Alkaline Battery Switched its polarity

Vikas Sontakke · Jan 29, 2008

I had relatively new set of 4 x AAA CVS alkaline in TI-89 calculator. My son complained that the calculator shut off on him suddenly after warning the battery symbol. The batteries have been in the calculator for no more than a month.

The three batteries showed 1.35V but one of the battery is now showing negative 0.96V I was actually able to put the battery upside down in KD buckle and it actually lit up for a fraction of second.

Has anybody seen a situation like this ?

- Vikas

Brlux · Jan 29, 2008

It sounds like the one cell was nearly completely dead to start with and it in effect was charged backwards by the other 3 cells. Alks can be recharged slightly but it is not a good or safe idea, It was like putting the one dead cell in a charger backwards. It seems to have accepted a vary small reverse polarity charge.

Darkpower · Jan 29, 2008

Vikas Sontakke said:
I had relatively new set of 4 x AAA CVS alkaline in TI-89 calculator. My son complained that the calculator shut off on him suddenly after warning the battery symbol. The batteries have been in the calculator for no more than a month.

The three batteries showed 1.35V but one of the battery is now showing negative 0.96V I was actually able to put the battery upside down in KD buckle and it actually lit up for a fraction of second.

Has anybody seen a situation like this ?

- Vikas

Yes negative cell reversal happens quite frequently even in NiMh and other chemistries. You must always use fresh alkalines or cells with similar state of charge, similar brands, common batches, etc. The theory is that one of the cells may discharge to zero before the others do, then the other cells in the series will drive a negative voltage into the dead cell. Stuff like that will lead to leakage in alkalines and major problems in lithiums-ions.

Vikas Sontakke · Jan 29, 2008

They were all new cells from the same package when installed.

- Vikas

Thujone · Jan 29, 2008

Doesn't mean that there wasn't a bad egg in the pack..

sawlight · Jan 29, 2008

I needed some batteries for the camera a week ago. Stopped at a gas station on the way to get them. They were Durracells, but in an unbranded package. Out of dates I am assuming. The forst package I was given one of the batteries already had leaked and was covered on the bottom with white fluff!!! I asked for another package. That one seemed to work. But yeah, it's not an uncommon thing to get a bad batch anymore!!!

Walleye1 · Jan 29, 2008

Is a "durracell" the same kind of thing as "krab" legs?

hopkins · Jan 30, 2008

Hi Vikas
Seems that calculator really drains batteries fast. Maybe sell it
and buy a solar powered one. No batteries needed! Save money
on batteries and the horror of dead batteries at school during a test!

Hopkins

jrmcferren · Jan 31, 2008

hopkins said:
Hi Vikas
Seems that calculator really drains batteries fast. Maybe sell it
and buy a solar powered one. No batteries needed! Save money
on batteries and the horror of dead batteries at school during a test!

Hopkins

The Ti89 is a graphing calculator, I don't know of any solar powered calculators at this time.

jrmcferren · Jan 31, 2008

Double post

TorchBoy · Feb 1, 2008

I can only remember one cell I've seen that had a negative voltage, an alkaline button cell. And FWIW just recently I saw my first button cell that had popped open - I presume because it was reverse charged.

Marduke · Feb 1, 2008

jrmcferren said:
The Ti89 is a graphing calculator, I don't know of any solar powered calculators at this time.

I always keep a spare set of AAA's around for my TI-89, and I always took a spare solar powered TI-30x IIs or TI-34x on test days.

Mr Happy · Feb 1, 2008

Those big programmable graphing calculators like the TI-89 are power hungry beasts. 4xAAA alkalines provide far more power than a small solar cell can produce.

65535 · Feb 1, 2008

I have 4 duracell AAA's in my Ti-84 plus silver edition calc. and they last around 1 year without death, used daily.

Alkaline Battery Switched its polarity

Vikas Sontakke

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