If you have the 68100, it has a button on the front to select bulk
http://www.bestconverter.com/assets/images/WFCO/6800/6800manual.pdfIf not, then another charger will not hurt anything, but the battery will not get anything from the WFCO after its voltage goes past the WFCO's voltage. After that, the only amps you will get is from the other charger that does go to 14.x volts.
I have a 100amp PowerMax that also has PF correction, and it does bulk at 14.8v. I run that and my VEC1093DBD together (also 14.8) and get 140 amps constant (no tapering) until battery voltage reaches 14.8 when tapering starts in the absorption stage.
You do need a generator can power all the chargers at once though. My Honda 3000 can do a total of 130 amps of non-PF corrected Vector chargers, or it can do 150 amps of the 100 PF corrected plus 50 more amps of Vectors.
