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Battery pack of HP 25 calculator
07-03-2018, 01:49 PM
Post: #1
Battery pack of HP 25 calculator
Good evening,
Since long time a have an HP 25 calculator. It is years it is no more in use, just because it was no more possible to get the Woodstock battery pack (at least in Italy).
So I had got a new HP calculator with botton batteries.

I would like to re use my HP 25.
As I still have the last battery pack I used, I'm now thinking to cut the battery container and substitute the two with new NiCd (?), if I'll get them in the market.

The first problem is to know exactely the voltage each battery stylus should grant. The HP25 User Manual is saying nothing.
The Museum reports: "To reduce the size and weight, the 20 series used two rechargeable cells instead of the previous three. This 2.5 volt supply was converted to 4 volts to operate the display."
So I ask if anybody can help me on two questions:
1) I wonder if the total pack should supply 4 volts, 2 volts each. A strange value for today's standards, I presume. Is it correct ?
2) Which should be a satisfactory mAh capabilitiy both for the calculator and the recharger ?

Thank you in advance
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Battery pack of HP 25 calculator - Carlo Meletti - 07-03-2018 01:49 PM

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