How is generator battery charged on an 82 FC?

[freewill2008]

> Ah ha. I've seen what I think is that isolator in
> the house battery compartment mounted on the back wall.
> There is a heavy cable that is pretty obviously
> disconnected from that isolator. I have no idea why,
> but this could easily be the cable of which you speak
> and would account for the dead battery.

For the genset charge circuit to work, there needs to be
a short cable from the center of the isolator to the
coach batteries, and a long one from one end of the
isolator to the combiner relay. If one of those is
disconnected, you have probably found the problem.

> Any idea why someone might disconnect that cable?

Good question. As I said, the BB system doesn't make a
lot of sense to the casual observer. It would be good
to follow the cables to make sure you don't connect one
end of a cable that has been left bare against the frame
at the other end.

There are copies of the starting/charging system wiring
diagram around. If you can't get hold of one I could
try to scan and post one of mine.

> It does seem as though the voltage meter on the
> generator reads higher when the main engine is running.

When alternator is spinning or the converter is running
you should see the voltage jump up about 1.5 volts. Watch
he meter carefully while someone else starts/stops the
3208.

I spent a lot of time and got plenty dirty before I was
sure what I had for wiring in our bus. There was stuff
disconnected on ours that didn't make any sense either.

BobG


>
> Kerry
> 82 Fc 35
> Denver
> --- In WanderlodgeForum@yahoogroups.com, "freewill2008"
wrote:
> >
> > The genset battery was set up at the factory to charge from the
> > convertor or the 3208 alternator. A solid state battery isolator
is
> > mounted in the battery compartment to prevent the generator
battery
> > from discharging along with the coach batteries. (Only two of the
> > three terminals are used on the isolator because the isoloater
was
> > not used for the coach batteries.) From the isolater there is a
> > cable that runs along the streetside frame rail until it crosses
over
> > to the generator tray. On its way to the genset, the charge
cable
> > from the isolator stops at the combiner relay which activates
from
> > your dash switch. (From the other side of that combiner relay
another
> > cable runs to the 3208 cranking motor. This is where the power
comes
> > from to start the genset when you hit the dash switch.)
> >
> > The factory design was not exactly intuitive. It takes some time
with
> > the wiring diagrams to realize how their design works. Some
coaches
> > have been modified in an attempt to "fix" the way BB wired it
> > (although it was not broken in the first place). You need to be
sure
> > the original setup or some viable substitute is in place and
working
> > or the genset battery will end up dead.
> >
> > Also, lots of coaches have been upgraded for separate house and
> > cranking batteries. If this has been done, charging current for
the
> > genset might have been overlooked in the re-design.
> >
> > Bob Griesel '84 FC31 WLII WA
>