The earlier PowerMax converters worked the same as WFCO for going into boost with that 13.2 thing. IMO it is more clear to explain it this way:
Any time you first start a charger on a battery, the battery voltage "spikes" from 12.x to 13.x and then the battery voltage rises from there to whatever the charger's Vabs is.
For WFCO to go into boost, that initial spike must stay below 13.2 *as seen at the WFCO* That means the battery has to be low or the spike will go over 13.2 and no boost.
How low does the battery have to be so it spikes below 13.2? Now you throw in the wiring issue where more wiring R to the battery makes the spike go higher, so it is harder to keep the spike under 13.2.
If you have low R wiring and the battery is low (a bit under 50%--12.1v-- can work if the wiring R is low) you can get boost. My older PowerMax that was a sort of WFCO clone did boost ok in that case, but you had to get the batt good and low. 51% SOC no boost, 49% SOC yes in my case with low R wiring to battery. (two feet of fat wire in my case)
EDIT I left out an important thing that smk mentions often. The spike also depends on the charging rate. (charging amps wrt bank AH capacity) If the charging rate is higher you get more spike, so if you hit a single 24 with 55amps you get a spike over 13.2 right there. smk is always advising to use a lower charging rate, but then that is no help when on generator time. ok for shore power.
