Some quick notes before I go outside to do things I'm supposed to be doing ...
I've said before that I consider ammeters irrelevant in vehicles produced since the early 60's. They were relevant for motors with generators and early low-amperage alternators. In those cases, the ammeters typically had a scale ranging from -30 to +30 amps, which were able show relatively small changes in generator/alternator output and battery drain.
However, with newer high-output alternators, the scale needed to be significantly expanded, to a range as great as -120 to +120. The same small output/drain that caused visible needle movement in early ammeters causes barely perceptible needle movement in newer ammeters. In these cases, an old-skool "idiot" light is actually more useful for indicating system problems.
(The 65 amp alternator that were OEM equipment in our older Dodge motorhomes are actually considered quite small by today's standards.)
Equally important, ammeters are a royal pain it the *** to wire up, regardless of size.
So, I recommend disconnecting ammeters. You can even remove them and save them to show to your great-grandchildren when you launch into way-back-when stories.
Instead, use a voltmeter to monitor the operation of your vehicle's electrical system. Most motor vehicle voltmeters have a scale ranging 8 to 18 volts, which is a granularity that makes it easy to recognize significant changes in the electrical system's operation.
(In recent years, manufacturers have started shifting from ammeters to voltmeters for OEM equipment.)
Next, voltmeters and battery condition gauges appear to be similar but are actually significant different in function and purpose.
Voltmeters are used for the same purpose as ammeters, to display the operation of a vehicle's electrical system. While they can display how much a battery is being drained, their main purpose is to indicate problems in the electrical system. A steady decrease in system voltage indicates the alternator is not producing current. Conversely, an unusually high system voltage indicates the alternator is producing too much current, potentially overcharging and cooking the battery as well as possibly frying system components.
(Detecting an overrunning alternator is difficult with an ammeter.)
Voltage regulators essentially do the same thing as voltmeters ... measuring and monitoring system voltage. Instead of displaying system voltage, voltage regulators control the alternator based on system voltage. When system voltage drops to a certain point, the voltage regulator turns on (energizes) the alternator field, causing the alternator to begin producing current. In turn, when the voltage rises to a certain point, the regulator turns off the field, causing the alternator to stop producing current.
On the other hand, battery condition gauges monitor how much a battery is being used, typically by displaying the percentage of charge remaining in the battery. (Battery condition gauges are sometimes called battery condition indicators, abbreviated as BCI.)
Unlike voltmeters, which are intended to be actively connected to the electrical system on a continuous basis, battery condition gauges are intended to be used briefly on a periodic basis, for no more than a minute at a time. The circuit for a battery condition gauge should include a momentary on-off switch because leaving the gauge continuously connected causes unnecessary battery drain.
These gauges cannot accurately display the battery's condition when the battery is being recharged, either via an alternator or battery charger. Most battery condition gauges have section of their scale that indicates the battery is being recharged/charging.
Note: To get an accurate reading of a battery's charge, a load (such as an incandescent light) should be applied, at least briefly, before pressing the gauge's momentary switch. This shifts the battery from a resting state to an active state.
So, voltmeters are appropriate for connection to an engine's electrical system while battery condition gauges are better suited to monitoring a motorhome's deep cycle ("house") battery bank.
Finally, based on my experience, the 65 amp OEM alternators in older Dodge motorhomes rarely fail. Their bearings and brushes may wear out over lengthy periods (decades?) of use but, unlike many other alternators, the diodes (in the bridge rectifier) are robust enough to still be serviceable when the bearings/brushes wear out.
Unfortunately, people tend to think about the alternator when their charging system fails. Usually, in older Mopar vehicles, it's the voltage regulator that causes the charging system problems rather than the alternator. Over the years, I've seen many, many cases were people have spent a lot of money to replace the alternator, to only find out it didn't solve their problem.
Replacement voltage regulators are relatively inexpensive while replacing an alternator usually causes a serious dent in one's budget. I've personally experienced a lazy/incompetent technician telling me the alternator was bad and had to replaced when the problem was actually a bad voltage regulator. Furthermore, I firmly believe some shops rely on people's lack of understanding to pad their profit margin by unnecessarily replacing a more expensive alternator instead of just replacing a comparatively inexpensive voltage regulator. (In addition to the cost of the components, alternators require more labor to replace than voltage regulators, further padding their profit margin.)
Enough ... got to get back to working on other things.
