OK to use 2 CR123 cells in an HP41C ?


The Cr123 are nominal 3 volts, but I believe put out a bit more when new. Is it OK to use 2 in series in an HP41C ?


Should be fine. Alkalines give nearly 1.6V each (3.2V for a pair, for comparison) when brand new. A set of alkalines lasts at least a couple of years in my 41cx, but they are getting expensive at nearly $5 US for four.


A set of alkalines lasts at least a couple of years in my 41cx, but they are getting expensive at nearly $5 US for four.


AA alkalines are used in lots of stuff and they store well. I buy them at Costco in a box of 48 for under $15 (house brand). Duracells are about twice as much, but 24 for $15 is 1/2 your price!

Of course, a great alternative is the sanyo eneloop (long shelf life, rechargable NiMH). Costco has an assortment with charger for $25... About the same price as elsewhere for the cells alone.



Neither Costco alkalines nor Sanyo Eneloops come in size N unfortunately. I've only ever seen N size from Duracell and Energizer.



In addition to Duracell and Eveready, Panasonic makes both carbon and alkaline N/E90's, Varta makes alkalines. I'm sure there are more...

FWIW, Sanyo still makes N 190mah ni-cds.

Just Google N-190N for lots of fun.

Edited: 21 Jan 2008, 8:16 p.m.


CR123's will not fit into the 41's battery holder, they are too wide.

CR123: 16 x 32mm

N/E90: 11.3 x 32mm (nominal 12 x 32)

Overlooking the size problem, you would need to create two dummy cells to complete the circuit. That is of course if you are using the standard battery tray.

Beware the A23 cells, they fit but they are 12 volts. Inserting four of those into your 41 will cause it to emit the factory installed smoke. The result is not pretty.

AA cells? Who mentioned AA cells? If we don't care about size, why not use a 6 volt lantern battery? That will run a 41 until the battery decomposes...

Edited: 21 Jan 2008, 8:20 p.m.


Ah, you're right. I was thinking of of a different one, and thought the OP was thinking of modifyting the battery holder. I've seen AA alkalines as low as about $.25/ea, but that doesn't help in this case. Fortunately N cells seem easier to find than AAAA.


A while ago someone posted this here. It's for mimh N cells and a charger for them. I haven't tried them because i already have nicads and a charger along with a custom drainer that Katie told me how to build.


This company in Canada, bbmbattery sells the NiMh GP-50NH1A for $3.50, or $33 for ten.


Alkaline N cells are not that difficult to find. I would simply use them. The 41 consumes little power so there is no need for rechargable unless you use the card reader or the wand.

Possibly Related Threads...
Thread Author Replies Views Last Post
  How to check / repair a HP 82106A module for HP41C calculator ? Eduardo Mingo 13 2,810 01-07-2013, 11:05 AM
Last Post: Diego Diaz
  A simple question about the HP41C or HP41CV Antoine M. Couëtte 6 1,915 12-16-2012, 04:06 AM
Last Post: Antoine M. Couëtte
  HP41C repair ? Michael Paul 4 1,407 09-30-2012, 11:26 AM
Last Post: db (martinez, ca.)
  Omnibook 300 battery cells Dave Britten 5 1,712 08-15-2012, 11:54 AM
Last Post: Massimo Gnerucci (Italy)
  A cheap HP41C for sale...........999 EURO only aurelio 4 1,524 06-04-2012, 03:46 PM
Last Post: jerome ibanes
  HP41C: Factorial (kind of) in MCODE Frido Bohn 7 2,001 05-26-2012, 09:18 AM
Last Post: Frido Bohn
  OT-N cells hide & seek Matt Agajanian 15 3,318 05-26-2012, 07:53 AM
Last Post: Raymond Del Tondo
  Picture of HP41C from "The Dream is Alive" Christopher Johnson 0 757 04-20-2012, 02:38 PM
Last Post: Christopher Johnson
  HP41C "Power Module" Frido Bohn 10 2,305 01-03-2012, 03:35 PM
Last Post: Geir Isene
  HP Time Module+Overlay! 82182A for HP41c robertoataulfo 1 814 01-01-2012, 12:33 PM
Last Post: Howard Owen

Forum Jump: