Back in the 90's when solar panels where super expensive, the MPPT controller alleged that it would give 20% more amperage to the battery than a PWM controller.
While they do take in 18 volts X 10 amps and can put out 13.5 volts X 12 amps (180 and 162 watts respectively) they are not worth it anymore, because you can add an additional panel of say 140 watts for $229 that might have been spent on a controller.
SunElec.com has the $229 140 watt 12 volt panel with aluminum frame that would be ideal for a RV. Many 'frameless' panels are not easy to install on a RV roof.
Yes the MPPT controller can take in 24 volts and still charge a 12 volt battery, some can take in 150 volts maximum - so you can wire all the panels in series, and then only have 10 amps or less going into the controller, so much smaller wire can be used, and savings there.
But I like my $13 PWM controller much more than my $325 SolarBoost 50 controller - that I Bought in 1999.
Back in 1999, a 120 watt panel was $429, and getting an addition 10% was well worth it to spend that kind of money on the controller.
Yes my 415 rated watts system was normally full by sunset, even if I used 120 amp hours of power overnight.
Your RV will consume 35 AH just to run the CO and propane detectors and the refrigerator for 24 hours. This is about what one of my 120 watt panels will put out in one day.
Good luck,
Fred.
