DaveC wrote:
Panasonic 2.4v screwdriver battery pack consists of 2x sub-C cells in
series. Pack has (+) and (-) terminals, and a 3rd terminal (charge
sense?).

This 3rd terminal connects the charge circuit to the pack's (-)
terminal through 2 diodes and 2 resistors, all in series. The diodes
are glass with a yellow band. When I hook it up to the charger, the
diodes each drop 0.535v.

What are these diodes? Germanium would drop 0.3v or less, and silicon
would drop more than this 0.5, no?

They could be silicon. What was the current? A 1N4148 drops about 0.5v at
around 150 micro-amps.

Farnell sell Schottky diodes with forward voltage drops ranging from 0.2 to
1.2V.