Thor Forums

[bevedfelker]

Attached is a copy of the troubleshooting guide I have for RV Custom Products TH-1020 Battery Control Center found in newer Axis/Vegas models. Here is what it says about coach and chassis battery charging. It pretty well describes the charge levels needed for the BCC to switch between battery banks, and a description of how those banks are isolated from each other:

The interconnect relay parallels the coach and chassis batteries in the event it is desired to start the vehicle with a dead chassis battery. In addition, the relay controls charging of the batteries as a set. When the auxiliary start button at the driver’s console is pressed, a ground will appear at P1-1. When not pressed, P1-1 is approximately +12vdc, measured with a high impedance voltmeter. Pressing the auxiliary start switch pulls in the interconnect relay immediately by way of the interconnect relay driver. Note that when the switch is released, the relay remains closed for about 2 sec. This is the normal delay built into the relay driver.

Normal charging of chassis and coach batteries as a set depends upon the source of charging. For example, if the coach is under way, when the chassis battery charges to 13.2vdc from the engine alternator, the interconnect relay will pull in after a 10-15sec. delay. If the engine were to be turned off, when the chassis/coach battery set discharges to 12.6vdc, the interconnect relay disengages after a 2sec. delay. When the coach is on shore power and the coach battery disconnect is engaged, the converter will charge the coach battery until it reaches 13.2vdc, at which time the interconnect relay will close after the 10-15sec. delay. As before, should shore power be disconnected, the coach/chassis battery set will discharge to 12.6vdc and the interconnect relay will release after a 2sec. delay. The interconnect relay requires 0.75adc for its coil whenever it is engaged.


I also uploaded another document I have showing the BIRD and Trombetta (isolation relay) setup on many of the Vegas/Axis so you can read how that integration works and look at the block diagram for how they are wired.