Recharging batteries in a HP75 Pod


Hello, I have a battery pack of unknown condition which came with my HP75+Pod.

I wonder if there might be a problem if I try to recharge it inside the dedicated slot in the Pod without knowing if the pack is good.

Can I try this or do I have to ensure the pack is good first ? I have only a multimeter at hand at the moment and no suitable external charger.

Thanks for sharing your wisdom.


If you have an original HP pack, it is over 15 years old and is bad. Attempting to charge it should not cause any damage though.


Thank you !

A sticker inside the pod's battery door says that to work correctly the machine needs a working pack in place. Do you think I must be sure that the pack works before powering the machine on ?

I guess this just means that you must have a good pack in place if you run the machine off mains power.

Can I put the pack into my HP55 to test its status ?

Thanks again.



I have a battery pack for the HP55 that I have already used in an HP75D. For as long as I can think of it, there is no issue using a battery pack in one of them that had been used (or charged) in the other.

In time: the HP55 original charger is able to both 1) supply the internal circuits of the calculator with regulated voltage and 2) charge the the batteries with a proper voltage value, at the same time. This is why it uses a connector with three connecting points. If you suspect the battery pack is bad and you decide to use it in the HP55 with the charger in order to test it, the deffective pack will not be charged and chances are that the calculator works fine, anyway. I'd try to test the battery pack outside the calculator; I do not think it´s worth risking an HP55 for testing purposes.


Luiz (Brazil)

Possibly Related Threads…
Thread Author Replies Views Last Post
  HP Prime recharging bluesun08 4 1,839 10-24-2013, 06:08 PM
Last Post: Mike Powell
  Recharging original batteries in HP 45, 65 and 25 Michae Altmann 1 1,238 03-05-2013, 12:21 AM
Last Post: DavidShenk
  Half & Half Recharging Matt Agajanian 21 4,856 04-10-2012, 01:31 PM
Last Post: M. Joury
  HP75 Plug-Module Simulator Manual pdf Jake Schwartz 2 1,345 04-23-2011, 07:59 PM
Last Post: Paul Berger (Canada)
  HP75 Accessories as new - any value or should I just use them? Tony de Groot 0 710 07-03-2009, 09:28 AM
Last Post: Tony de Groot
  HP-97S Pod Schematic Katie Wasserman 7 2,251 06-29-2009, 09:47 PM
Last Post: Thomas Chrapkiewicz
  HP75 HPIL IO Tony de Groot 6 1,876 04-25-2009, 05:02 AM
Last Post: Tony de Groot
  MCLEX for HP75 Help !!!!!!! gileno 0 680 02-26-2007, 04:38 PM
Last Post: gileno
  OT - recharging NiCad in a Commodore SR4190 GE 12 3,130 11-10-2006, 04:11 AM
Last Post: GE
  HP-75D POD Diagnostic 5061-7248 John Pierce 0 664 06-26-2006, 08:08 PM
Last Post: John Pierce

Forum Jump: