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Full Version: OK to use 2 CR123 cells in an HP41C ?
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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.


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.

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.

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.