now that panel prices have come down, and efficiency up so panels are less expensive and smaller for many cases PWM makes sense given the price.
There is at least one case I often encounter where MPPT and series connected panels pays off vs. PWM or parallel MPPT
I have 3 175ish W portable panels. In a few cases when we camp the only location that gives reasonable sunshine is located 100-150 ft from the trailer. For cabling I made up a bunch of cables using 30A RV cables with anderson connectors and paralling the ground with on of the other two wires. So basically I have a cable with one wire #8 and one wire #10. Now stuff 30ish+ amps down that cable with 3 panels in parallel vs 10A in series with an MPPT controller at the batteries. MPPT wins in the series with about a 10% current gain vs parallel.
As far as my experience with MPPT vs PWM, the experiments I did for comparison did show an advantage to MPPT even with short cables, but not as high as one might think. Many MPPT controllers are most efficient with series connected panels with voltage near the max rated for the controller and least efficient with 12V parallel connected panels. That was born out in my experiments with the 12V parallel connected panels have more output than my PWM controller but on the order of 5%. while the series connected setup with 3 series 12V panels had better performance. I have the data archived somewhere.
In any event, IMHO with todays prices if you have room spending the money on and extra panel and PWM controller will get you more AMPS than spending the money on a MPPT controller.
