Cat alternator not charging

[Harold Prescott]

Hello Forum members,

First I have to thank the forum for helping out many times.
Ralph Fullenwider and Stephen Britles, for their help with my
headlight Mod.

Now as we are getting ready leave Northern California, I'm having a
problem with the cat alternator picking up the charge when switching
off the shore power.

My question,
Is there a relay that is failing or should I just change out the
alternator on the Cat?

Harold Prescott
'85 FC35
Marysville, Ca.

[w3ww]

Harold,

Before you do anything, check the voltage output at the alternator. Check it at
idle and also check at 1500 or higher RPM. Those older Motorola (I think that
may be the one you have) alternators seem to drop to about 10-11+/- volts at
idle and generate 13.8+/- at higher RPMs.

FWIW ....I thought I had a problem with mine and went to the trouble of taking
the alternator off, carting it to a NAPA test facility only to have them tell me
it was performing normally and it looked fine.

Don Mohney
87FC35
Jensen Beach, FL

[Non-text portions of this message have been removed]

[Harold Prescott]

Don
This alternator has been changed to a Delco....?amps.
I read across the alternator and found it's charging well. 12v or more.

With the engine running and nothing turned on I show a minimal
discharge. (probably from the clocks etc.) However the voltage drops
to about 11.75v.
I believe the reason for the low voltage after a start is related to
starting the eng.
However when changing from shore to coach power I'm not getting a
charge from the cat alt.
It charges with the genset just fine.
Is there a breaker that is failing to make the switch from shore power??

Harold Prescott
'85FC35
Marysville, Ca.



--- In WanderlodgeForum@yahoogroups.com, "w3ww" wrote:
>
> Harold,
>
> Before you do anything, check the voltage output at the alternator.
Check it at idle and also check at 1500 or higher RPM. Those older
Motorola (I think that may be the one you have) alternators seem to
drop to about 10-11+/- volts at idle and generate 13.8+/- at higher RPMs.
>
> FWIW ....I thought I had a problem with mine and went to the trouble
of taking the alternator off, carting it to a NAPA test facility only
to have them tell me it was performing normally and it looked fine.
>
> Don Mohney
> 87FC35
> Jensen Beach, FL
>
> [Non-text portions of this message have been removed]
>

[Jay Darst]

Harold,
Do you have a Redi-Line?

Maybe you have a big 12V load somewhere?

With the Cat turned off, what does the volt meter read? What does
the amp meter read?

Now start the Cat and idle it at 1,100 rpm.
Same questions, what does the voltmeter read? what does the amp
meter read?

Thanks
Jay Darst
85PT40
Springfield, IL


--- In WanderlodgeForum@yahoogroups.com, "Harold Prescott"
wrote:
>
>
> Don
> This alternator has been changed to a Delco....?amps.
> I read across the alternator and found it's charging well. 12v or
more.
>
> With the engine running and nothing turned on I show a minimal
> discharge. (probably from the clocks etc.) However the voltage
drops
> to about 11.75v.
> I believe the reason for the low voltage after a start is related
to
> starting the eng.
> However when changing from shore to coach power I'm not getting a
> charge from the cat alt.
> It charges with the genset just fine.
> Is there a breaker that is failing to make the switch from shore
power??
>
> Harold Prescott
> '85FC35
> Marysville, Ca.
>
>
>
> --- In WanderlodgeForum@yahoogroups.com, "w3ww" wrote:
> >
> > Harold,
> >
> > Before you do anything, check the voltage output at the
alternator.
> Check it at idle and also check at 1500 or higher RPM. Those older
> Motorola (I think that may be the one you have) alternators seem to
> drop to about 10-11+/- volts at idle and generate 13.8+/- at
higher RPMs.
> >
> > FWIW ....I thought I had a problem with mine and went to the
trouble
> of taking the alternator off, carting it to a NAPA test facility
only
> to have them tell me it was performing normally and it looked
fine.
> >
> > Don Mohney
> > 87FC35
> > Jensen Beach, FL
> >
> > [Non-text portions of this message have been removed]
> >
>