Originally Posted by pgandw
Not really. Any multi-stage charger attempts to read the battery voltage to determine what voltage to supply to the battery. Basically, high voltage charger wins because the other chargers read the high voltage charger and shut down or go into trickle mode. You have no way of knowing what charger is doing what unless there is an external indicator of some kind because they are all tied to the battery.
Solar charge controllers are normally set up to be the highest voltage charger when there is sufficient voltage provided by the solar panels so that you take advantage of solar power. When available solar panel voltage drops (nightfall or shade), the other charger(s) will sense the lower battery voltage, and step up their charge.
Sorry Fred. Yes, really. I disagree with your first paragraph. The high voltage charger will not raise voltage and drive the others into float mode.
What will determine which charger goes into bulk mode is its voltage setting that triggers bulk mode. If one charger goes into bulk mode before the others as the battery is used and voltage drops, it might indeed go into bulk mode alone and do the heavy lifting, proceeding through its three stages while the others remain in float mode. But, the OP asked if he needed to disconnect the solar when connecting a generator or grid. The answer is no.
More detail: Op's modest solar is very unlikely to take control and keep other chargers from helping. If it does, the battery is already near full charge and above the bulk kick-in voltage setting of the other chargers (usually about 12.6V). And if it does, fine. More typically the generator will be started because the battery is low or getting low and voltage will be low enough for the house converter to jump in and work in tandem with the solar to charge the battery. The two (or more) chargers will proceed through the three charge stages together very nicely.
If the RV is on utility power, a small solar system as the OP has is not going to save much money even if it provides maximum output. And, if the OP starts a generator, and it causes the solar output to drop some (only may happen in stage 3; float mode) the impact on fuel use will be miniscule. And, of course, the OP would not start the generator until the sun is waning and the solar has not done enough.
The bottom line is the multiple chargers will do their thing and trying to optimize things is not worthwhile. Monitoring is not necessary.
The next above said, battery system monitoring is good to have for other reasons. Having a monitor and keeping an eye on things will reduce the risk of damaging a battery or having to start a generator at 11:00 pm because the propane heater fan will not spin up.