Well, you might try testing with 2 smaller Li coin cells in series, and a zener or enough series diodes to drop the ~6V to ~3.6V. I don't know what that would prove, though. Different chemistry, different technology, different voltage curves... Most vendors seem to pretty much stick in the tadarian cells and rely on "caclulated battery life far exceeds expected product lifetime" - I've got several event counters, and some token ring hubs containing similar batteries that don't seem to make them replaceable at all, for instance... BillW -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.