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- From: akcs.jwtrav@hpcvbbs.cv.hp.com (John Wettroth)
- Date: Thu, 23 Jul 1992 08:40:02 GMT
- Subject: Re: batteries
- Message-ID: <2a6e63b8.1463.3comp.sys.hp48.1@hpcvbbs.cv.hp.com>
- Path: sparky!uunet!zaphod.mps.ohio-state.edu!usc!sdd.hp.com!hp-cv!hp-pcd!hpcvra!rnews!hpcvbbs!akcs.jwtrav
- Newsgroups: comp.sys.hp48
- References: <35980@sdcc12.ucsd.edu> <1992Jul23.095540.9554@waikato.ac.nz>
- Keywords: batteries
- Lines: 18
-
- Nickel Cadmium batteries put out 1.25 volts when very fresh and quickly
- get down to 1.1 volts. Alkalines put out 1.55 volts when fresh and reach
- a working voltage of 1.4 volts for most of their life. At end of life
- they go to about 1 volt (<10% capacity). HP-48's sense battery voltage
- for the low battery icon. This is at about 3.1 volts or about 1.03 volts
- per cell. Nicads also have about 1/4 the capacity (density) of Alkalines
- so the their life would be 1/4 as long right off the bat (excuse the pun)
- but considering the low battery detector icon would probably be about
- half this much. If you're using your calculator often and for long
- sessions, you would probably get about 1/8 the life out of NiCd's and I
- would imagine your low battery Icon would be on about half the time.
- Some other notes of caution if I haven't talked you out of it yet. The
- self discharge rate of NiCd's is very high- a few months at room temp.
- If you left your calculator sitting around for a month or two with NiCd's
- in it, it would develop amnesia. Overall, not a good idea. As the
- previous note said, buy one less donut per week and put the money in your
- shoe. By the time your alkaline batteries die, go into the drug store
- and pour out your shoe on the counter- Good Luck.
-
-