In my previous 5er I removed the stand alone wfco 55 amp converter and connected it direct to two 6v GC2's with 18" of #6 wire. First I drew the bank down to the low 11 volts at rest level I think it was 11.4. The wfco never showed over 13.2 volts, or was it 13.4. Any way it was low 13's no way it went into the 14's.
Progressive Dynamics has a replacement converter shelf that will go right into your wfco power center. Make sure you get the pendant.
http://www.progressivedyn.com/pd4600_converter_replacement.html
All kinds of videos detailing install.
https://www.youtube.com/results?search_query=progressive+dynamics+pd4655+installation
- Jeff