[legrandnormand]

Originally Posted by Chuck v

That dealer is really clueless...and may be at the root of some if not all of your problems.

I have a 2007 T40 C and can tell you what each battery bank is for, how it is charged and what to expect when not connected to shore power, etc.

1) The four golf cart batteries in the front under the windshield are wired in series / parallel to make a high capacity 12 volt storage bank to power the Xantrex inverter that supplies 110 AC to SOME of the loads in the coach like the refrigerator, microwave, etc. This set of batteries is charged on shore power through the Xantrex itself.

2) The diesel starting batteries (two 12 volt units in parallel so it still is 12 volts total...) in the right rear compartment near the rear axle only are used to start the motor. Normally these are only charged from the motor driven alternator -- but on my coach I have added a quality float charger that also can keep these topped off from shore power.

3) The "house" batteries are the remaining two 12 volt deep cycle batteries, also in parallel, in the same compartment as the diesel engine cranking batteries. These batteries supply all the low voltage lighting in the coach when the shore power is not providing derived 12 VDC from the 12 volt Converter. The 12V Converter is what charges these batteries.

It is also useful to understand how the transfer switches are wired in your T40 C... The Shore power comes into a transfer switch that is under the bed adjacent to the location of the Converter. The AC from the shore power (230v, 50 amp) goes Through a second transfer switch associated with the Diesel Generator and from there to two classes of loads. The primary loads are those AC appliances that do not run off the inverter (clothes dryer, air conditioners...) and the next set of AC loads are those that can be run from the inverter. Yes, the Xantrex inverter has its own internal transfer switch as well -- so if AC is present at its input it passes it to the loads and charges the golf cart battery bank. When AC is not present at the Xantrex inverter (no shore power AND diesel generator is not running...) then the inverter makes AC 110 from the 12 battery bank and supplies loads that are important, like the residential refrigerator.

The load disconnect switches at the step entry well of your coach select if the engine start batteries are turned off and if the house batteries are turned off -- these two switches control high current contactors in the rear compartment next to those batteries. These controls are clearly labeled "Coach" and "Chassis" with coach = house and with chassis = engine. Mine are always left on as I live in this coach. For long term storage you would turn these off.

You likely have more questions so please ask...

Chuck

X2 a great post Chuck with clear explanations, every owner should read this one.