Where to find odd sized batteries?

[Minjin]

I'd like to find a rechargeable lithium replacement for 3xLR44 batteries. The reason is because my HP calculator seems to chew them up and I'm tired of replacing them every 6 months. I still need to test exactly what voltage range it can handle but I figured I'd look for battery options in the meantime.

http://en.wikipedia.org/wiki/LR44_battery

So, it needs to be about 11mm in diameter and 15mm in length. Any ideas?

 

[Flash_Gordon]

I do not know of any rechargeable solution that will be 4.5V and fit that form factor. If you use your calculator a lot, then replacing the cells twice a year is not too bad.

You should be using SR44 cells as opposed to LR44. They cost more but should give longer life in a calculator.

Also, consider the source of your cells. Many of the "cheap" LR44 are of poor quality and questionable heritage. They may be weak from the start.

Mark

 

[Fallingwater]

I tend to replace button cells with external carbon-zinc AAs (I have a lot sitting around from shopping on DX) in a holder glued to the device in question. If extreme portability and shape isn't an issue, I'd advise you to do the same.

 

[Minjin]

Thanks for the opinions guys.

Can anyone answer the question? I see people with small, sub AAA sized lithium batteries in custom lights. Where can I find a selection of these?

 

[altis]

GP make a selection of NiMhs in curious sizes.

http://www.gpbatteries.com/html/techinfo/nimh.asp

 

[Fallingwater]

AW sells tiny LiIon cells. I think the smallest he has is the 10180, which is used by the Orb Wee. I'm not sure if it's small enough to be swapped in place of three LR44 cells, though.

You *might* be able to get them from BatterySpace too.

 

[emitter]

btw which HP are you talking about?
the 12c is supposed to have very low power consumption but mine seems to eat cells.
I measure 11.4 x 5.33(x)=16 mm. My measurements are slightly below what's listed on the wikipedia battery size chart.
I'd suggest lithium, but 3v might make the calculator think it's low.

Sounds like you're stuck with SR44's, silver oxide have more capacity and slightly higher nominal voltage than the LR44 alkalines.