Could I use AA alkaline batteries in a HP 35?

[Miguel Toro]

I think of using NiMHs but I just wanted to know if it is safe for the calculator.

Thanks,

Miguel

[Stefan Vorkoetter]

Where would you put them?

[Miguel Toro]

The original Battery Pack was dead so I opened it (cuting by the seam, as the curator says) and arranged it so now I am able to put in and take out NiMh batteries easily. So now I want to try some alkalines if that is safe. Maybe I can show a picture of what I did (it is ugly but it works).

[Stefan Vorkoetter]

Oh, sorry. I thought you meant HP 35s. I wouldn't use alkalines in an HP-35 because their voltage is higher. Good NiMH batteries (like Sanyo Eneloops) will far outlast the original NiCds.

[Miguel Toro]

Ok. Thank you. So 4.5v can indeed damage the calculator.

Regards,

Miguel

[Jeff O.]

If I recall correctly*, a fully charged nicad puts out about 1.5 Volts. If you check the schematic of the classic charger, it indicates that the logic supply voltage is 4.2 Volts. Based on this information, it is hard to believe that 4.5 Volts would present any danger. However, better safe than sorry, so unless you have a strong need to use alkalines, why take the risk. It would also be bad if you happened to plug the charger into your calculator with alkalines installed.



^{*-which I apparently do not, see below}

Edited: 15 Sept 2007, 9:04 p.m. after one or more responses were posted

[Stefan Vorkoetter]

A fully charged NiCd puts out about 1.3V which quickly drops to 1.2V and then stays there for a long time. At 1.1V, it's almost dead.

Stefan

[JoeFrisco]

NiCads are 1.2 V. . . But I will accept the 1.3 V potential as offered by Stefan
NiH are 1.2 V . . So you should be able to drop NiH cells for NiCad cells

Alkaline Cells are 1.5 V.

Edited: 17 Sept 2007, 7:47 p.m.

[Mad Dog ebaycalcnut]

No.

[Miguel Toro]

Clear as water (as we say in Spanish)!. Thank you all for yours answers.

Miguel

[Chuck Sommer]

I agree that using alkaline batteries is not a good idea. The first problem is that a really new alkaline battery can put out 1.6 volts or higher, but I suspect the calculator would be OK with that (4.8 volts). The more important problems are (as stated earlier) what if you put your charger to the calculator with the alkaline batteries, and if the alkaline batteries are left in the calculator long enough they will LEAK. For the last reason I would not try alkaline batteries as I can imagine putting them in and forgetting about it for a few years... and then being very unhappy.

Chuck