Read it and weep. No converter will do this. Some chargers will.
http://pdf.wholesalesolar.com/battery-folder/charging_instruction_2011_2.pdfI have been using PM converters as chargers for a few years now. We are off grid at a seasonal site from mid-April to end Sep. What lets us do that is solar plus using the gen and charger as required when it is cloudy and solar can't keep up.
I modified my 100amper so instead of dropping to 13.6 as soon as it gets the batts to 14.6, it stays at 14.6. So it now is no good as a converter, but the trailer already has a perfectly good converter for when on shore power.
I did have some trouble with the 100amper blowing its in-rush thermistor but it turned out that was due to using it as a stand alone charger. I had rigged a set of heavy jumper cable clamps to it for connecting and it turns out you need to clamp on first, then start the unit. If that conks out your gen because it is not warmed up and you restart the PM right away after the gen is restarted, the PM will blow that thermistor from not waiting long enough for it to cool--maybe half an hour.
Anyway, once that all got sorted out, I really like my modified PM100 for a fast charger followed by solar the rest of the day. The solar controller is now the key to success where it can get the batts to 15v or so, which meets the battery spec.
If all you have when off grid is that un-modified PM75 you are always going to be in trouble. I recommend you leave it un-modified and get a VEC1093DBD to use as well. After the 75amper drops to 13.6, disconnect that and clamp on your 40amper VEC and let it finish the job. It goes to 14.8 ( and that is temp comp!)and stays there. If you stay out more than a couple weeks doing 50-90s, then you absolutely need solar, since after several 50-90s in a row your bank will have lost a bunch of capacity and may not even get you through one night anymore. Then you are stuck until you can get shore power and a few days to do a "recovery episode" so you can go off-grid again.
