Voltage Readings

[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
>