How fast will my USB-C and 12 V inputs charge my LightSaver Max?
The USB power limit is not based on the current handling capability of the batteries or the battery charger circuit. The Max does not operate a USB-C power delivery protocol, so it will only ever draw 5V from a type C power supply. The standard USB-C cable current carry capability is 3A, so the max is set up to draw the maximum amount of power from a given USB adapter, but no greater than the 3A that a standard USB-C cable is capable of handling.
For the 12V input, during the design process, a choice was made to limit the current into the batteries to no more than 4A. That means that depending on the state of the battery (6 - 8.4V) the current draw when charging the batteries from a 12V power supply is limited to 2 - 2.75A.
* While the yellow portion of the LightSaver Max's charging gauge only takes up 4 led lights, it holds nearly 70% of the battery.