2/3 AAA NiMH batteries

[Brian]

Anyone tried 2/3 AAA NiMH batteries in a HP41C ?

Here's a website that sells them.

http://members.aol.com/davthacker/radicalrcbatteries.htm
see Sanyo Single Cells section

-Brian
HP41CX RULEZ!

[Steve (Australia)]

Size N is better :-)

They're very commonly (and cheaply) found as replacement batteries for protable (as in not mobile) phones.

Major problem is that they usualy come in sets of three, but they're so cheap you can buy 2 sets.

[Brian]

Are you saying N size NiMH batteries are available?

I only have the 4 'N' battery holder for my HP-41CX.
2/3AAA size batteries will fit in it too. I have
been using NiCad N cells but would rather get NiMH.

-Brian

[David Smith]

Assuming that you want to use them in the rechargeable battery pack, yes they can be made to fit with some shim spacers. You might not want to do it though. These cells are only 50maH, the regular 1/2N cells are 80maH. The charger dumps 15ma of charge current into the cells and you risk over charging them after only 4 hours. A better solution may be 150maH NiMH cells. They will need a 3/16 inch or so thick shim along the back of the cell string since they are around .160 inches shorter than the 1/2N cells.

[Steve (Australia)]

I think Brian was thinking about using them in the standard battery holder as opposed to replacing cells in the nicad pack.

I have sucessfully replaced the 1/2 N cells with 1/3AA cells. This requires quite a bit of work milling and cutting plastic, but you get about 2x the capacity. For the real extreme hardware hackers out there, if NiMH come in this size you could do even better :-)

[Katie Wasserman]

Either the 1/3-AAA or 1/2-N nicads will work in the 82120A battery pack. The 1/3-AAA's are more readily available but they are harder to make fit. The 1/2N are still available and are an exact replacement. See the article (on this site) that I wrote for more details.

[Steve (Australia)]

Yes, but 1/3 AA have certain advantages :-)

Although not for the user who wants cosmetic perfection.