WFCO needs to have voltage sag below 13.2 volts during the initial charging AT THE CONVERTER TERMINALS.
Your battery can be resting at 11 volts and WFCO voltage pops to 13.25 at the converter and no boost.
The only easy way I know to get boost consistently is to hit the battery with 160 amp load using an inverter powering the microwave. 20 seconds is fine and away it goes. Still need fat wire connection. The smaller the WFCO the easier to get the voltage to sag below 13.2 volts.
Put a voltmeter direct on the converter output before you power it up then monitor performance.
