How often do you usually use your charger unit while out camping? At what battery level do you think it's best to start the recharge? Where is the negative cable from your charger unit connected?
The negative battery cable from the charger is connected to one of the two negative battery terminals. In the picture, the battery tray happened to be partially open, not fully open, so that connection is not in view.
About your other questions. Keep in-mind we have the earlier 2000 watt Tripp-Lite inverter and two 12v batteries, so what I share next might be different for you.
I don't use the battery meter above the stove, only the Tripp-lite meter below. But even that one is not precise enough for me. Actually we have to watch that meter closely because once the yellow light alone goes on, it's time for charging. If I wait much longer, we could have dead batteries by morning, especially if running the furnace during the night. With dead batteries it gets serious because the fridge is dead.
I have learned to shut off the inverter using the switch on the inverter itself, when we don't need inverted 110v. This because the inverter uses 12 amp hours whether you use 110v or not so shutting it down saves a lot of battery reserves. If you want to shut the inverter by the entry door, that kills 12v to everything including the fridge so that's not a good plan.
Because we most exclusively camp without hookups, and we tow a vehicle, the motor home can sit for a number of days at a time without being driven. Then we become completely dependent on charging the house batteries off the generator. Without our 4/10/20/40 amp charger, the generator would have to run for over 24 hours before our batteries would get fully charged after a complete draining. And we really don't like running the generator because of the noise, so I try to keep the run times as short as possible.
With well charged batteries, we use the inverter generously for watching TV, making coffee, and charging electronics. When we see an upcoming power shortage, we'll watch TV in bed off the lower power TV set, and make coffee with the generator running for just long enough. On a weekend getaway without hookups, we don't give the batteries any thought because the trip starts out with a full charge. But when out for 3 weeks, we have to watch our power because a full charge is rarely accomplished. Sometimes we'll run the generator for an hour per day to keep up with power needs, using my own charger on the 40 amp setting. Without my own charger, I would have to run the Ford V10 engine because that is the next best charger.....maybe even the best charger at a high idle condition.....that would be where a stick could be used between the driver seat and gas pedal. But I find using my own charger working better for us.
Because most RVers drive to places where there are hookups, they rarely find themselves in our predicament. Even those who don't hook up but drive their rig everywhere (no tow vehicle) have no such concerns because driving the rig takes care of the batteries nicely.
Sorry for the long read.