How does a charging system work 2004 kountry star

Two thoughts: When you say Discharge: DO you mean house or chassis.

HOUSE Depending on your battery control center, it may take a while epically on a Diesel, for the chassis batteries to come up to the point where the isolator connects them up... Some of them are voltage controlled.

Chassis: It is no longer August, some Diesel engines have heaters (Glow plugs) that can suck major amperage for a short period of time.

On your unit, the chassis alt charging system is DIRECT to the chassis batteries and does not go thru any Newmar installed equipment. You do have a Bi charge (BIRD) relay system, but that is for the Coach batteries charging from the chassis system. This BIRD has nothing to do with the chassis system charging the chassis batteries. Now, if you have a problem(short or open in the Coach battery charging system, that "may" affect the Alternator output, but not likely. There IS a voltage regulator on all Diesel Chassis engine charging systems, but it is Frtliner installed. Either in the Alternator or close too it. Sometimes on Diesel systems, the lower voltage for a few minutes is NORMAL as the engine glow plugs may still be activated for a few minutes. If the batteries are old/weak, then the lower voltage may be a sign of that, not your charging system. Start the Genset, and let the coach batteries be charging from your Inverter or Converter which ever you have. Then start the chassis engine and see if you get the same voltage drop and rise. Doug

I assume you are discussing the charging of your chassis starting batteries.

Start the engine, rev it to 1000 rpm and take a reading with your voltmeter at the battery terminal. It should be about 13.6 dcv as the alternator is replacing the charge used in starting the engine.

If not, then you have a problem between the battery and the alternator.

Loose connections or dirty connections could be the problem and the cheapest to fix.

My rig has a battery isolator that splits the alternator charge between the chassis battery and the house battery.

Otherwise the starter and the alternator are the only other connections I am aware of.