Lithium (coin cell) backup battery

[Liam Hays]

(11-20-2021 02:53 AM)SEasterling Wrote:  Does anyone know the first graphing calculator model in which a lithium ion backup battery was used? I thought I saw it in a 48G+, but maybe I was seeing things through keto brain fog. Thanks!

If you mean a lithium coin cell, like Maximilian Hohmann suggested, the 48G+ was definitely not the first to use one. None of the 48 series use any backup battery, instead, the memory is held by a capacitor that is only discharged when the main AAAs are removed.

That said, I am reasonably sure that the 49 series and the 50 use a backup. Don't quote me on that, though, as I don't own them.