Check here to see the various types if you missed on that. PM3s and 4s are deck mount. They do make a lower portion only version for various amp sizes and even a full power centre too with a 60 amper in it.
http://www.bestconverter.com/The PM3s at least the earlier version were like a WFCO for going into "boost" at 14.4 That is, the batteries have to be down to just under 50% or it will kick off at 13.6. This is no problem if you are on shore power of course.
The PM4s like Randy sells are different in that they will go into boost first no matter what and if the batts are already up, it drops to 13.6 after a few minutes (15 min ISTR) similar to the way Iota does it. So that is a much better match for generator charging as when off grid unless you only run the gen when batts are down to 11.9 so the PM3 will go into boost for sure (iffy at 12.1)
The PM3s cost less (boatand rv)than the newer version PM4s, so you have to know what features are worth it for your situation.
