Newmar electrical problem

[ricardo]

I've got a friend with an electrical problem. Here is the story.
Chassis batteries keep going dead even though the coach is plugged in. Today the coach batts were 13.5 and the chassis 7.4v. I know the batts are toast but can't figure why. The charger is taking care of the house batts but not the chassis. When the generator is running all batteries are charging. When the coach is running the alt. is charging all batteries. The Aux switch will not bring the house batts. on line. This suggests the relay and/or solenoid is not functioning. Also there is a 5 amp DC load on the chassis batts. even with the master disconnect (chassis) turned to off. I didn't have time to track that today. It seems that if the genset will charge both batts. the magnum charg/invert/convert should as well. Any thoughts would be appreciated. I can't identify the crossover solenoid and would appreciate knowing where it is located.
The coach is a 2002 Newmar Mountain Aire with a 400Cummins and 4096 floorplan. Thanks in advance. Rick

[dougrainer]

The solenoid AND the BIRD control is in the same compartment and is NEWMAR, not chassis. The Shore cord compartment is where the solenoid and controller (BIRD) is located. The BIRD does BOTH
1. Charges both battery banks when the chassis is running
2. WHEN the charge voltage from the Inverter/Charger goes OVER 13.2 volts, the BIRD closes that charge solenoid and allows the chassis battery bank to be online with the Inverter/Charger. Once the Inverter/Charger goes to Float charge and the voltage drops below 13.1 volts the chassis battery bank is no longer charging. There is NO difference between the APU or Shore running UNLESS, you have the Powertech APU, that as an option back then has a trickle charge module that would charge the chassis batteries as on Newmar Motorhomes, the chassis batteries start the APU.
You also have on that Newmar a Solar roof charger that was installed to charge the chassis battery bank for the parasitic draws caused by the Computer systems on the diesel chassis. IF the round Dash Solar light is NOT glowing red, get it fixed also. Doug

[ricardo]

Thanks that's a good start. Newmar says that the charger should charge both banks charging the house first then the chassis when plugged in and just the opposite using the alternator. Both Newmar and Spartan claim the other should know where the solenoid should be.

[Tom_Barb]

wolfe10 wrote:
Rick,

You are describing multiple (likely unrelated) issues:

Very hard to believe that the chassis battery is charged when on generator, but not when on shore power. Your converter, charger or inverter/charger really doesn't know the difference between the two sources.

It is not uncommon for the coach maker to wire the coach to charge the house battery bank from the converter, charger or inverter/charger but NOT the chassis battery.

And, as you state, the alternator should charge both banks when the engine is running.

With very low voltage on one bank, be careful about condemning a battery combiner solenoid. If it is powered by the battery with less than 12 VDC, THAT may be the issue.

Clearly, he needs to track down the 5 amp draw. That will take any battery bank down in just a few days.

The Onan genet will start and recharge the chassis battery on its own but will not charge the house batteries until the intelic control box tells it to.

He may have smoked the relay that the controller closes when the system requires it to, or he may have a bad controller or an open in the ground for the controller.

[Tom_Barb]

Does the coach have an intelic controller? it should be in the same compartment as the large cable that is plugged into the external power source. little square black box about 1"X4"X4" has 5 small wires going to it. If it has a good ground, check the voltage drop across the relay that connects the two systems together during a boosted start. That is the relay that will be closed when the inverter is charging the chassis battery.
Place a trouble shooting light across the relay and see if the light will light when the inverter is charging the house battery.

[wolfe10]

Rick,

You are describing multiple (likely unrelated) issues:

Very hard to believe that the chassis battery is charged when on generator, but not when on shore power. Your converter, charger or inverter/charger really doesn't know the difference between the two sources.

It is not uncommon for the coach maker to wire the coach to charge the house battery bank from the converter, charger or inverter/charger but NOT the chassis battery.

And, as you state, the alternator should charge both banks when the engine is running.

With very low voltage on one bank, be careful about condemning a battery combiner solenoid. If it is powered by the battery with less than 12 VDC, THAT may be the issue.

Clearly, he needs to track down the 5 amp draw. That will take any battery bank down in just a few days.