You are correct on the POS parallax unit. My trailer had on older one in it when I got the trailer, and when it started acting up, I replaced the "guts" with their "improved" unit. Still a POS. Generally it would only work reliably when plugged into shore power. Any time we were running on the generator it would be dicey whether it would decide to charge or not, no rhyme or reason at all.
So after reading up on the internet, the general consensus out there it that the parallax unit is in fact a POS, which I had already determined for myself, twice.
I called up Best Convertor
BestConverter - Converters, Inverters, Electrical Supplies, Electronics and ordered up a Progressive Dynamics upgrade unit
4600 series Upgrade Kits to replace the "guts" yet again. Time being short as always, I tossed the box in the trailer to install when I got a chance. Well, this week after being on the generator for 4 days, and the old POS unit acting up after the 3rd day, I went ahead and put in the Progressive Dynamics unit. Easy conversion, and worked perfectly after. My lights have never been this bright, and the batteries have never had this good of a charge.
I also added the charge wizard pendant. The upgrade unit has a charge wizard build into the circuit board, but you have to open up the cover to see what it is up to. Adding the pendant just lets me stick it on the wall in easy view. Best convertor has a document on their website as to how to wire up the remote to work.
They also suggested the surge protector, which I bought at the same time.
If you have a parallax, just pitch it in the trash now and save headaches later.