Re: NiCd Battery Storage

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "robert heidlebaugh by way of Terry Fritz <twftesla-at-qwest-dot-net>" <rheidlebaugh-at-desertgate-dot-com>

Mu experience if stored with no charge for a year or so they wont take a
charge so I zap them with a quick shot of 12V car battry and they usualy
will then start to charge, but not allways. I DID NOT SAY 12V STEADY that
will explode them in your hand. Use them or loose them is good advise.
  Robert  H

> From: "Tesla list" <tesla-at-pupman-dot-com>
> Date: Wed, 21 Aug 2002 23:26:36 -0600
> To: tesla-at-pupman-dot-com
> Subject: Re: NiCd Battery Storage
> Resent-From: tesla-at-pupman-dot-com
> Resent-Date: Wed, 21 Aug 2002 23:28:16 -0600
> 
> Original poster: "Brian by way of Terry Fritz <twftesla-at-qwest-dot-net>"
> <ka1bbg-at-webryders-dot-net>
> 
> Hi, I worked with Arthur Huse who assigned a patent to Bosch for Ni-cad
> batteries. His advice"use them or loose them" the reason is inexpensive
> Ni-cad batteries, the separator and chemicals and plated metal parts corrode
> and the seals loose the moisture. Some very expensive Ni-cads have been in
> use for 30 years and still working fine. The result of hermetically sealed
> container with expensive solid metal pieces inside.
> My buddy a Master Electrician says run them down till they stop and then
> charge. They use the same pak's of batteries day in and out and get 3 to 4
> years out of a set! Instructions on my Hitachi drill says run em flat. cul
> brian f.
> ----- Original Message -----
> From: "Tesla list" <tesla-at-pupman-dot-com>
> To: <tesla-at-pupman-dot-com>
> Sent: Wednesday, August 21, 2002 7:35 PM
> Subject: Re: NiCd Battery Storage
> 
> 
>> Original poster: "davep by way of Terry Fritz <twftesla-at-qwest-dot-net>"
> <davep-at-quik-dot-com>
>> 
>>> I read
>> 
>> Where?
>> There is much 'hooey' writ about batteries.
>> 
>>> that NiCd batterys should be stored uncharged.
>> 
>> Last manufacturer's data i saw (NOT real
>> up to date) was that either was OK, with a
>> MILD preference for discharged.
>> 
>>> Is this still true for older nicads that have been charged
>> 
>>> and discharged a number of times?
>> 
>> I've seen no data.  A charged battery, over time,
>> will become a discharged battery, by itself.
>> 
>>> What about storing a newer battery that has seen only one or two
>>> charge/discharge cycles?
>> 
>> Same answer.
>> 
>> 
>>> What would be a good proceedure for discharging a battery pack?
>> 
>> cf below, per manufacturers recommendation (last I
>> had).
>> 
>>> discharge until the output voltage drops off then stop,
>> 
>> This one.  Specifically, look for a 1.2 V 'step'
>> drop in battery (cf below) output.  (1 V drop
>> is ok) then STOP.  eg a nominal 6 cell/7.2 v
>> battery should not be discharged below (7.2-1.2)
>> or 6V.  Reasoning:  one cell will drop out first,
>> go thru zero V, then _reverse_ as the remainder
>> force current backwards.  This is BAD for the
>> reversed cell.  If discharging lots of current:
>> VERY bad.
>> (Yes: Manufacturers more or less match the cells.
>> One will still drop out first...)
>> 
>>> or continue discharging until current flow is minimal?
>> I wouldn't.  cf above.  I'd expect damage.
>> 
>> 
>>> BTW, I use 9 volt nicads for portable operation of a SSTC
>> 
>>> pulse generator, and to run a MOSFET driver circuit.
>> How many cells?
>> 
>> 7? 8?
>> 
>> 1) I'd be tempted to store them charged but NOT
>> try to 'float' them.  Let them discharge by
>> themselves.
>> 1a) Lead-acids tend to be stored on a 'float' charge.
>> This tends to overcharge and dry out nicads, leading
>> to early death, leakage, etc, unless done VERY
>> exactly...  Simplest is to 'leave 'em', next
>> simplest _controlled_ (V- 1.2V) discharge.)
>> 
>> 2) Minor point of usage:
>> Cell: a single unit.
>> Battery: A buncha cells.
>> If dealing with individual _cells_, can discharge to
>> zero.  If dealing with _battery_, BAD thing to
>> discharge to zero, as this means some cells are
>> having current forced thru backwards....
>> 
>> best
>> dwp
>> 
>> ...the net of a million lies...
>> Vernor Vinge
>> There are Many Web Sites which Say Many Things.
>> -me
>> 
>> 
>> 
>> 
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