An
"MPPT" Solar Charge Controller is a more complicated and expensive device, full of electronic parts. (The main "working" parts are inductors and capacitors.) You can think of a "perfect MPPT controller" as a magical box, which converts the incoming power (lower current at too-high voltage) into MORE CURRENT at the lower voltage which is optimal for the batteries, preserving nearly all of the incoming power for use by the batteries and TM appliances.
Instead of "throwing away" Solar Power which the panels generate at higher-than-battery Voltage, an MPPT Controller can send nearly all of the power into the Trailmanor - limited only by the ability of the batteries and TM to use it.
What goes on inside (you scan skip this part): When the batteries (or running appliances) can accept ALL of the Solar Panel Array output power, at the correct Voltage for the measured battery State-Of-Charge, an MPPT Solar Controller will try to keep the the Solar Panels connected continuously - absorbing all the power the panels can generate at the optimal (high) voltage of the panels. But instead of delivering "too much" Voltage into the batteries, an MPPT controller uses the input power to drive the "primary" side of one (or more) large inductors. Then, using rapidly firing switches, output power is sent from the "secondary" side of the inductors, through large capacitors, with HIGHER amounts of current.
That part of the MPPT "deal" is great. The not-so-great parts of the "deal" are:- Being full of electronic parts, MPPT controllers cost much more money.
- With so many more electronic parts, MPPT controllers are far more likely to break down.
- In performing actual power conversion, they generate considerable heat.
- In order to disipate that heat, they are built with large heatsinks. They are much larger than PWM controllers, and much less easy to mount inside a TM Trailer.
When operating in MPPT mode (and converting Voltage from "input" to "output") the conversion process generates about 6-10% waste heat. They must also have adequate ventilation, which further limits your choices for a TM installation location. The heat also degrades them over time. They slowly become less efficient, and may eventually fail. I do not know the lifespan of the models I recommend. I kon't know of any which have failed yet, but but adequate ventilation is
really important.
When the batteries (and appliances) in the TM can no longer accept as much current as the Solar Array is creating, MPPT controllers will switch into "PWM" mode acting as "PWM controllers. While doing this, they leave unneeded power on the roof, within the Solar Panels.