overcharging issues in MPPT solar controller with NO output leads
Unless it measures current for Batt. separate from load there is no provision to detect loading during CC, CV, floating and cutoff control if Lithium.  Thus it is not intended to be loaded during CV so it goes forever if the load is &gt; cutoff which is usually 5 % to 10% of CC.
BUT for SLA and car batteries you only have CV with possibly thermal control of CV and floating for SLA.
Show all datasheets of every box.  In short, a smart controller has 2 control functions, MPPT for source and another for output regulation with 2 outputs; Bat and load.   Yours only has 1 output not 2.  So float voltage is the safest.

lead Acid batteries can be left at 14.2 if solar power is available, then load sensing is your option with an
ammeter