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chasb(at)satx.rr.com
Guest

Posted: Tue Mar 06, 2012 12:38 am Post subject: Re-juvinate a NiCad Battery?

Is there anyway to rejuvenate an old NiCad battery? I have an iCOM  

hand held radio with a rechargeable battery pack. I assume the battery  

is a NiCad. The radio requires a 9.6v charge, but I can't get the pack  

charged above 9.25v. At that level I can listen to the radio, but  

cannot transmit. The charger that came with the radio puts out 10.4v  

when hooked to the battery, but the battery voltage won't increase  

even after a day or so of recharging. Is there any way to save this  

battery pack?



Charlie Brame

RV-6A  N11CB

San Antonio

nuckolls.bob(at)aeroelect
Guest

Posted: Tue Mar 06, 2012 6:36 am Post subject: Re-juvinate a NiCad Battery?

At 02:37 AM 3/6/2012, you wrote:

  	  Quote: 	
		  --> AeroElectric-List message posted by: Charles Brame <chasb(at)satx.rr.com>



 Is there anyway to rejuvenate an old NiCad battery? I have an iCOM  

 hand held radio with a rechargeable battery pack. I assume the battery  

 is a NiCad. The radio requires a 9.6v charge, but I can't get the pack  

 charged above 9.25v. At that level I can listen to the radio, but  

 cannot transmit. The charger that came with the radio puts out 10.4v  

 when hooked to the battery, but the battery voltage won't increase  

 even after a day or so of recharging. Is there any way to save this  

 battery pack?



 Charlie Brame

 RV-6A  N11CB

 San Antonio 	


         Yes . . . maybe . . . and perhaps no. NiCads can suffer

         certain degrading of chemistry that prevents any recovery.

         Some 'failed' batteries have grown whisker-shorts in

         the cells that MIGHT yield to a low voltage impulse

         of many amps. For example, if you have access to a single

         2 volt lead-acid cell or even another FAT ni-cad cell,

         connecting it in parallel with the suspect whisker-short

         might fuse it and recover the cell's utility.



         The best advise I can offer is to re-cell your battery

         pack. There are battery re-build companies that do this

         quite well. Your battery pack is probably an array of

         AA sized cells which you can purchase with solder tabs

         from places like:



  http://tinyurl.com/74c2x27 



  http://tinyurl.com/899bjcu 



 



 

   Bob . . .    [quote][b]

ronburnett(at)charter.net
Guest

Posted: Tue Mar 06, 2012 6:53 am Post subject: Re-juvinate a NiCad Battery?

You might take the battery to Wholesale Batts. to see what they have for 

a replacement. I did that for a radio battery for my Luscombe that has 

no elect. system.  I had to modify the length of the case that held the 

batt. but for less than $20 I have a much better system that I can 

recharge.  The old one quit recharging.



Good luck,



Ron Burnett





On Tue, Mar 6, 2012 at 2:37 AM, Charles Brame wrote:



 	  Quote: 	
		   

 <chasb(at)satx.rr.com>



 Is there anyway to rejuvenate an old NiCad battery? I have an iCOM 

 hand held radio with a rechargeable battery pack. I assume the battery 

 is a NiCad. The radio requires a 9.6v charge, but I can't get the pack 

 charged above 9.25v. At that level I can listen to the radio, but 

 cannot transmit. The charger that came with the radio puts out 10.4v 

 when hooked to the battery, but the battery voltage won't increase 

 even after a day or so of recharging. Is there any way to save this 

 battery pack?



 Charlie Brame

 RV-6A  N11CB

 San Antonio

Mike Welch

Joined: 13 Feb 2011
Posts: 272

Posted: Tue Mar 06, 2012 7:31 am Post subject: Re-juvinate a NiCad Battery?

Charlie,

  I also have an Icom handheld radio.  Years ago, when my Icom A22 ni-cad OEM battery pack died, I bought their

(expensive) AA battery holder (now they're half price).  It comes empty, and you simply use 10 of your rechargeable generic

AA batteries.  In fact, you can use AA ni-cads, or AA NiMHs, or plain old Duracells.  It's just an empty compartment,

and you fill it up with 10 rechargeable AA batteries.

  For years I've just used the 1.2 volt NiMH's I got off of eBay.  A couple of years ago, I bought the new rechargeable

1.5 volts models, although it worked just fine on the (10) 1.2 volt versions.

  Here is the container for the A22.  I would imagine you could get one of these for all their handheld models, although I haven't looked.

(you didn't mention what model you have)

http://www.ebay.com/itm/CM-167-10-AA-Cell-Battery-Case-ICOM-Air-Band-IC-A3-IC-A3E-IC-A22-IC-A22E-/160650004281

?pt=LH_DefaultDomain_0&hash=item25677c8739#ht_3307wt_1063

Mike Welch

 	  Quote: 	
		   At 02:37 AM 3/6/2012, you wrote:

> 

> 

> Is there anyway to rejuvenate an old NiCad battery? I have an iCOM  

> hand held radio with a rechargeable battery pack. I assume the battery  

> is a NiCad. The radio requires a 9.6v charge, but I can't get the pack  

> charged above 9.25v. At that level I can listen to the radio, but  

> cannot transmit. The charger that came with the radio puts out 10.4v  

> when hooked to the battery, but the battery voltage won't increase  

> even after a day or so of recharging. Is there any way to save this  

> battery pack?

> 

> Charlie Brame

> RV-6A  N11CB

> San Antonio

skywagon

Joined: 11 Feb 2006
Posts: 184

Posted: Tue Mar 06, 2012 10:59 am Post subject: Re-juvinate a NiCad Battery?

Mike,

Great tip for the Icom A-22..Thanks.

David

PS:  I do not know any way to rejuvenate an aged, encapsulated NiCad 

'battery' pack.  If one has surgical skills and can cut the pack apart, then 

you can find and toss the offending cell(s).  By that time, it would make 

more sense to toss them all and start with all fresh.  Still a big job for 

encapsulated type batteries....



___________________________________________________________________

---

ceengland(at)bellsouth.ne
Guest

Posted: Tue Mar 06, 2012 11:20 am Post subject: Re-juvinate a NiCad Battery?

I've done the 'repopulate' trick in an OEM pack (different brand radio) 

by replacing the nicads with NiMH to get roughly the same voltage & more 

AH's. Still had to stuff the pack with packing material to take up the 

empty space in the pack. Still working fine after many months; I use the 

same AC charger that came with the radio.



Charlie



On 03/06/2012 12:57 PM, David Lloyd wrote:

[quote] 

 <skywagon(at)charter.net>



 Mike,

 Great tip for the Icom A-22..Thanks.

 David

 PS:  I do not know any way to rejuvenate an aged, encapsulated NiCad 

 'battery' pack.  If one has surgical skills and can cut the pack 

 apart, then you can find and toss the offending cell(s).  By that 

 time, it would make more sense to toss them all and start with all 

 fresh.  Still a big job for encapsulated type batteries....



 ___________________________________________________________________

 ---

rparigoris

Joined: 24 Nov 2009
Posts: 805

Posted: Tue Mar 06, 2012 11:56 am Post subject: Re-juvinate a NiCad Battery?

Just a quick note on AA and AAA rechargeable cells. The latest and greatest LSD NiMh cells are well, great! LSD is Low Self Discharge, so cells that have LSD membranes can go a long period of time without discharging. Home Depot sells Energizer cells in AA and AAA that are LSD cells. I also find in the cold they work well. I haven't tried to solder them yet, but I suspect it will not be a problem. Normally soldering I scuff with a little 100 or so sandpaper, clean with Isopropyl alcohol, put a mini drop of mild activated flux, using a 150 watt iron quickly touch, get solder to flow (this happens very quickly) and cool with a damp paper towel "right now!). To interconnect cells I use solder braid not allowing it to wick and make the braid solid. Works great. You can use a lower wattage iron, but don't mess around, flow and cool. I don't think I ever lost a battery due to damaging because of soldering. 

 	Once you solder them into a pack, just use a conmstant 1/10C style charger or a peak charger if you have one. An LM1117 or LM317 with one resistor as bob suggested a while back works fine. Charge C/10 for 14 to 16 hours. 

 	The worst batteries I ever had to solder were long ago LiIon can cells. For those I tinned with Utectic acid core solder. It was some sort of stainless that I just couldn't get to tin with all the solders and fluxes I could find. The Utectic is pretty amazing stuff. Once tinned I solder sucked off as much as I could, then tinned and sucked a few times with 63-37, then soldered the braid on. I did that pack in the early2000s, and there is no sign of corrosion or eroding on that pack as of today. 

 	Ron P.    [quote][b]

email(at)jaredyates.com
Guest

Posted: Tue Mar 06, 2012 1:37 pm Post subject: Re-juvinate a NiCad Battery?

I'm also very impressed with the LSD cells. I soldered a pack just like usual and they behaved just as the nicd cells always have. It's nice to be able to pick up the rc airplane transmitter and not have to worry about whether it has been on the charger lately. I would recommend these cells especially for applications that involve such infrequent use. 

On Mar 6, 2012, at 14:54, rparigor(at)suffolk.lib.ny.us (rparigor(at)suffolk.lib.ny.us) wrote:



[quote]

 	Just a quick note on AA and AAA rechargeable cells. The latest and greatest LSD NiMh cells are well, great! LSD is Low Self Discharge, so cells that have LSD membranes can go a long period of time without discharging. Home Depot sells Energizer cells in AA and AAA that are LSD cells. I also find in the cold they work well. I haven't tried to solder them yet, but I suspect it will not be a problem. Normally soldering I scuff with a little 100 or so sandpaper, clean with Isopropyl alcohol, put a mini drop of mild activated flux, using a 150 watt iron quickly touch, get solder to flow (this happens very quickly) and cool with a damp paper towel "right now!). To interconnect cells I use solder braid not allowing it to wick and make the braid solid. Works great. You can use a lower wattage iron, but don't mess around, flow and cool. I don't think I ever lost a battery due to damaging because of soldering. 

 	Once you solder them into a pack, just use a conmstant 1/10C style charger or a peak charger if you have one. An LM1117 or LM317 with one resistor as bob suggested a while back works fine. Charge C/10 for 14 to 16 hours. 

 	The worst batteries I ever had to solder were long ago LiIon can cells. For those I tinned with Utectic acid core solder. It was some sort of stainless that I just couldn't get to tin with all the solders and fluxes I could find. The Utectic is pretty amazing stuff. Once tinned I solder sucked off as much as I could, then tinned and sucked a few times with 63-37, then soldered the braid on. I did that pack in the early2000s, and there is no sign of corrosion or eroding on that pack as of today. 

 	Ron P.     	  Quote: 	
		  

	


[b]

Float Flyr

Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

Posted: Tue Mar 06, 2012 4:50 pm Post subject: Re-juvinate a NiCad Battery?

Having rebuilt several Ni-Cad packs I agree with you entirely.  When one

cell bites the bullet you can be sure the rest are not far behind.  What I

would suggest is to build another pack from newer NIMIH cells which have

longer life and less memory effect. Get the ones with the soldering tabs

already in place.



 All these cells do auto discharge and you will find the total power they

can hold (capacity) deteriorates with age.  You can reduce this

deterioration by only charging your cells to 70% and allowing then to

discharge only to 40%.  From what I've read, a cell fully charged will lose

20% of its capacity in a year.  A cell kept between 40 and 70% charge will

lose only 2% of its capacity.  I think Lithium Ion cells also lose capacity

in similar quantities...  Makes one think about all those little cells in

electric cars eh?



Noel



--

_________________
Noel Loveys
Kitfox III-A
Aerocet 1100 Floats

raymondj(at)frontiernet.n
Guest

Posted: Tue Mar 06, 2012 5:11 pm Post subject: Re-juvinate a NiCad Battery?

Question: How do you determine the percent charge on a battery pack. Is 

it by voltage or current or what.  That's one of my pet peeves with 

rechargeables in everything.  The batteries die from old age rather than 

from reaching the max number of cycles.



Looking forward to hearing about this.

Raymond Julian

Kettle River, MN



"And you know that I could have me a million more friends,

and all I'd have to lose is my point of view." - John Prine



On 03/06/2012 06:48 PM, Noel Loveys wrote:

 	  Quote: 	
		   



 Having rebuilt several Ni-Cad packs I agree with you entirely.  When one

 cell bites the bullet you can be sure the rest are not far behind.  What I

 would suggest is to build another pack from newer NIMIH cells which have

 longer life and less memory effect. Get the ones with the soldering tabs

 already in place.



   All these cells do auto discharge and you will find the total power they

 can hold (capacity) deteriorates with age.  You can reduce this

 deterioration by only charging your cells to 70% and allowing then to

 discharge only to 40%.  From what I've read, a cell fully charged will lose

 20% of its capacity in a year.  A cell kept between 40 and 70% charge will

 lose only 2% of its capacity.  I think Lithium Ion cells also lose capacity

 in similar quantities...  Makes one think about all those little cells in

 electric cars eh?



 Noel

nuckolls.bob(at)aeroelect
Guest

Posted: Tue Mar 06, 2012 8:18 pm Post subject: Re-juvinate a NiCad Battery?

At 07:09 PM 3/6/2012, you wrote:

 	  Quote: 	
		  



Question: How do you determine the percent charge on a battery pack. 

Is it by voltage or current or what.  That's one of my pet peeves 

with rechargeables in everything.  The batteries die from old age 

rather than from reaching the max number of cycles.



Looking forward to hearing about this.


	


    Okay, but you're probably not going to like it.

    Some years ago I wrote an article about the economics

    of using house branded AA cells in my airborne hardware.



http://aeroelectric.com/articles/AA_Bat_Test.pdf



    The thrust of the article went to in-flight reliability

    of my battery powered hand held GPS and Comm radios

    coupled with risk mitigation. One night over west

    TX I found it necessary to change the four AA cells

    out in my GPS receiver. During the fumbles with the

    loose cells in the bottom of the flight bag, I dropped

    one of the last good set of four cells on the deck.



    We'll you can guess how THAT went. Had to turn

    on the (ugh) VOR receivers and finish the trip.

    This event started a train of thought to deduce

    (1) the practicality of carrying a charger on

    trips - another piece of hardware - and using

    rechargeable batteries to be topped off before

    flight . . . or simply putting new cells into the

    device and pitching them when I got home.



    I'd already wrestled with the ni-cads for my

    flashguns and found that under less than ideal

    conditions, I MIGHT be good for a several dozen

    cycles . . . but when the flash gun craps in

    the middle of a shoot and only one cell out of

    the 4 was bad . . . the economics of hassle

    was rearing an ugly head.



    I did try to establish sets of cells that

    had been cap-checked in the last 10 cycles

    or so and tried to keep cells of similar

    capacity together. This also spotted cells

    that were crapping out. I'd pitch them when

    they dropped to 75% of capacity. That preventative

    maintenance process improved on-the-job reliability

    but it also took TIME that was not adding value.

    When cheap cells became available on eBay, I

    started dating the new cells when I put them

    in service and pitched them at 6 months.

    The cost of time to test them exceeded the

    value of the cells!



    Premium, highly advertised batteries in

    one radio (or flashgun) was worth a gallon

    of gas. So I began to wonder just how bad the

    el-cheeso brands of AA alkaline battery could be.



    In the article, you read how even the least

    expensive cells (about 22 cents apiece)

    offered VERY good value for contained energy.



    That's when I began the practice of installing

    a fresh set of cells to go outbound, another

    fresh set to come home. Fresh batteries

    were dropped into the flight bag with a piece

    of masking tape on them. I took the tape off

    when the battery was installed. When I got

    home un-tapped batteries were pressed into

    other service and I never found myself fiddling

    with batteries and battery box covers in flight.



    Wrestling with Ni-Cd or Ni-Mh arrays still

    comes with the attendant uncertainties. Just

    how good are these cells and how closely

    matched are they for capacity? So to this day,

    I still don't use rechargeable cells in flight

    hardware or mission critical devices. The AA

    cells are so cheap that keeping fresh ones in

    the electrowhizzy takes very little time,

    attention and/or expense.



    Now, the short answer to your question: You

    need a device tailored to the task of fully

    discharging a cell and reporting its contained

    energy. I.e. a cap-checker. If you use a lot

    of loose cells, this isn't too hard but if

    the cells in question are in a soldered up

    array inside a radio . . . you're flying

    "blind" with respect to the real reliability

    of the device.



    Cell arrays that are regularly excerised seem

    to do real well. My Makita and DeWalt drill

    batteries seem to be good for a year or more

    but there's a fast charger nearby with another

    battery of unknown quality setting in it.



    Rechargeable batteries are fine on the ground

    but I'm reluctant to fly with them as part

    of my failure tolerance team of electrowhizzies.



http://aeroelectric.com/Pictures/Misc/Vacination_for_Dark_Panel_Syndrom.pdf



   Bob . . .

Float Flyr

Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

Posted: Wed Mar 07, 2012 12:06 pm Post subject: Re-juvinate a NiCad Battery?

The only way I've been able to determine if a battery is reaching its end of

life is to use it.  As a professional photographer I've had lots of

experience with NiCads going dead at the wrong time (Murphy's law) so I used

to always carry a couple of sets of alkalines for backup.  A couple of

things I found when batteries got to the point the just wouldn't hold a

charge I would completely discharge them... keep a short across the

terminals for 24 hr. Then hit them with a current of close to an amp with a

voltage around 3V for about ten seconds... then recharge them normally.  It

seemed to rejuvenate somewhat and remove memory effect.  The only batteries

I tried this on were pretty well discharged at the time of applying the

short.



In recent years I've gone to Lithium cells.  I can't recharge them, the

chance of leakage and fire is too great, but they seem to last forever and a

second backup set is all I'll ever need.  Shelf life of the lithium

batteries is in the order of several years and just about everything I've

tried them in seems to like them whether it's a high current application or

a very low current application.  I have found that lithium batteries that

have used too much power to be used in a photo flash or digital camera will

still last a year or more in remote controls.



Noel



--

_________________
Noel Loveys
Kitfox III-A
Aerocet 1100 Floats

raymondj(at)frontiernet.n
Guest

Posted: Wed Mar 07, 2012 1:21 pm Post subject: Re-juvinate a NiCad Battery?

Greetings Noel,



In an earlier post you mentioned that the life of rechargeable batteries 

could be extended by operating them in a 40% to 70% range.  My question 

is how is the percent of charge state quantified?



Raymond Julian

Kettle River, MN



"And you know that I could have me a million more friends,

and all I'd have to lose is my point of view." - John Prine



On 03/07/2012 02:04 PM, Noel Loveys wrote:

[quote] 



 The only way I've been able to determine if a battery is reaching its end of

 life is to use it.  As a professional photographer I've had lots of

 experience with NiCads going dead at the wrong time (Murphy's law) so I used

 to always carry a couple of sets of alkalines for backup.  A couple of

 things I found when batteries got to the point the just wouldn't hold a

 charge I would completely discharge them... keep a short across the

 terminals for 24 hr. Then hit them with a current of close to an amp with a

 voltage around 3V for about ten seconds... then recharge them normally.  It

 seemed to rejuvenate somewhat and remove memory effect.  The only batteries

 I tried this on were pretty well discharged at the time of applying the

 short.



 In recent years I've gone to Lithium cells.  I can't recharge them, the

 chance of leakage and fire is too great, but they seem to last forever and a

 second backup set is all I'll ever need.  Shelf life of the lithium

 batteries is in the order of several years and just about everything I've

 tried them in seems to like them whether it's a high current application or

 a very low current application.  I have found that lithium batteries that

 have used too much power to be used in a photo flash or digital camera will

 still last a year or more in remote controls.



 Noel



 --

nuckolls.bob(at)aeroelect
Guest

Posted: Thu Mar 08, 2012 7:06 am Post subject: Re-juvinate a NiCad Battery?

At 03:20 PM 3/7/2012, you wrote:




In an earlier post you mentioned that the life of rechargeable 

batteries could be extended by operating them in a 40% to 70% 

range.  My question is how is the percent of charge state quantified?



	It it isn't . . . not without measurements. Many battery

	powered devices, especially laptops have smart batteries

	fitted with circuitry that measures the energy

	required to top off a battery and compares it with the

	energy demands of the computer. As the battery ages,

	the predicted endurance for the battery goes down even

	though the percentage of available capacity gets topped

	off to 100% each cycle.



	The better rule of thumb for both NiCd and HiMh

	technologies is to use them. They seem to enjoy being

	cycled. Unlike the LiIon battery that is damaged by deep

	discharge below 10% or so, you don't hurt the metal

	batteries by taking them all the way to zero. You don't

	want to store them in a discharged state . . . which

	suggests some form of maintainer tray to keep service-

	ready cells topped off for regular use.



	It's almost a certainty that I would have enjoyed much

	longer service lives from metal cells I've owned if

	I had invested time and equipment to their maintenance.

	At some point the economics fall apart when you spend

	many times more $value$ in maximizing the service

	life than the battery costs to simply replace it.



	Bob . . .

raymondj(at)frontiernet.n
Guest

Posted: Thu Mar 08, 2012 7:39 am Post subject: Re-juvinate a NiCad Battery?

Is it voltage that is measured.  Does the manufacturer supply a voltage 

vs. % charge graph or table?  Or is it derived experimentally?



I understand that there are cost/benefit issues here, but my objective 

is to understand the process from a physics perspective for my own 

education.



Thanks again for taking the time to help.



Raymond Julian

Kettle River, MN



"And you know that I could have me a million more friends,

and all I'd have to lose is my point of view." - John Prine



On 03/08/2012 09:04 AM, Robert L. Nuckolls, III wrote:

 	  Quote: 	
		   

 <nuckolls.bob(at)aeroelectric.com>



 At 03:20 PM 3/7/2012, you wrote:

 



 In an earlier post you mentioned that the life of rechargeable batteries

 could be extended by operating them in a 40% to 70% range. My question

 is how is the percent of charge state quantified?



 It it isn't . . . not without measurements. Many battery

 powered devices, especially laptops have smart batteries

 fitted with circuitry that measures the energy

 required to top off a battery and compares it with the

 energy demands of the computer. As the battery ages,

 the predicted endurance for the battery goes down even

 though the percentage of available capacity gets topped

 off to 100% each cycle.



------ SNIP--------
	




 	  Quote:

Float Flyr

Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

Posted: Thu Mar 08, 2012 8:27 am Post subject: Re-juvinate a NiCad Battery?

This post  converted to html

Bob I’ll put my comments in red after each of your paragraphs only because I feel you have so much there AI don’t want to miss anything.

 

--

_________________
Noel Loveys
Kitfox III-A
Aerocet 1100 Floats

chasb(at)satx.rr.com
Guest

Posted: Thu Mar 08, 2012 8:28 am Post subject: Re-juvinate a NiCad Battery?

Bob and others have mentioned trying the 3V/1Amp charge. What device or battery do you use to provide the 3V - 1Amp charge?

Charlie Brame

RV-6A N11CB

San Antonio

----------------------------------------------------------------------------





[quote]Time: 12:06:32 PM PST US

From: "Noel Loveys" <noelloveys(at)yahoo.ca (noelloveys(at)yahoo.ca)>

Subject: RE: Re-juvinate a NiCad Battery?

The only way I've been able to determine if a battery is reaching its end of

life is to use it.  As a professional photographer I've had lots of

experience with NiCads going dead at the wrong time (Murphy's law) so I used

to always carry a couple of sets of alkalines for backup.  A couple of

things I found when batteries got to the point the just wouldn't hold a

charge I would completely discharge them... keep a short across the

terminals for 24 hr. Then hit them with a current of close to an amp with a

voltage around 3V for about ten seconds... then recharge them normally.  It

seemed to rejuvenate somewhat and remove memory effect.  The only batteries

I tried this on were pretty well discharged at the time of applying the-------snip---------[b]

ainut(at)knology.net
Guest

Posted: Thu Mar 08, 2012 8:53 am Post subject: Re-juvinate a NiCad Battery?

Probably not.

David M.

Charles Brame wrote:

 	  Quote: 	
		   

 <chasb(at)satx.rr.com>



 Is there anyway to rejuvenate an old NiCad battery? I have an iCOM 

 hand held radio with a rechargeable battery pack. I assume the battery 

 is a NiCad. The radio requires a 9.6v charge, but I can't get the pack 

 charged above 9.25v. At that level I can listen to the radio, but 

 cannot transmit. The charger that came with the radio puts out 10.4v 

 when hooked to the battery, but the battery voltage won't increase 

 even after a day or so of recharging. Is there any way to save this 

 battery pack?



 Charlie Brame

 RV-6A  N11CB

 San Antonio




	


-- 

Tell the truth.  Be honest.  Be responsible to and for yourself.



We want our freedoms back.  Strike the illegal legislations called: 1) obamacare, 2) "Patriot (HA!) Act", and 3) 'presidential orders' that affect anyone besides gubmnt worker bees.

Hate crime laws?  Really?  Thought police?  Orwell would be proud.



Every gram of cocaine you buy from elsewhere contributes to an innocent being murdered in Central and South America.  Grow your own or Stop taking it.

nuckolls.bob(at)aeroelect
Guest

Posted: Thu Mar 08, 2012 12:36 pm Post subject: Re-juvinate a NiCad Battery?

At 09:36 AM 3/8/2012, you wrote:

  	  Quote: 	
		  --> AeroElectric-List message posted by: rayj <raymondj(at)frontiernet.net>



 Is it voltage that is measured.  Does the manufacturer supply a voltage vs. % charge graph or table?  Or is it derived experimentally?



 I understand that there are cost/benefit issues here, but my objective is to understand the process from a physics perspective for my own education. 	
  Understand . . .

  I don't think that open circuit terminal voltage has a strong correlation to stored energy on the metal cells. Least wise, I've not seen any charts claiming to offer insight.

    Bob . . .    [quote][b]

nuckolls.bob(at)aeroelect
Guest

Posted: Thu Mar 08, 2012 1:09 pm Post subject: Re-juvinate a NiCad Battery?

or simply putting new cells into the

     device and pitching them when I got home.

  

 I like the second idea.  The reason is the drop in voltage on rechargables is so different from conventional batteries.  One second they look full charged the next second they are dead flat.



   Which goes to my posting a few minutes ago considering an inquiry about voltage versus state of charge on the metal cells. The discharge curves are so flat (and I believe temperature dependent) that the only reliable measure of capacity is to run them down and count the electrons  ------------

  When cheap cells became available on eBay, I

  started dating the new cells when I put them

  in service and pitched them at 6 months.

  The cost of time to test them exceeded the

  value of the cells!

    Now you’re right i don’t like this...  I wish I’d thought of dating the cells because in real terms after six months the really become iffy.  Thanks for the idea.



    Certainly your results may vary. But given that I can buy a metal cell for about the same retail price as a premium pink-bunny battery, I figure if I recharge the things 10 times, I've received more than my money's worth out of them. From that point on, it's gravy and I've got no regrets for pitching a set of cells at first sign of becoming an impediment to completion of task.   ------------  We don’t get any cells (AA) that cheap this far north, wish we did.



    Buy them off eBay. Got any Sam's Clubs around? The Members Mark AA cells are about $13 for a pack of 48 cells. Here's a good mail order source for low cost premium cells



    http://www.batteriesandbutter.com/DUBU.html



   ----------------  The discharge profile of alkaline cells is so different from that of NiCad cells that even a cheap cell is better value than a NiCad especially if you don’t get the advertised 1000 recharges..  BTW did you ever find a person who actually go anywhere near that number of recharges? 



   Don't think so. You might get that kind of result in the lab . . . or maybe that's based on putting partially discharged cells in the charger every night. We know that an SVLA battery is good for about 100 deep discharge cycles under ideal conditions and "thousands" of engine starts when never called upon to supply a lot of energy. I suspect that 1000 cycles thing is more advertising hype than real world performance.



   Worst thing in the world is to leave the batteries with a full charge on it.  If you want to leave a battery for an extended period do so with that battery flat.  That is why when you get a new device the batteries are NEVER charged!  Daily use, especially complete use of batteries is a secret to long life.



   I don't think my experience confirms this. Nickle cells have such high discharge rates that I would be surprised to find anything so equipped to run right out of the box. 



   Now for the best batteries I have ever seen.  They are the batteries that Kodak used to put in their disposable flash cameras.  Most of those batteries only saw a dozen flashes from micro flash units.  So when they came  into the processing lab they were just about full. 



   Do you know that the disposable camera uses a nickle battery? I'd think  they would have to use alkaline or lithium to get any sort of shelf life . . . and yes, running one roll of film through the camera shouldn't even come close to discharging the cell(s).

     Bob . . .    [quote][b]

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