https://imgur.com/gallery/HnqdwHcI have not hooked it up yet but this looks like something that can be improved upon relatively easily.
Needs much larger input capacitors and it should be relatively easy to parallel more mosfets and then tweak the shunt resistors to get more current out of it.
The 100 volt maximum input will work fine with the three solar panels i have in series. (30v oc each, 8 amps short circuit, 25v mpp at 7 amps)
Im not sure what it has reverse polarity protection on. It appears to have 2 mosfets in parallel on the output. (Probably over discharge protection for the battery), (it has separate load and battery terminal blocks)
The input appears to go through 2 mosfets in parallel (which would make sense for a 20 amp buck converter) with a third to220 for the diode.