> my new GPSMAP 60CSx does not like Lithium batteries, it actually shuts itself down.

Eeek! I have one of those (without the S). I just went and tested it and it has the same issue. I tried putting the NiMh back in and changing the battery type in the set-up screen to Li-Ion (sic - it certainly won't run on Li-ion rechargeables and apparently this option is the one which is supposed to work with Lithium) and it still didn't work.

Interestingly, my older GPSMap 60 does work with Lithium. I suspect I tested it when I got and and tried it again just now. I hadn't retested the newer device until I saw your post. I had been carrying a pair of Lithiums as my emergency backup for the GPS unit, thinking they would work.

Thanks for the warning. I've just sent ETS a $10 donation via their JustGive link, because this may have saved me some severe embarrassment.