The challenges:
In order for an inverter/charger to start charging lithium batteries (initiate a bulk charge) a need for that charge has to be detected. With Magnum inverter/chargers, this happens when the battery voltage dips below a default value of 12.8V. By putting the Magnum in Silent mode, you can adjust this rebulk to voltage to 13.1V, but lithium batteries have to be deeply discharged to get down to 13.1V. This voltage can sometimes correspond to a state of charge of about 20%. Victron inverter/chargers have an automatic rebulk that happens on a timer every couple of days.