Batteries
When the ignition switch is turned on and the engine is running, the charge monitoring circuit in the BCC or the BIRD senses the level of voltage on the chassis 12 volt system. When this voltage goes above 13.1 volts for approximately 2.5 minutes, as happens when the engine is running normally (normal alternator output voltage of a cold engine is approximately 14.4 volts), it will close the BCC's isolator relay or the Trombetta providing charging current to the coach battery. This delay allows a cold engine an opportunity to start and warm up before having the heavy load of a discharged coach battery placed on it. If the voltage should fall below 12 volts for more than about 1 minute, the relay or Trombetta will drop out to feed all the alternators available output to the chassis battery to keep the engine running. This might happen when the alternator is not able to supply sufficient current to all of the loads and charge the coach battery at the same time. When the chassis voltage goes above 13.1volts again, the relay or Trombetta will again close in about 2.5 minutes to retry to charge the coach battery. The resultant flickering of lights would alert the driver of the system overload.
Converter Charging the Batteries
When the coach is plugged into shore power or the generator is running and the ignition is off, the BCC or BIRD senses the voltage on the coach batteries. When this voltage goes above 13.1 volts for approximately 2.5 minutes, as happens when the converter isn't heavily loaded, it will close the BCC isolator relay or Trombetta providing charging current to the chassis battery. If the voltage should fall below 12.6 volts for more than about 1 minute, the relay or Trombetta will drop out to prevent the coach loads from discharging the chassis battery. This might happen when the converter is heavily loaded by coach loads. When the coach battery voltage goes above 13.1 volts again, the relay or Trombetta will again close in about 2.5 minutes to retry to charge the chassis battery.
So while camping or driving down the road there are systems in the RV that ensures charging current is going to both the chassis battery and coach battery bank. The USE/STORE switch must be in USE for he coach batteries to charge regardless of what charging circuit is being used.
If the chassis is not charging off shore or generator power or the coach batteries do not charge going down the road -- something is either not working correctly or something was incorrectly wired in the BCC or the BIRD/Trombetta. After the thread I posted in February, several owners found their Trombetta was not wired correctly by Thor.
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