So...I discovered this while checking that my battery was still in balance:
Wasn't on very tight. At least not tight enough to compress the bus bar down flat against the cell's terminal. Looks like most of the current was flowing through the bolt, and some passing through the aluminum screw-on collar (giant nut) for the terminal.
How much current can one little bolt handle for how long?
Maybe that's why I was getting more of a voltage drop than I had originally expected.
Resistance is not futile, apparently.
I've changed out the bolt, leveled out the bus bar & hand checked/re-tightened every terminal's bolt.
I'm at the beginning stages of the second half of the battery pack. Currently have the cells charging again in parallel. Had to borrow a couple of bus bars (though I still have more than I paid for!) from them, so 2 or 3 cells weren't in
perfect balance with the rest...though it was only barely measurable, in the thousandths of a volt. Maybe I'm being a bit too paranoid?
