The battery accepts most of the amps from the higher voltage charger.
EDIT--as mentioned by Boon Docker--the voltages as seen by the battery at its end of the wires
The solar at 14.7 will supply all the amps once the battery's voltage is higher than the WFCO's output voltage.
If the batteries are near full, then their voltage will be above WFCO's 14.4 (if it does 14.4) because of the solar's voltage, so turning on the WFCO will not show anywhere for amps or battery voltage.
When the controller gets the batts to 14.7, it will do whatever its profile says to do, such as hold it there for two hours and drop to 13.6.
I have seen on my Trimetric monitor that it can show neg amps flow when you turn off a charger keeping the batts at 14.8 and now they will go to 13.6. for the brief time it takes the voltage to fall, it shows as neg amps. Not real, perhaps a monitor thing?
so if your case is like that, if the batts are full and the solar was on the point of dropping to float and then the WFCO coming on triggered that somehow? Really stretching here!
You need to run the batts down a ways and then use both WFCO and solar to observe what happens for real. Not when the batts are full.
