/diy/ - Do It Yourself

Brainlet here, Ok so I have some equipment that expects battery voltage from 4.25ish at 100% and it shuts off at 3.5v.
I'm trying to replace the battery with a larger capacity one but6 it seems to work differently.
I just discharge tested the cell and it seems to be full at about the same 4.2ish volts, but at 3.5v, its only spent about 1700mah. Going all the way to 2.96v squeezes out the full 3200mah rating.
So the equipment is basically ignoring almost half the capacity of the cell.
How can I make a controller that raises the battery voltage as it discharges so it basically works within that spec?