I'm building the basic 400 watt system that will have three 100 AH SOK lithium batteries. I watched the Long Long Honeymoon solar install video where they installed a stand alone Renogy DC to DC charger and a separate Victron MPPT controller. I'm looking at the suggested MPPT controllers you have listed but it doesn't include the new 50 amp Renogy DC to DC charger with MPPT that lists for $299.99. As I understand it, when the vehicle is running the charger will pull any available power up to 25 amps from the solar panels and limit the alternator to 25 amps. Reducing the alternator output should also improve fuel efficiency because the engine won't have to work as hard. But if the panels are turned off, the alternator can provide 50 amps.
Question 1: Will the MPPT controller work if the vehicle is turned off and the panels are turned on?
Question 2: Is there an advantage to having a separate MPPT controller if I buy the Renogy DC to DC charger with MPPT?
Question 3: The Renolgy DC to DC chargers require a separate wire connected to the ignition circuit if the tow vehicle is equipped with a smart alternator. I can see where there may be times when you want to turn the charger off to conserve engine power. Some installs show connecting the wire to a fuse that is only powered when the ignition is turned on. In the "All About RV's" video the wire is connected so it can be turned on manually with head light switch. But the video shows that you can turn it off by turning the headlight switch to "Auto". Wouldn't the charger turn back on when the headlights automatically turn on? In an "RV with Tito" video he installed a separate toggle switch. Is this a better solution?
Question 1: Will the MPPT controller work if the vehicle is turned off and the panels are turned on?
Question 2: Is there an advantage to having a separate MPPT controller if I buy the Renogy DC to DC charger with MPPT?
Question 3: The Renolgy DC to DC chargers require a separate wire connected to the ignition circuit if the tow vehicle is equipped with a smart alternator. I can see where there may be times when you want to turn the charger off to conserve engine power. Some installs show connecting the wire to a fuse that is only powered when the ignition is turned on. In the "All About RV's" video the wire is connected so it can be turned on manually with head light switch. But the video shows that you can turn it off by turning the headlight switch to "Auto". Wouldn't the charger turn back on when the headlights automatically turn on? In an "RV with Tito" video he installed a separate toggle switch. Is this a better solution?