Voltage Readings

[Scott Forman]

I don't know a lot about electricity, so I need some help here:

What should the voltage reading on the engine volt gauge be while
driving? I have always thought that when driving normally, the volt
gauge should read somewhere around 14.5 when the alternator is
putting out properly. Last night, when driving home from a repair
shop where several items were replaced (including 4 new batteries),
the gauge was only reading a bit above 12 when driving. Should I be
concerned about my alternator?

Also...what is the purpose of the 'Amps' gauges? What do they
demonstrate? My 82 FC has one on the dash and also one at the power
switch in the step well. Neither gauge ever seems to move much if at
all. What should these two gauges be showing me?

Thanks
Scott Forman
82 FC35RB
Memphis

[Curt Sprenger]

Dash Voltage - My experience is the dash volt gauge should read about
13.5 volts. Gauges get old and the calibration may be off, so with the
engine running, use a meter and take a volt reading at the alternator .
12.5+ is good, especially with the new batteries. Also take an AMP
reading at the alternator. If there are positive AMPs the alternator
should be good. AMPs will vary depending on the alternator load.

AMP Gauges - I'm not sure about the '82FC. The one in the step-well is
probable tied in with the generator and shore power. The dash gauge is
probable the engine alternator AMP output. With the generator running,
or hooked to shore power, and the power source set to GEN or SHORE,
check the step-well gauge with no load, then again with a couple AC
units running. No load = low reading...two AC units on = higher reading
of maybe 20 or 30 AMPs. Check the dash AMP gauge while conducting this
test.

Jeff Miller or others will add clarity to this I'm sure.

Hope this helps.

Curt Sprenger 1987 PT38, Anaheim Hills, Calif.



Scott Forman wrote:

> I don't know a lot about electricity, so I need some help here:
>
> What should the voltage reading on the engine volt gauge be while
> driving? I have always thought that when driving normally, the volt
> gauge should read somewhere around 14.5 when the alternator is
> putting out properly. Last night, when driving home from a repair
> shop where several items were replaced (including 4 new batteries),
> the gauge was only reading a bit above 12 when driving. Should I be
> concerned about my alternator?
>
> Also...what is the purpose of the 'Amps' gauges? What do they
> demonstrate? My 82 FC has one on the dash and also one at the power
> switch in the step well. Neither gauge ever seems to move much if at
> all. What should these two gauges be showing me?
>
> Thanks
> Scott Forman
> 82 FC35RB
> Memphis
>
>
>
>
>
>
>
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[John Suter]

Hi Scott,

--- Scott Forman <sforman@...> wrote:

> I don't know a lot about electricity, so I need some
> help here:

Let's first chat a moment about 12V batteries. To
charge at all, they must be presented with 14.1 volts
or more, and a fully charged, good, 12v battery, "at
rest" (i.e. without a load, and roughly an hour or
more after charging has ceased) should indicate 12.65v
while a "discharged" battery under the same
circumstances will show 12v or less. Note that if the
battery is not "at rest," measuring its voltage will
not present an accurate picture, and it really needs
to be checked with a "Load testing" device for true
accuracy.

It is common to hear an inverter/charger "float
charges" at 13.4 or 13.1 or so; however, "float
charging" is generally understood not to mean "adding
any charge," but to be an "in-between state" where the
charger system has determined charging (14v+) is no
longer needed, but monitoring is necessary in the
event charging becomes necessary.

> What should the voltage reading on the engine volt
> gauge be while
> driving?

Engine alternator charging is controlled by a
regulator system which adjusts both voltage (still
must be above 14v to charge) and amperage, which is
"current flow." The two readings are positively
correlated, though not necessarily, directly, in a one
to one relationship.

Voltage and Amperage can be read from the dash
gauges; however, the gauges are generally reading
totals and not simply the portion which is "battery
charging." Therefore, depending upon the regulator
settings and total system demands for current/power,
the regulator may provide voltages from 12 through 18,
and amperages from virtually nil to the maximum output
of the alternator. For most Birds, we'd not find it
unusual to see around 14 1\2 volts and 20-30 amps.
Significantly higher or lower of either, would be
cause to ask "why," but not necessarily become
alarmed.

> I have always thought that when driving
> normally, the volt
> gauge should read somewhere around 14.5 when the
> alternator is
> putting out properly. Last night, when driving home
> from a repair
> shop where several items were replaced (including 4
> new batteries),
> the gauge was only reading a bit above 12 when
> driving. Should I be
> concerned about my alternator?

With the engine running, turn on all headlights
and 12V circuits and see what you find, especially the
amperage.
No change, and assuming the gauges are reasonably
correct, I might be questioning the regulator. If it
is found normal, then the alternator.


> Also...what is the purpose of the 'Amps' gauges?
> What do they
> demonstrate? My 82 FC has one on the dash and also
> one at the power
> switch in the step well.

Generally, the one(s) at the step well are measuring
the amperage of the 110V circuit(s). When connected
to shore power, turn on an air conditioner compressor
and watch the amperage gauge.


> Neither gauge ever seems
> to move much if at
> all. What should these two gauges be showing me?

Hopefully, some of the above may have answered this
for you, Scott.

>
> Thanks
> Scott Forman
> 82 FC35RB
> Memphis

John Suter





__________________________________________
Yahoo! DSL – Something to write home about.
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[Scott Forman]

John,

Thanks for the wealth of information. I tested with a multi-meter
today, and it looks like everything is fine...I guess maybe the
voltage gauge is just tired.

Scott

--- In WanderlodgeForum@yahoogroups.com, John Suter
wrote:
>
> Hi Scott,
>
> --- Scott Forman <sforman@r...> wrote:
>
> > I don't know a lot about electricity, so I need some
> > help here:
>
> Let's first chat a moment about 12V batteries. To
> charge at all, they must be presented with 14.1 volts
> or more, and a fully charged, good, 12v battery, "at
> rest" (i.e. without a load, and roughly an hour or
> more after charging has ceased) should indicate 12.65v
> while a "discharged" battery under the same
> circumstances will show 12v or less. Note that if the
> battery is not "at rest," measuring its voltage will
> not present an accurate picture, and it really needs
> to be checked with a "Load testing" device for true
> accuracy.
>
> It is common to hear an inverter/charger "float
> charges" at 13.4 or 13.1 or so; however, "float
> charging" is generally understood not to mean "adding
> any charge," but to be an "in-between state" where the
> charger system has determined charging (14v+) is no
> longer needed, but monitoring is necessary in the
> event charging becomes necessary.
>
> > What should the voltage reading on the engine volt
> > gauge be while
> > driving?
>
> Engine alternator charging is controlled by a
> regulator system which adjusts both voltage (still
> must be above 14v to charge) and amperage, which is
> "current flow." The two readings are positively
> correlated, though not necessarily, directly, in a one
> to one relationship.
>
> Voltage and Amperage can be read from the dash
> gauges; however, the gauges are generally reading
> totals and not simply the portion which is "battery
> charging." Therefore, depending upon the regulator
> settings and total system demands for current/power,
> the regulator may provide voltages from 12 through 18,
> and amperages from virtually nil to the maximum output
> of the alternator. For most Birds, we'd not find it
> unusual to see around 14 1\2 volts and 20-30 amps.
> Significantly higher or lower of either, would be
> cause to ask "why," but not necessarily become
> alarmed.
>
> > I have always thought that when driving
> > normally, the volt
> > gauge should read somewhere around 14.5 when the
> > alternator is
> > putting out properly. Last night, when driving home
> > from a repair
> > shop where several items were replaced (including 4
> > new batteries),
> > the gauge was only reading a bit above 12 when
> > driving. Should I be
> > concerned about my alternator?
>
> With the engine running, turn on all headlights
> and 12V circuits and see what you find, especially the
> amperage.
> No change, and assuming the gauges are reasonably
> correct, I might be questioning the regulator. If it
> is found normal, then the alternator.
>
>
> > Also...what is the purpose of the 'Amps' gauges?
> > What do they
> > demonstrate? My 82 FC has one on the dash and also
> > one at the power
> > switch in the step well.
>
> Generally, the one(s) at the step well are measuring
> the amperage of the 110V circuit(s). When connected
> to shore power, turn on an air conditioner compressor
> and watch the amperage gauge.
>
>
> > Neither gauge ever seems
> > to move much if at
> > all. What should these two gauges be showing me?
>
> Hopefully, some of the above may have answered this
> for you, Scott.
>
> >
> > Thanks
> > Scott Forman
> > 82 FC35RB
> > Memphis
>
> John Suter
>
>
>
>
>
> __________________________________________
> Yahoo! DSL – Something to write home about.
> Just $16.99/mo. or less.
> dsl.yahoo.com
>

[John Suter]

> John,
>
> Thanks for the wealth of information. I tested with
> a multi-meter
> today, and it looks like everything is fine...I
> guess maybe the
> voltage gauge is just tired.
>
> Scott

Great! Happy to hear of problems that turn out
relatively minor.

Generally speaking, if a direct current (DC) voltage
gauge displays, but occasionally or consistently
appears "lazy," one likely culpit is a "poorly"
grounded meter. As a DC dash meter often shares its
"ground connection" with other nearby 12v devices, and
all are located a good "electrical" distance from the
negative battery ground post(s), be on the lookout for
similar "lazy" behavior from other 12v devices,
lights, fans, etc., especially when they are
collectively "on" and draw significant
amperage/current. Satellite dishes, and other circuit
boards fed with 12v, are particularly sensitive to
aging and poor ground connections and can be damaged.
When you "get your fill" of the poor/lazy behavior,
consider adding an additional ground wire.

John Suter


> --- In WanderlodgeForum@yahoogroups.com, John Suter
>
> wrote:
> >
> > Hi Scott,
> >
> > --- Scott Forman <sforman@r...> wrote:
> >
> > > I don't know a lot about electricity, so I need
> some
> > > help here:
> >
> > Let's first chat a moment about 12V batteries.
> To
> > charge at all, they must be presented with 14.1
> volts
> > or more, and a fully charged, good, 12v battery,
> "at
> > rest" (i.e. without a load, and roughly an hour or
> > more after charging has ceased) should indicate
> 12.65v
> > while a "discharged" battery under the same
> > circumstances will show 12v or less. Note that if
> the
> > battery is not "at rest," measuring its voltage
> will
> > not present an accurate picture, and it really
> needs
> > to be checked with a "Load testing" device for
> true
> > accuracy.
> >
> > It is common to hear an inverter/charger "float
> > charges" at 13.4 or 13.1 or so; however, "float
> > charging" is generally understood not to mean
> "adding
> > any charge," but to be an "in-between state" where
> the
> > charger system has determined charging (14v+) is
> no
> > longer needed, but monitoring is necessary in the
> > event charging becomes necessary.
> >
> > > What should the voltage reading on the engine
> volt
> > > gauge be while
> > > driving?
> >
> > Engine alternator charging is controlled by a
> > regulator system which adjusts both voltage (still
> > must be above 14v to charge) and amperage, which
> is
> > "current flow." The two readings are positively
> > correlated, though not necessarily, directly, in a
> one
> > to one relationship.
> >
> > Voltage and Amperage can be read from the dash
> > gauges; however, the gauges are generally reading
> > totals and not simply the portion which is
> "battery
> > charging." Therefore, depending upon the
> regulator
> > settings and total system demands for
> current/power,
> > the regulator may provide voltages from 12 through
> 18,
> > and amperages from virtually nil to the maximum
> output
> > of the alternator. For most Birds, we'd not find
> it
> > unusual to see around 14 1\2 volts and 20-30 amps.
>
> > Significantly higher or lower of either, would be
> > cause to ask "why," but not necessarily become
> > alarmed.
> >
> > > I have always thought that when driving
> > > normally, the volt
> > > gauge should read somewhere around 14.5 when the
> > > alternator is
> > > putting out properly. Last night, when driving
> home
> > > from a repair
> > > shop where several items were replaced
> (including 4
> > > new batteries),
> > > the gauge was only reading a bit above 12 when
> > > driving. Should I be
> > > concerned about my alternator?
> >
> > With the engine running, turn on all
> headlights
> > and 12V circuits and see what you find, especially
> the
> > amperage.
> > No change, and assuming the gauges are
> reasonably
> > correct, I might be questioning the regulator. If
> it
> > is found normal, then the alternator.
> >
> >
> > > Also...what is the purpose of the 'Amps' gauges?
>
> > > What do they
> > > demonstrate? My 82 FC has one on the dash and
> also
> > > one at the power
> > > switch in the step well.
> >
> > Generally, the one(s) at the step well are
> measuring
> > the amperage of the 110V circuit(s). When
> connected
> > to shore power, turn on an air conditioner
> compressor
> > and watch the amperage gauge.
> >
> >
> > > Neither gauge ever seems
> > > to move much if at
> > > all. What should these two gauges be showing
> me?
> >
> > Hopefully, some of the above may have answered
> this
> > for you, Scott.
> >
> > >
> > > Thanks
> > > Scott Forman
> > > 82 FC35RB
> > > Memphis
> >
> > John Suter
> >
> >
> >
> >
> >
> > __________________________________________
> > Yahoo! DSL – Something to write home about.
> > Just $16.99/mo. or less.
> > dsl.yahoo.com
> >
>
>
>
>
>





__________________________________
Yahoo! for Good - Make a difference this year.
http://brand.yahoo.com/cybergivingweek2005/

[Jeff Miller]

Some good information, hope you don't mind me adding my 2-cents:

The ammeter in the stepwell of the '82 ('70s through '83) is for the
12v output of the chargers to the main batteries. Usually this reads
nothing, but should read a significant output when charging low-
batteries from shore/APU power.

The ammeter in the dash of the '82 (through '83) is the charging amps
(left is discharge, right is charge) of the main battery bank from
the alternator/coach loads. You should never see it to the left with
the engine running, often around 20-30a to the right (charge) side
and rarely above that (only if batteries are significantly discharged
and there are few coach loads on).

New batteries have a greater capacity to accept a charge than do old
batteries, so you might see higher charging amps and slightly lower
voltage until they are fully charged for the first time (if not
completely charged when they were installed).

The voltmeter on the dash is the main battery voltage. As others have
mentioned, should be around 14v when the engine is running. With
everything off, this is possible, but as John mentioned the gauge is
subject to other draws in the dash etc. and drops significantly when
other loads on the dash are turned on (especially '84-'86). The
voltmeter would benefit a good deal from "home-runs", wire run
directly to the battery bank to read battery voltage and display
accurate information.

Some of the alternators need a little bump in RPM to excite the
alternator when first started, then it'll charge at idle.

- Jeff Miller
in Holland, MI


--- In WanderlodgeForum@yahoogroups.com, "Scott Forman"
<sforman@r...> wrote:
>
> I don't know a lot about electricity, so I need some help here:
>
> What should the voltage reading on the engine volt gauge be while
> driving? I have always thought that when driving normally, the
volt
> gauge should read somewhere around 14.5 when the alternator is
> putting out properly. Last night, when driving home from a repair
> shop where several items were replaced (including 4 new batteries),
> the gauge was only reading a bit above 12 when driving. Should I
be
> concerned about my alternator?
>
> Also...what is the purpose of the 'Amps' gauges? What do they
> demonstrate? My 82 FC has one on the dash and also one at the
power
> switch in the step well. Neither gauge ever seems to move much if
at
> all. What should these two gauges be showing me?
>
> Thanks
> Scott Forman
> 82 FC35RB
> Memphis
>

[erniecarpet@...]

Jeff- I don't have an ammeter in the dash on my 83 PT40. I do have one in
the rear closet by the engine preheat/ water heater switches. Kinda hard to read
that gauge while driving~ Ernie


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