HP-11C - 25 years on original batteries!


I received my HP-11C calculator as a gift in 1981 while studying physics at Central Washington University. I used it intensely for my four years at the university, and have used it as my main calculator ever since I graduated. I have never changed the batteries in the last 25 years! Every day I turn it on and wonder if it will be its last day – but it just fires-up and is ready for work. I’m not sure if there are any records for battery longevity, but 25 years seems like an awfully long time. I’m not sure if it’s a testament to the 11C or to the batteries; my guess is both can share the credit. If anyone has a similar story for 25+ years on the same batteries, let me know.

Edited: 15 Jan 2006, 4:05 p.m.


You should regularly change the batteries even though they are still good. One day you will wake up and find the battery seals cut loose and spewed battery barf all over the innards of you wonderful pet machine.


I changed the batteries on my HP-11C in october. They did last 20 years.
They were not actually dead, but the "snowflake" sign has been on since the last year or so.

The change was a "birthday present": according to the serial number, my 11C was built in the last week of october in 1985.

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