Solenoid between the chassis batteries and the generator battery

[pattypape]

Hi All with gennie charging problems,

In addition there is a 70amp Bosh relay that is energized by the 12V
ignition for alternator charging, Or 110V shore power to charge the
gen. battery. It is located near the big fat diode. Look for lots of
road crud, corrosion and wire connector crimps. There is also a
glass fuse in the left front load center, that could be a problem.

Bill 88 FC Michigan


--- In WanderlodgeForum@yahoogroups.com, "Jeff Miller"
wrote:
>
> This is normal.
>
> The diode is like a one-way-valve for the power. It is supposed to
> allow current flow from the main batteries and charging systems to
> the generator battery so that the generator battery stays charged,
> but not allow current flow from the generator battery to the house
> batteries so that the house battery useage can't discharge the
> generator battery. A series circuit-breaker protects the wiring
and
> diode from damage in high-current situations like cranking the
genset
> with a dead genset battery.
>
> I don't remember what year this started, I believe '83 on the PT
> and '87 on the FC? Prior to this system the FCs used a "battery
> isolator" located just rearward of the house batteries (started
> around '82). This isolator wiring changed in '83 or '84 also, but
by
> now most of the isolators have failed.
>
> A retrofit has been around for more than a decade to add a diode
and
> circuit-breaker in series between the house batteries and genset
> batteries on the FC, usually located at the Aux. Start relay under
> the entrance steps.
>
> If this diode fails, and they do, it usually fails open. If you
can
> light a 12v bulb with the disconnected genset positive lead, it is
> likely good as is the circuit-breaker. It is more difficult to
check
> for a short, but you could disconnect the house batteries and all
> charging systems and see if the house positive lead will still
light
> a 12v lamp (like a brakelight bulb).
>
> As likely as a failure of the diode is a weak connection somewhere
> which will show 12v on the battery cable, might light a light, but
> not enough current would pass to keep the battery properly
charged.
> You could try something with a larger 12v draw such as a spotlight
or
> 12v compressor to test the diode circuit for a weak connections
(or
> visually).
>
> - Jeff Miller
> in Holland, MI
>
>
> --- In WanderlodgeForum@yahoogroups.com, Curt Sprenger
> wrote:
> >
> > Jeff,
> >
> > On our '87 PT38 the gen. positive battery cable is still hot
when
> > disconnect from the gen. battery. Would this this be a bad
diode?
> Thanks!
> >
> > Curt Sprenger 1987 PT38, Anaheim Hills, Calif.
> >
> >
> > Jeff Miller wrote:
> >
> > > The generator battery is charged via a stud-mount diode in the
> > > charger compartment, not through this solenoid.
> > >
> > > - Jeff Miller
> > > in Holland, MI
> > >
> > > --- In WanderlodgeForum@yahoogroups.com
> > > , "mrkane1952"
> <mrkane@>
> > > wrote:
> > > >
> > > > My local NAPA stocked a replacement relay which is
externally
> the
> > > > same, NAPA-Echlin ECH ST84. The solenoid is marked "50-12V"
> > > > and "6AC." This resembles the markings on my original which
are
> > > > only partially legible. Price ~$38.
> > > >
> > > > I'm replacing it as I, too, am having generator battery
charging
> > > > woes.
> > > >
> > > > M.R.Kane
> > > > '85 PT40
> > >
> > >
> >
>