HP21 bacteries


I would like to know the characteristics of rechargeable bactery (voltage and intensity) of HP-21, because I have it damaged. In HP museuum i cannot find this information
Thank you, Fabio Bertella


Very easy: 2 cells CD-NI 1,2V 600mA.
But works great with to AA Alkaline battery (2x1,5v)
good luck !!
Philippe from France


Hi Fabio,
look at http://www.hpmuseum.org/batts/battery.htm. Very useful information IMHO.



I use 1800 maH AA sized NiMH cells in my woodstock series machines... they give three times the run time of the standard 600 maH NiCad cells (you charge them for three times as long).


David - do you use the standard HP charger?


Yes, I use the standard HP charger. As long as the charger is a slow charge system, NiMH cells will directly replace NiCad cells... it just takes propotionally longer to charge them fully.

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