You are correct in saying that a Lithium cell could leak and or explode,
if attempts are made to charge such a cell. Perhaps I should have mentioned
this in my posting. If I were to use a lithium cell to replace the nicad
3.6 volt cell (that is the actual voltage), then I would defeat the charging
circuit. It would not be required for the lithium cell. Sorry for not making
that point in my original posting.
Fran KM1Z