Energizer Ultimate Lithium Unreliable?

[GTBecker]

I've been using Ultimate Lithiums in my DR-44WL. Too many times I've found that one cell suddenly, it seems, drops to ~1v and the recorder shuts down. I could excuse a rare bad cell, but this has happened five or six times over maybe six months. I no longer trust them, so I've begun using an external USB supply and will probably revert to alkalines.

Has anyone also found Energizer Ultimate Lithium AAs unreliable?

 

[GTBecker]

Answering myself, I believe I've found a likely cause of Energizer Ultimate Lithium AA apparent "failures". It may be the very sharp discharge knee. http://data.energizer.com/pdfs/l91.pdf

The cell essentially simply turns off when it is depleted, unlike alkalines which deplete slowly. This makes the power supply status indicator, the battery graphic in the upper-right of the DR-44 screen, useless; it will show full, then suddenly empty when using lithium cells.

These leads to my realization that the four cells in the recorder always need to be changed as a group; replacing a single depleted cell with a new one just sets up the next cell "failure".

 

[-mjk-]

Wow, it falls off a cliff with no warning! I'm guessing the battery indicator can't display that battery's condition accurately enough to be of any use. By the time you notice, it's too late.