Call the people at BestConverter.com and discuss it with them. Be prepared to give them the EXACT model of the converter you have, including the amperage of it (should be on the info sticker you will find after removing the cover).
They will almost certainly recommend a Progressive Dynamics unit, which has multiple levels of voltage for charging your batteries and is much easier on the batteries than the Parallax units.
I removed my 45 amp Parallax and installed the Progressive Dynamics PD4645 upgrade kit that includes the converter already mounted in a new metal shell. Just the wires to swap over on it and slide it in.
Charles
http://www.bestconverter.com/
