Battery powered Current sink with low voltage cutoff

[Guest gregfox]

Hello all, I’m working on a project, a Battery powered Current sink with low voltage cutoff. I want to be able to connect a dummy load to a project, or run tests on batteries etc. and be able to set a low voltage cut off point.  The Sink will go up to 1.5A. 
In the attached schematic the current sink works along with the TLP222A which powers the LM324 (2mA) when the switch is turned to ON-METER-OFF (to conserve power)
In the lower right hand corner I placed a low voltage cutoff with hysteresis. The hysteresis is for battery testing, so that when the set point is reached, the circuit will not “chatter”, when the voltage drops to the set point.  The circuit works up to the output of pin 8 (IC1C). The hysteresis can be controlled by varying resistor R7.
My problem is I can’t figure out how to incorporate a panel meter that I could set (with a multi turn pot) to set the lower voltage point. I also don’t know how to turn off Q1 at the low voltage point. 
R6 does allow you to set a low voltage point, but that’s not exactly what I want.  Everything else works, I tested the unit to 1.5A and the hysteresis works from the set point up to about .5 Volt. You can disregard the IC2D as I was just fooling around with ideas.
Any help will be much appreciated.

BPCS.pdf