You might want to try some lithium AA cells. They start out around 1.65V. They are MUCH less prone to leakage than any "alkaleak" battery and have a very long shelf-life (i.e. good for low drain memory backups). As always, when adding a backup battery to a GPS, verify that the battery connection pin is not trying to charge an external super-cap or nicad.
I change the batteries every 2 years not so much for voltage as concern for
leakage. Then use the old battery in my wireless mouse.
Mark wrote:
You might want to try some lithium AA cells. They start out around 1.65V. They are MUCH less prone to leakage than any "alkaleak" battery and have a very long shelf-life (i.e. good for low drain memory backups).
Not only that, they have considerably greater energy density and a much
flatter discharge curve than alkalines, and are better at high discharge
rates as well. I haven't used alkaline AA, AAA, or 9-volt batteries for
more than 10 years now. One of the major mfrs at one time made lithium
"C" cells. I still have a stash of them in cold storage, but I haven't
seen them for sale for some time. I looked for lithium "D" cells, but
never found any.
NB: We're (at least, I'm) talking about lithium primary batteries,
not rechargeable lithium batteries. The usual chemistry is LiFeS2. For
data, see:
http://data.energizer.com/PDFs/lithiuml91l92_appman.pdf
Best regards,
Charles