[Answered] HP-82120A battery pack

[Dieter]

(11-12-2018 10:02 AM)grsbanks Wrote:  Does anyone have a reference for the Ni-Cad cells in the HP-82120A battery back for HP-41C?

Originally the pack had four 1/2 N sized NiCds. These are no longer available. Refurbishing a 82120A today usually is done with 1/3 AAA cells, and NiMH instead of NiCd. Here the typical capacity is 170 mAh which is about twice the original 1/2 N capacity. The circuit board inside the 82120A sets the charging current to about 15 mA which is just fine for a 12-15 hour charge if the battery is completely empty (!).

This topic has been discussed several times both here and elsewhere, so you should find instructions and tips on how to do the conversion.

Dieter