MPPT will always gather more power.
...
My god!
Repeating so much wrong statements... from a moderator here!
I did already explain that that such general statements just lack veracity. One should consider things with a bit more differentiation.
No, MPPT will not ALWAYS gather more power!
(I am speaking about off grid situations only. On grid, there is no discussion MPPT is a must.)
Off-grid, there here are two situations, where MPPT just gathers
less power than a PWM controller.
Using a panel of the same nominal voltage than the battery,
(e.g. a 12V lead acid battery with typical 18Vmp panel (<100W) or a 24V acid battery with typical 36Vmp panel)
and
a) the panel gets very hot (under tropical conditions)
b) the solar irradiance it is very low (under 50W/m²)
under these conditions the panel's Vmp (which is not a constant) comes very close to the battery voltage and a MPPT controller will not be able to handle efficiently the tiny voltage difference -> a PWM with just harvest more.
Finally, there is a reason, why panels are designed that way (Vmp18 or 36V) :
They were historically optimised for PWM usage with standard batteries.
MPPT needs a
good voltage difference, else they may operate, yes. But they will operate
miserably!
The rule of thumb is to use MPPT with 36Vmp panels for a 12 V battery and 72V panels (or panel combination) for a 24V battery.
Do not use MPPT with matching nominal voltage panels! (18Vmp with a 12V battery or 36Vmp with a 24V battery).
Then there is also one common situation where MPPT gathers more power than a PWM controller,
but it just doesn't matter.
If you are in a sunny situation and your battery is full at 11:00 anyway.
After that you will just be throwing energy away, so
it just does not matter if you got 100% at 11:00 or at 12:00.
Last but not least, PWM controllers have less own consumption than MPPT controllers, on designing low-power solar powered systems, it may matter.
PWM can't be over-paneled.
...
Of course you can! it is even recommended!
The only caveat is to match the nominal voltages.