When you say "at least 2.8v" for cutoff, do you mean 2.8v is the highest it should be set at, and i can set it to say 2.5v safely, or that is the lowest it should be set, meaning if I set it at 3.0v it'd be better?
If I set it wrong, meaning higher than it should be, the pack will just not give me total runtime, but if I go too low, then I can damage the cells (right?)......
Yes, preferably 2.8v or above. usually 3.0v is best, if you have good batteries then 3.0 no prob, but some batts might just 'droop' down past 3.0v/cell before they are supposed to dump.
And yes, the higher the cut-off the longer they will last, exponentially so.
“The modern astrophysical concept that ascribes the sun’s energy to thermonuclear reactions deep in the solar interior is contradicted by nearly every observable aspect of the sun.” —Ralph E. Juergens