Natural Science Forum / Chemistry / Electrochemistry / January 2005

How much longer would the battery of a digital wristwatch last if one
had to press a button to view the time? (Otherwise display is blank.)

With a Sanyo HR-AUC cell, how much capacity degradation should I expect when
they are discharged, with a cell temperature of roughly 0C?  Assume charge
is done at 20C or thereabouts.
My load is pretty "spiky", with low current of 100-ish mA, but high current

It seems as of late that I am constantly tilting
at windmills on this one. I keep running into people
saying that you should "condition" Li-Ion batteries --
before normal use you should completely discharge

I'm trying to select the best li-ion batteries for use in a light EV
application.  The battery needs to be able to withstand a 1C discharge
rate for extended durations under a wide range of enviromental
conditions, ie at ambient temperatures from -20 C to 45 C, very high

Sorry if these are newbie questions:
I have a charger with a label that says "Charge only nickel-cadmium type
rechargeabel batteries. Other types may burst." In spite of this warning
note, I'd like to charge my Ni-MH batteries with it. Is there any real

Does NiMH-batteries have "memory". I did't think so.
But yesterday a hifi-freak told me they have some memory.
Can someone say something wise?

does specific-gravity of a conventional lead-acid cell, linearly
measure its AmpHour capacity?
If not, what exactly does it indicate with respect to the battery
user's needs?

Anti-seize goop works on the principle of sacrificial anodes, but the
anode is powdered.  ok.
So does that imply that, just like the zinc on a boat, the goop
eventually is no longer electrochemically protecting the joint?

Hello,
For a bibliography about impedance measurements on PEM Fuel Cells, I am
looking for well explained documents about the Current Interruption Method
available on the net.

To increase the run time of a UPS system (APC Smart UPS-1000XL), I purhcased a
couple of Marine/Deep Cycle batteries (Exide Nautilus Gold NG-27, 105AH rating).
The battery system is nominal 24V. APC sells battery packs with 4 12V/18AH gelled
cells, but these cost a lot and do not ...

Over the past week the has been so excellent feedback(threads) on my
question of water conductivity.
In a few thread the value of 18.3MR (0.055uS) was mentioned, forgive me for
being pedantic but could somebody help by quoting a reference that cites

I have tried google,CRC Handbook of Chemistry and Physics, Perry's Handbook
without result.
If you can find magnetic susceptibility of sodium hydrosulfide (NaHS) -
please write the value (volume, mole or gram based susceptibility and the

My electric water heater is leaking.  Is this likely due to a cracked
glass inner liner, or a corrosive action?  I know I'll need a new one,
but how long might it last just leaking rather than a full burst?  The
outside metal liner has come open.

i have just finnished charging 2 6v 90amph batteries given to me from an old
electric pallet lift truck
they have been standing for some time so where sulfated
anyway been charging them for a few weeks and seemed ok with reduced

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(Keeping in mind that I am an electronics engineer with quite
limited knowledge of chemistry and some experience in designing