Hi,
The Epsolar Tracer solar mppt charge controller has a menu option
to disable the temparature compensation.
(I do not use it in my car
)
Maybe yours has that option too?
I switched temp compensation off because I wanted to automatically switch on
a load at 14.5V I was kinda difficult to design an electronic circuit
vith the voltage changing a little ever so often (measured it).
Just to give you an idea.