According to the Model X Owners Manual,
available online here, the vehicle's 12V power sockets are "suitable for accessories requiring up to 11A continuous draw (15 A peak)".
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So, the 2.6A that we see being drawn in the photo I posted earlier is well within the capacity of the Model X vehicle's 12V accessory power system. In addition, the CUZEC male power adapter that I used to provide power to the charge controller from the Model X rear power plug is fused and comes with a 15A fuse.
The primary reason I purchased a charge controller was to ensure that the lead acid battery was properly managed during its charging life-cycle to extend its useful battery life. There is a great deal of information about charging lead acid batteries online, but if you are interested in learning more about this topic, I suggest a quick read of
this article and especially the graph in Figure 2 --- the charge controller essentially implements the graph for the sealed lead acid battery taking into account its current charge state (voltage), ambient temperature, etc.