Thor Forums

[TurnerFam]

what you've uncovered is exactly what I recently uncovered in my diesel pusher - and while our coaches may be somewhat different, the overall system for bi-directional connection/charging of batteries is probably the same.

I have a B.I.R.D., the bi-directional relay device, that controls the reading of the Voltage of each set of battery banks, and provides the TRIGGER to the 12v D.C. Continuous Coil, which is the 'link' between the two battery banks.
My 12v D.C. coil is a WhiteRodgers brand, but may only be different due to the size of the battery banks(Chassis = 2 12v, and House = 4 6v), but it essentially provides the same current connection between the two banks once the B.I.R.D. triggers it to 'connect', allowing 12v charging to flow to the 'other' bank.
When the Alternator is charging the Chassis bank, the BIRD waits until the Chassis batteries are at a certain Voltage level, then sends the signal to the 12v D.C. coil to 'connect' to the House bank.
When on Shore Power, or using the Generator, the opposite occurs - the BIRD waits until the HOUSE batteries are at a certain level before triggering the coil to connect the Chassis bank.

I also have an additional 'connection' coil, a Trombetta 12v Continuous D.C. coil, between the House and Chassis banks - controlled by the 'AUX' dash switch, or otherwise called a 'Battery Boost', which allows you to MANUALLY tie the two banks together, temporarily. If the house bank is low, it will give you the ability to add the Chassis bank to start the Generator, and vice versa if your Chassis bank is low and you need to start the engine, etc.
Rather than a BIRD automated device trigger, it uses a simple dash switch, telling the 12v D.C. coil to 'connect' while you are holding down the switch.


nice to know

I found all this due to my Inverter having a new issue of 'cutting off' for no known reason. I first thought that one of these 12v COILS was going bad, but after finding these and researching the system, realized that they are not part of the Inverter's 12v power source.
I then thought that it also might be the 12v Disconnect, which is a 'RV CUSTOM PRODUCTS' device, and uses the door-side switch... but it was also o.k.

Come to find out, after all the searching, it was actually one of the House batteries with two 'low' cells(specific gravity readings were very, very low).
The VOLTAGE would read fine on the battery bank, but once a substantial draw was called for from the Inverter, such as the Fridge compressor or microwave, the battery bank could not immediately give it the full 12v power it required, and the Magnum Inverter would then 'shut off'.
After removed the suspect battery, draining it, filling it with distilled water and giving it several good overnight full charging, and then filling it will new battery acid(auto parts store), and a few more overnights of full charging, it was performing fine again.

: ) and yes, sometimes these devices are mounted in places that are difficult to get to, but the factories try to find a 'close' place to mount them near the batteries since the wiring needs to be rather short.