Thor Forums

[16ACE27]

Originally Posted by Beau388

Sorry to disagree but the purpose of the Trombetta relay and circuit module is to allow the batteries to interconnect. This is done by the emergency start switch or by the Trombetta control module. The module compaires the voltages between the chassis battery and house battery. If one battery is below 12.6 volts and the other is above 13.1 volts, after 2.5 minutes the batteries are connected by the relay. This allows the engine alternator to charge the house battery and the charger to charge the chassis battery. Newer coaches have a BIM instead of a Trombetta but it functions the same. Since the store/use switch disconnects the house batteries from the charger, neither the house and chassis battery would be charged if the switch is in the store position. Conversely if the store/use switch is in the use position, both the chassis and house battery will be charged by the charger.

Originally Posted by axis earl

Sorry back! It did NOT charge the chassis battery on our 2016 Axis which many of the other Axis owners confirmed. As we have said, check it out with a multimeter to know how it is actually working.

Originally Posted by Beau388

The class Cs built on Mercedes chassis do not allow the charger to charge chassis batteries.
From ED F. Vagas/Axis manual-

The coach is equipped with either a Battery Control Center (BCC) or a Bi-Directional Isolator Relay Delay (BIRD)and Trombetta (isolation relay)that performs two important functions. They provide a method of charging the coach battery from the engine alternator and charges the chassis battery from the converter when the coach is plugged into shore power. When neither battery is being charged, the batteries are isolated from each other to prevent the loads of one battery from inadvertently discharging the other battery.The BCC (ifso configured) is inthe storage compartment under the driver’s seat. It will probably be a RV Custom Products model TH-1020see Appendix 5).

The OP has a problem with his chassis battery dying after a few days. This is an abnormal condition, period.

Whether or not his chassis battery charges when plugged in is a completely separate issue and varies not only by the model of RV but also by different years of the same model.

The OP was concerned enough to start two new threads about his problem but has not returned to expand on his symptoms. Maybe he figured out he left the lights on which is easy to do in these Ford chassis RVs.