The BIRD MAIN function is NOT to charge the chassis batteries on a Newmar(Intellitec). Its function is to jump the coach Batteries to the chassis Engine Alternator to charge while in transit. That said, the secondary function of the BIRD is to charge the chassis while plugged into shore power if a condition is met. That condition requires that the Power Converter(Or Inverter/Charger) must be over 13.1 , for at least 2 minute. When the BIRD "sees" that voltage, it sends a 12 volt signal to the charge (boost) solenoid to close and that solenoid connects both coach and chassis batteries. Once the Power Converter(or Inverter/Charger) goes to float charge and that charge voltage drops below 13.1 volts the BIRD drops out and your chassis will not charge from the Coach charging system. Now, on your year Newmar, you have a small solar charger mounted directly above the drivers seat on the roof and THAT solar charger is installed to maintain the chassis battery system. You can still purchase a Intellitec BIRD. You do not have to go thru Newmar or change or update to what Newmar currently uses. You just need to verify that the charging system is functioning as I outlined. The BIRD is NOT want you think it is from your description. It is a small black box the size of a cigarette pack mounted in the Shore Cord compartment on the wall. Below is a link to what the BIRD is on your Newmar. Doug
http://www.intellitec.com/index.php/products/DC_Power_Management/Intelligent_battery_charging/The_BIRDthis is what the Big Boy solenoid looks like mounted in the shore cord compartment.
http://paneltronics.com/Datasheets/Big%20Boy%20200%20Amp2G_2pagedoc.pdf