On Wed, 22 Jun 2011 03:41:12 -0700 (PDT), "
wrote:
On Jun 21, 8:43Â*pm, wrote:
On Tue, 21 Jun 2011 05:34:50 -0700 (PDT), "
wrote:
On Jun 20, 7:44Â*pm, wrote:
On Mon, 20 Jun 2011 14:07:19 -0700 (PDT), "
Best practice is not always possible - which is why I say better
charged than flat and open circuit - and better flat and open circuit
than flat and shorted for a battery - better flat and shorted for a
single cell.
You don't have to agree with me, but that's what I've always been
taught - and from Â*what I gather from the very limited information on
the net, nothing has changed my mind.
Long term CELL storage - drained and shorted
Long term BATTERY storage - DO NOT SHORT.
If you cannot store drained and shorted (which is not practical for a
BATTERY of cells,) store charged - and recharge every few months.
As usual, you are free to store YOURS however you want.
And it's a free world - you can agree with me, or you can dissagree
with me.
So far nothing YOU can cite proves me wrong.
At least I've cited multiple credible sources that disagree with
Panasonic. Â*You've cited exactly one source, Panasonic and
choose to rely on that to establish what you call best practice.
And even that one source does not say that not keeping
them charged in storage will lead to damage, shorter life,
etc. Â*It's quite possible it only leads to what some of the
other sources say, which is that if left discharged it will
take several charge/discharge cycles to get them back
to full capacity. Â*That could be behind the Panasonic
recommendation, but we don't know because Panasonic
does not explain what the issue is.
Relying on one source and then claiming that establishes
best practices is a big leap.
Â*What part of "You don't have to agree with me, but that's what I've
always been taught - and from Â*what I gather from the very limited
information on the net, nothing has changed my mind." do you not
understand?
The part where you then proceed to claim that the " best practice"
is not to store them discharged. Fact is, if anything, there are
more sources saying to in fact store them discharged. It's
Panasonic that says that you should keep them charged.
There is not enough definitive information on the net to establish
what is correct - or if there is, in fact, any REAL difference.
The part where you then proceed to claim that the " best practice"
is not to store them discharged.
Over the years I've been taught you keep them charged, but not on
float, if you cannot store them DEAD and shorted - and Â*you NEVER
short a string of cells in series.
Shorted dead strings are OUT due to the danger of cell reversal.
Again, YOU are the only one here who ever suggested shorting
batteries. None of the sources I've seen, nor the many I've
cited say that.
That leaves dead open circuit, or charged.. The question that remains
is which is most likely to grow cadmium needles?? It APPEARS dead open
circuit batteries are more likely to suffer this than charged
batteries, but nothing totally definitive has been produced to say for
sure.- Hide quoted text -
- Show quoted text -
Appears based on exactly what? Certainly nothing that you've cited,
just your own speculation. The one source you provided, Panasonic,
doesn't say it.
Well, you can look at wikipedia , if you put any stock in that
source, for information about cell reversal, and mention of shorting
cells for storage - but I don't use Wikipedia as a sourse.
http://www.saftbatteries.com/SAFT/Up...ft/PDF/tn1.pdf
is talking about flooded NiCad batteries and recommends storing them
filled and discharged, and notes that shorting is not required.
NOTE - This is a FLOODED battery for aircraft use.
Nasa is the only source that I have found on the net so far that is
not manufacturer specific OR just some useless rambling by idiots like
yourself and Me.
They are quoted he
http://users.frii.com/dlc/battery.htm
and I'll quote from there so you don't need to follow the link and
then find the relevant part.
SOME of this is not from the NASA site - so best you look up the link
given - and research the rest yourself (from Nasa - it should be on
the net somewhere in "virgin" form).
What you are looking for is:
NASA Reference Publication 1326, February 1994 Handbook for Handling
and Storage of Nickel-Cadmium Batteries: Lessons Learned by Floyd E.
Ford Swales & Associates, Beltsville, Maryland) and Gopalakrishna M.
Rao, Thomas Y. Yi (Goddard Space Flight Center, Greenbelt, Maryland)
Published by NASA Scientific and Technical Information Branch.
"Storage of NiCd Batteries
Guideline No. 2 Flight batteries should be maintained in a discharged
and shorted condition and stored at cold temperatures when not
required for "critical" spacecraft testing. Optimal temperature is
around 0 degrees C. NASA does it this way:
Discharge at C/2 constant current rate to first cell at 1.0 Volts
Drain each cell with a 1 ohm resistor to less than 0.03V
Short each cell with a bar
Place batteries in a sealed bag with dessicant (stops condensation)
Store in cold temperature (about 0 deg C) "
Also:
"Guideline No. 8
Batteries should not stand on open circuit for more than 7 days
without being charged. Charging should be initiated only after
implementing Guideline No. 3. "
Also:
"Guideline No. 9
A battery should be "reconditioned" if it has been on open circuit,
subjected to intermittent use, i.e, open circuit, trickle charge,
occasional discharge, etc., for a period of 30 days. Reconditioning is
effected by performing the following sequence at 20 deg C:
discharge at C/2 constant current rate to first cell at 1.0V
Drain each cell with 1 ohm resistor to less than 0.03V
Short each cell for a minimum of 4 hours
Recharge battery at C/20 constant current rate for 40 hours +/- 4
hours (see NOTE below)
NOTE: The re-charge method following step 2 is not critical if the
cells have not been discharged and shorted for extended periods. After
a few hours (4-8) at the C/20 rate, charging at high rates is
acceptable. If the battery is integrated into the spacecraft, final
charging can be accomplished with the spacecraft battery charger. "
Also:
"The final one is our most common fault, don't let your packs just lie
around. When not in use they should be either stored shorted, or, if
you are about to race with one, on a C/60 or C/100 trickle charge in
preparation for use. When I say shorted I mean that each cell is
shorted, not the whole pack. You can't short your whole pack at once
without risking damage to it! Also note the careful process used to
short cells."
Note, Batteries stored discherged - one cell at a time - and shorted.
We do not know if these are flooded cells or "dry" type cells.