to add to the WFCO operation.
WFCO stuffs high current into the battery at startup and looks at the voltage AT the charger. if it is above about 13.2V it goes to bulk mode. Therein lies the major issues (a) the voltage at the battery terminals PLUS the voltage drop along the line must be low enough to go below the threshold.
(b) stuffing current in then looking at voltage is the opposite of what PD and others do, which is to look at battery voltage make a decision, then act and track.
There are tricks with the WFCO, like running a microwave on an inverter, especially with GC2 batteries to get the voltage enough under the threshold to get the WFCO into bulk mode and have it stay there.
easier is to toss the WFCO and go with a PD or other good drop in.
Can't count the times we've been boondocking and people ask how we can only run the genny an hour or so, while they need hours and still have not much battery. I grab my clamp on amp meter and show then the WFCO is only giving them 10-15A charging current and 13.6V not the 50A claimed.