Voltage Readings

[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
>
>
>
>
>
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