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Load Resistor Causing Unwanted Voltage Shift on Comparator
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Pentoad:
So I've been working on my cell balancer design and there's always been a strange problem with it where RL is acting like some kind of weird hysteresis. LED 2 is used to indicate whether the mosfet is conducting or not.  If I disconnect the load resistor and adjust the trimmer until the LED comes on and then connect the load resistor, the LED goes off and doesn't come back on unless I increase the supply voltage or adjust the trimmer. K1 4 and B+ are all connected together and are at the same voltage. I replaced the hysteresis resistor with a capacitor and this prevents the comparator switching at very high frequency causing the mosfet to overheat. It now switches at around 20hz

So I did some tests by only adjusting the supply voltage measured at B+ / K1 4.
With RL disconnected, the LED starts flickering at 3.878v and is fully on at 3.882v
With RL connected, the LED wouldn't start flickering until the supply voltage went to 3.974v

I don't understand how the presence of this load resistor on the mosfet is affecting the voltage at which the comparators are triggering because it's not directly connected to their inputs. I even measured the inputs and the resistor isn't affecting their voltage. The whole thing is set up on a breadboard currently



amspire:
Try measuring the switching voltage using the B- leg of R22 as the negative reference, not the B- connection on the battery. See if it now flickers at 3.88V with the load resistor. You may need to take the B- lead from R22 back to the battery as a separate lead, if other circuit resistances are not low enough in your circuit hardware.
Pentoad:
With the resistor disconnected I get a solid 1.2755v at the output of the potentiometer. When I connect the load resistor, the LED goes out and the voltage at the potentiometer ripples around randomly within 100mv. It doesn't affect the voltage at B- at all.
SiliconWizard:
Is K1 4 connected to B+ directly? Did you look at the difference B+ - B- ? (Sorry if I state the obvious, but if the reference voltage for your potentiometer-based adjustment is the battery voltage and the battery voltage drops, will your circuit behave as expected?)
Pentoad:
The reference is generated by a LM4041AILT-1.2. In my test setup K1 4 is directly connected to B+. Connecting or disconnecting the resistor has no effect on the reference voltage.

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