Originally Posted by tenbear
Trombeta is the brand name for a solenoid that connects the house battery to the chassis battery when the engine is running.
BIRD stands for "Bi-Directional Isolator Relay Delay" which allows either the House system (converter) to charge the chassis battery or the engine generator to charge the house battery depending on which circuit has the higher voltage.
Google "rv bird relay" for more info.
Edit: Older RVs used a Trombeta while newer RVs use a BIRD. Mine has a Trombeta that lasted about a year before failing. I replaced it with a similar solenoid, not a Trombeta, from eBay which has lasted for about 10 years without a problem.
Not exactly. Different RVs may not use a BIRD, but the Trombetta and BIRD serve two different functions. The BIRD (used in some but not all Axis/Vegas) actually opens and closes the Trombetta (which is nothing more than a dumb solenoid). The BIRD senses the voltage in the battery banks and opens/closes the Trombetta to allow both battery banks to charge off of either the alternator, generator or shore power. The Battery Control center (installed in some Axis/Vegas units) serves the same function and may or may not work in conjunction with a BIRD/Trombetta.