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archive:fun:batteryn.ews

From uwm.edu!spool.mu.edu!agate!stanford.edu!leland.Stanford.EDU!news Fri Nov 13 14:26:07 CST 1992 Article: 8049 of comp.sys.laptops Newsgroups: comp.sys.laptops Path: uwm.edu!spool.mu.edu!agate!stanford.edu!leland.Stanford.EDU!news From: avery@scruffy.neuroinformatik.ruhr-uni-bochum.de (Avery Wang) Subject: Re: NiCad batteries again – useful hints Message-ID: 1992Nov13.092439.11529@leland.Stanford.EDU Sender: news@leland.Stanford.EDU (Mr News) Organization: DSO, Stanford University References: 1992Nov11.030643.21030@schaefer.math.wisc.edu Date: Fri, 13 Nov 92 09:24:39 GMT Lines: 111

Here's something I pulled off the net over 4 years ago – hope it's useful! -Avery


" NICAD BATTERIES - FACTS AND FALLACIES " Published on Radio Communication May 1988, TT.

Richargable nickel cadmium batteries, have, with reasons, become a popular source of power for portable and handportable equipment. They can provide reliable service over many years if due account is taken of their peculiarities. Yet it remain true that many amateurs are failing to appreciate not only the full capabilities but also the limitations of nicad cells used in battery packs.

J.Fielding,ZS5JF,in "Nickel cadmium batteries for amateur radio equipment" (Radio ZS september 1987,pp4-5) provides a useful survey of the facts and foibles of nicads.The following extracts from his article attack some of the common myths and also provide some safety hints.

1) "Rapid charging causes a decline in cell capacity". NOT TRUE provided that the charge is always terminated at a safe point.

2) "You should not charge only partially discharged cells as this causes a loss in capacity." NOT TRUE. It is not necessary to discharge fully nicad batteries before charging. In fact, THE OPPOSITE is true. Repeated partial charging gives an increase in the number of charge/discharge cycles compared with full-discharged cells.

3) "White crystals growing on the tops of nicad cells mean that the seal is faulty and the cell should be scrapped." NOT TRUE. The electrolyte (potassium hydroxide) is extremely searching and can penetrate the seals used in minute quantities. These crystals are potassium carbonate, which is harmless and can be removed with soap and water. The action of the carbon dioxide in the atmosphere reacts with the electrolyte to form the crystals. After removing the crystals, it is recommended that a smear of silicon grease is applied to slow down the growth of new crystals. The amount of electrolyte lost in this way is insignificant.

4) " I have a cell which appears to take a charge, but after the normal charging period the open circuit voltage is very low. I have been told I should throw it away." NOT TRUE. The reason the cell won't take a charge is usually due to minute crystalline growth across the internal electrodes, caused by prolonged storage. A cure that nearly always works is to pass a very high current for very short time through the affected cell. This fuses the internal "whisker". Discharging a large electrolytic capacitor is one method of doing this. But note that in a battery the faulty cell MUST be isolated from the other cells since zapping the complete battery will not usually result in a cure. Charge the capacitor to about 30v and then discharge it through the faulty cell. Several attemps may be required to clear a stubborn cell.

5) "A battery contains a cell with reversed polarity. The only cure is to replace it". NOT TRUE. The reversed cell ca usually be corrected by a similar technique as that given for 4). After re-polarising the cell, the complete battery can be recharged in the normal way. Full capacity can be regained after about five cycles.

6) "A nicad battery should be stored only in a discharged state". NOT TRUE. It can be stored in any state of charge. Due to its inherent self-discharging characteristics it will eventually become fully discharged after a sufficiently long period of storage. To recharge the battery before returning it to service, a "conditioning" charge of 20h at the normal charging rate is recommended. Afterwards charge normally; full capacity can again be expected after about five cycles.

7) "It is not advisable to keep a nicad battery on permanent trickle charge as this causes permanent degradation of the cells". NOT TRUE. So long as the trickle charge current is adjusted correctly, the charge can continue indefinitely without loss in cell capacity. The safe current can usually be obtained from the manufacturer's data, but 0.025C is a reasonable guide (ie. about 100mA for a 4Ah cell and PRO-RATA). This enables the battery to remain fully charged.

ZS5JF also lists seven safety points that should be considered by users:

1) DO NOT short circuit a fully-charged battery. This if prolonged, can cause excessive gas production with the danger of possible rupturing of the sealed case.

2) Nicads contain a caustic electrolyte: this is perfectly safe as long as common sense is used in use and handling of the cells.

3) A nicad can supply a very high current for a short period (a 4Ah cell can supply over 500A for a few seconds). Sufficient thought should be given when selecting a fuse between the battery and the equipment. The connecting wire should be capable of passing enough current to ensure the fuse blows quickly in the event of a short circuit.

4) DO NOT use partially-discharged cells with fully-charged ones to assemble a battery. Assemble the battery with all the cells discharged and then charge them as a battery.

5) DO NOT carry a fully- or partially-charged battery on an aircraft without taking proper safety precautions. A short-circuited battery pack ca be a time bomb in such situations. Consult the relevant IATA regulations or ask at the airline check-in.

6) DO NOT subject battery packs to very high or low temperatures. Never dispose of a battery pack in a fire or throw it out with domestic waste. If it cannot be disposed of properly it is probably best to bury it in the garden in a safe spot.

7) DO NOT discharge battery packs below about 1V per cell, otherwise there is a possibility of cell reversal.

ZS5JF provides a good deal of other information on charging nicad batteries, and gives as a reference a Varta publication of 1982 "Sealed Nickel Cadmium Batteries" from which some of his notes may have been derived. (G3VA)

  1. —=====***=====—-

From uwm.edu!wupost!decwrl!csus.edu!netcomsv!mork!brunette Mon Aug 10 23:18:11 CDT 1992 Article: 9997 of rec.models.rc Xref: uwm.edu rec.models.rc:9997 sci.electronics:38540 Newsgroups: rec.models.rc,sci.electronics Path: uwm.edu!wupost!decwrl!csus.edu!netcomsv!mork!brunette From: brunette@netcom.com (Hal Brunette) Subject: Re: How to dispose of NiCads? Message-ID: p5mmrwq.brunette@netcom.com Date: Tue, 28 Jul 92 20:10:45 GMT Organization: Netcom - Online Communication Services (408 241-9760 guest) References: 1992Jul27.161240.4905@nynexst.com k6lmatq.brunette@netcom.com 1992Jul28.140405.28429@gdunix.gd.chalmers.se Lines: 88

|> D.C. Myers, "Zap New Life into Dead Ni-Cd Batteries," Popular Electronics,
|> July 1977, pp. 60-61.
|>
|> The article explains internal shorts and how to clear them.
If it`s possible, try to rewrite the article in a message here in rec.models.
rc and sci.electronics.

I`m sure many readers here has many NiCd cells they want to restore.

The failures the article talks about occur in mutli-cell Ni-Cd battery packs, and are due to the voltage differences between cells. Say you have four 1.25 V cells in a pack connected to a 200 ohm load. The load "sees" 5 volts and draws 25 mA. Since each cell must pass the entire 25 mA and each cell's potential is 1.25 volts, Ohm's Law tells us that each cell sees the equivalent load of 50 ohms.

But in practice, no four cells in a battery ever exhibit exactly the same output voltage. Assume that one cell is delivering only 1.2 V, and the others are at 1.25 volts. Now, the 200 ohm load sees 4.95 volts and draws 24.75 mA. Since all four cells must pass the entire 24.75 mA, each of the strong cells at 1.25 volts sees an equivalent load of 50.5 ohms; the weak cell sees only 48.5 ohms. The weak cell works into the heaviest load and as a result will discharge more rapidly than the other cells. If the pack is charged for only a short period of time, the weak cell, which has been working the hardest, is also the one that receives the least charging power.

This usually doesn't matter if you trickle charge after each day of flying. The inequality is small for any given charge or discharge cycle, due to the relatively flat output voltage NiCd cells exhibit over most of their range. But a combination of incomplete charges and deep discharges will exaggerate the energy difference between a weak cell and the other cells. Operated continually in this manner, the weak cell invariably reaches its "knee," the point at which its voltage decreases sharply, long before the other cells reach the same point.

Now comes the problem! Suddenly, the weakest cell sees an increasingly heavy load, which causes its voltage to drop even faster. This avalanche continues until the cell is completely discharged, even as the other cells continue to force current to flow. The inevitable result is that the weak cell begins to charge in reverse, which eventually causes an internal short. Once an internal short develops, recharging the cell at the normal rate is futile. The short simply bypasses current around the cells active materials. (Even though the cell is apparently dead, most of its plate material is still intact.) If the small amount of material that forms the short could be removed, the cell would be restored to virtually its original capacity once again.

          300 ohm              Charge
             5W             /  Switch 

20-40 + O—/\/\/\—-o——o o————o————————-o VDC | | |

                    |      Zap             |                         |
                    |      Switch          |                        +|
                    |      ___|___         |                    -----------
                    o------o     o---------o                       -----
                    |                      | +             Shorted   |
    6000 micro-     | +                 -------             Cell     |
    Farad, 40V  _________               |     |                      |
    Capacitor   ---------               |_____| Volt                 |
                    |                      |    meter                |
                    |                      |                         |
    - O-------------o----------------------o-------------------------o

Using the circuit shown, the internal short can be burned away in a few seconds. In operation, energy stored in the capacitor is rapidly discharged through the dead cell to produce the high current necessary to clear the short. Current is then limited by the resistor to a safe charge rate for a small A cell.

Several applications of discharge current are usually necessary to clear a cell. During the "zapping" process, it is a good idea to connect a voltmeter across the cell to monitor results. Momentarily close the normally open pushbutton switch several times to successively zap the cell, allowing sufficient time for the capacitor to charge up between zaps, until the voltage begins to rise. Then, with the toggle switch closed, watch as the potential across the cell climbs to 1.25 volts. If the potential stops before full voltage is reached, some residual short remains and another series of zaps is in order. If you observe no effect whatsoever after several zaps and shorting out the cell and taking an ohmmeter measurement indicates a dead short, the cell is beyond redemption and should be replaced.

Once full cell potential is achieved, remove the charging current and monitor battery voltage. If the cell retains its charge, it can be returned to charge and eventually returned to service. But if the cell slowly discharges with no appreciable load, the residual slight short should be cleared. To do this, short circuit the cell for a few minutes to discharge it, zap again, and recharge it to full capacity.

Good luck.

From uwm.edu!cs.utexas.edu!sun-barr!olivea!uunet!infonode!ingr!b11!naomi!lester Mon Aug 10 23:19:34 CDT 1992 Article: 10011 of rec.models.rc Xref: uwm.edu rec.models.rc:10011 sci.electronics:38596 Path: uwm.edu!cs.utexas.edu!sun-barr!olivea!uunet!infonode!ingr!b11!naomi!lester From: lester@naomi.NoSubdomain.NoDomain (Les Bartel) Newsgroups: rec.models.rc,sci.electronics Subject: Re: How to dispose of NiCads? Message-ID: 1992Jul29.124224.26312@b11.b11.ingr.com Date: 29 Jul 92 12:42:24 GMT References: 1992Jul27.161240.4905@nynexst.com k6lmatq.brunette@netcom.com 1992Jul28.140405.28429@gdunix.gd.chalmers.se p5mmrwq.brunette@netcom.com 1992Jul29.084514@ufps9.unifr.ch Sender: usenet@b11.b11.ingr.com (Usenet Network) Reply-To: lester@naomi.b23b.ingr.com Organization: Dazix, An Intergraph Company Lines: 56

In article 1992Jul29.084514@ufps9.unifr.ch, waeber@ufps9.unifr.ch (Bernard Waeber SIUF) writes:

[Text of 'zapper' deleted]

Maybe not, see below.

Absolutely.

You don't have to remove the cell from the pack (unless it is in parallel with another cell). Just clip the zapper leads to the terminals of the cell. In fact, it seems to me that it may even work without isolating the cell if there is a cell in parallel. The shorted cell should take most of the current, and the non-shorted cell some current as well.

 Bad cell
     |
     v
 ___      ___      ___

–|_|—-|_|—-|_|– | | | | | | | | zapper leads - Les – Les Bartel lester@naomi.b23b.ingr.com Dazix, An Intergraph Company uunet!ingr!b23b!naomi!lester From uwm.edu!wupost!cs.utexas.edu!sun-barr!ames!data.nas.nasa.gov!splatter.nas.nasa.gov!bross Mon Nov 16 22:36:07 CST 1992 Article: 8084 of comp.sys.laptops Newsgroups: comp.sys.laptops Path: uwm.edu!wupost!cs.utexas.edu!sun-barr!ames!data.nas.nasa.gov!splatter.nas.nasa.gov!bross From: bross@splatter.nas.nasa.gov (Wilson S. Ross) Subject: Re: NiCad batteries again Keywords: Storage, interrupted charging References: 1992Nov10.062202.14404@schaefer.math.wisc.edu 1992Nov10.084031.5374@jarvis.csri.toronto.edu 1992Nov11.030643.21030@schaefer.math.wisc.edu 1992Nov11.174659.2467@odin.corp.sgi.com Sender: news@nas.nasa.gov (News Administrator) Organization: NAS Program, NASA Ames Research Center, Moffett Field, CA Date: Tue, 17 Nov 92 03:55:52 GMT Message-ID: 1992Nov17.035552.16083@nas.nasa.gov Lines: 9 My Toshiba battery was force-charged by a friend who has some sort of generic charging equipment. It had reached a point where the machine would not operate at all with the battery - even plugged in. Now it has remained plugged & working for months, i.e, I have overcome the problem of always shuffling batteries for home use. My other battery (still good, I hope) sits on the shelf for when I travel. The 'dead' battery isn't good without the power supply. Bill Ross From uwm.edu!cs.utexas.edu!zaphod.mps.ohio-state.edu!darwin.sura.net!uvaarpa!murdoch!holmes.acc.Virginia.EDU!lch3e Sun Nov 22 15:10:20 CST 1992 Article: 8155 of comp.sys.laptops Newsgroups: rec.video,rec.video.releases,comp.sys.laptops Path: uwm.edu!cs.utexas.edu!zaphod.mps.ohio-state.edu!darwin.sura.net!uvaarpa!murdoch!holmes.acc.Virginia.EDU!lch3e From: lch3e@holmes.acc.Virginia.EDU (Lauren C. Howard) Subject: An easy fix for nicads that REALLY works! Message-ID: 1992Nov22.143820.13596@murdoch.acc.Virginia.EDU Originator: lch3e@holmes.acc.Virginia.EDU Sender: usenet@murdoch.acc.Virginia.EDU Organization: University of Virginia Date: Sun, 22 Nov 1992 14:38:20 GMT Lines: 47 Xref: uwm.edu rec.video:41091 rec.video.releases:3862 comp.sys.laptops:8155 Easy FIX for NICADS that REALLY works! It's simple, it's easy, and it really works well! First reinforce the battery pack (if in one) with clear cellophane tape. Then drop the battery, onto it's side, on the floor from about 6 ft. up. You want it to be a really HARD drop: but don't break the battery. Do this seven or more times for each battery. If it's in a pack, drop the pack so each battery hits the floor seven times. I know this seems crazy, but it DOES work, and well. If it doesn't work the first time, try again; harder! You have nothing to lose, since you'd have to replace the battery anyway. An example: the batteries in my portable printer are 8 years old. They were at the point where even after 24 hours charge, and still plugged into the charger, the printer wouldn't operate. After dropping, I now get three weeks of printing from one charge. So far, it's never failed. What have you got to lose? Post your results so others can benefit, and spread the word! From uwm.edu!zaphod.mps.ohio-state.edu!darwin.sura.net!gatech!destroyer!news.iastate.edu!sknapp Sat Nov 28 14:31:51 CST 1992 Article: 8219 of comp.sys.laptops Newsgroups: comp.sys.laptops Path: uwm.edu!zaphod.mps.ohio-state.edu!darwin.sura.net!gatech!destroyer!news.iastate.edu!sknapp From: sknapp@iastate.edu (Steven M. Knapp) Subject: Re: T1000SE battery replacement (INSTRUCTIONS!) Message-ID: ByF3yp.6Ir@news.iastate.edu Sender: news@news.iastate.edu (USENET News System) Organization: Iowa State University, Ames, IA References: 41667@sdcc12.ucsd.edu Date: Sat, 28 Nov 1992 08:37:36 GMT Lines: 76 In article 41667@sdcc12.ucsd.edu ma90fau@imath1.ucsd.edu (ma90fau) writes: >Sorry if this has been discussed before. On the recent thread, >people has been talking about the Radio Shack's replacement nicad >cell. For people who has done the replacement for T1000SE, can you >give me the detail instructions(what type of cell to use?..etc) to >revitalize my old battery? …. just trying to find a cheap method >to power my cheap notebook… >Thanks! Read me now, or save me for later. (in that imfamous Hans `n' Frans tone) :-) Ok, so you have a T1000SE, and you have found how it does not work if you do not have a good battery on the back. You called Toshiba, and suddenly felt woozy. Aftermarket? Shure! $60 for the T1200XE pack (extended life, the only way to go), but there still has to be a better way, the "college student method"! You call a battery store, and discover that the pack is 'sealed' and can not be rebuilt. Then again, you never did listen to the 'no user serviceable parts inside' lables. The plan? Open it, replace the cells, and close it up. Opening: It is sealed, ultrasound welded actually. All you need to do is break this thin joint. Take the pack off of the computer (back up that hardRAM!) and place it so that the metal contact squares are faceing you and up. The part faceing up, or the bottom of the pack, was physically seprate from the rest of the shell. Note that all 4 metal contact squares are attached to this piece. Now get 2 THIN screwdrivers or knives(jewlers screwdrivers work GREAT). Pick a point that is faceing you (so it will not show when the battery is reinstalled) and push a screwdriver in the small crack/seam between the two pieces. Continue to CAREFULLY pry apart the rest of the seam, and remember, the contact squares are comming all together. After having it all opened, make shure to keep the latch and spring (trust me!). Replacement: Call you local battery distrubitor, or Mr. Nicad, or TNR-The battery store (#'s should be in the 1-800 directory), tell them you got it open. Give them the measurements of one of the cells. I believe they are 4/3A 1700mah, and should be about $5 a shot. Mr NiCad does know them as T1000SE cells last I checked. Get 6 of them. Looking at the old pack, replicate it using the new cells, wire, tape, whatever! DO NOT FORGET THE TEMPRATURE SENSOR! The little black thing attached to one of the cells in the original pack is VERY important! After haveing everything hooked up, you are just about done. Close it up: Check that the contact squares do have voltage around what you would expect (5-7.2V). Reassemble the case, and hold it shut however you see fit. Since I use only one pack, having it on the computer holds it together, and makes it easy to show others my hack. If you have 2 or more, scotch tape should help, or even super-glue. But be warned, you might want to open the pack again some time, and super-glue will make that VERY difficult. There ya go! Good luck! Any questions to sknapp@iastate.edu Flames or insults to /dev/null! I hereby declare this to be advice, use at own risk! I am not responsible for your actions! Steven M. Knapp Computer Engineering Student sknapp@iastate.edu President Cyclone Amateur Radio Club Iowa State University; Ames, IA; USA Durham Center Operations Staff – __ Steven M. Knapp Computer Engineering Student sknapp@iastate.edu President Cyclone Amateur Radio Club Iowa State University; Ames, IA Durham Center Operations Staff

From uwm.edu!cs.utexas.edu!uunet!noc.near.net!news.bbn.com!news.bbn.com!wbe Wed Dec 16 12:28:08 CST 1992 Article: 8462 of comp.sys.laptops Path: uwm.edu!cs.utexas.edu!uunet!noc.near.net!news.bbn.com!news.bbn.com!wbe From: wbe@bbn.com (Winston Edmond) Newsgroups: comp.sys.laptops Subject: Very dead T1000SE battery revived Date: 16 Dec 92 03:01:31 Organization: Bolt Beranek and Newman, Inc., Cambridge, MA Lines: 87 Distribution: world Message-ID: WBE.92Dec16030131@crystal.bbn.com NNTP-Posting-Host: crystal.bbn.com

 Thanks to suggestions from this newsgroup, and after some experimenting, I

seem to have managed to revive a completely dead T1000SE battery pack. The message rambles a bit so that others that have experienced the same problem may compare the solution I found with others that have been discussed in this newsgroup.

Completely dead battery = 0V output, 0 Ohms resistance, regardless of how

long it was "charged" on a T1000SE.

Current state = 7.2V output, and it just powered my T1000SE for 75 minutes

from full charge (green light) to first low charge beep, while
running the screen at medium brightness and using the 2400 bps modem.

Yes, 75 minutes isn't as good as new, but this is the first full charge/discharge cycle after revival, so I don't yet know if it will get better with proper use, or get worse again.

BACKGROUND (how I got into this mess and what didn't work):

 My problem started when the battery pack began running out of power much

sooner than it "should have". I tried deep discharging, dropping the battery pack from a moderately high distance (and other forms of physical bashing that some people thought might help), and various other tricks over the course of time. At first, these seemed to help slightly, but the improvements were only temporary.

 Eventually, while using an auto light bulb to discharge the battery pack,

I forgot the advice to not go below 1 Volt and let the pack discharge completely. After trying to recharge it, I could get the green light to come on, but the system would INSTANTLY shut down if the wall-plug power unit was unplugged. A Voltmeter showed that the battery was only putting out 4.8V. (NOTE: the green light doesn't mean the battery pack is fully charged – it means the battery pack isn't likely to accept any more charge, and that only means "fully charged" if all the cells are working.)

 Continued attempts to revive the battery pack eventually left me with a

battery pack in which all cells were "dead" (in "cell reversal" mode, I think, but I don't understand NiCads well enough to be sure) – 0V, 0 Ohms resistance, immune to all the simple attempts I tried to charge it.

WHAT DID WORK:

 Someone on this newsgroup suggested using a large electrolytic capacitor

charged to 8V and discharged through a completely discharged battery pack. I didn't have a big enough electrolytic capacitor to do the job, so I tried two alternatives: (1) another battery pack, and (2) an industrial power supply capable of supplying 10 Volts at 10 Amps.

 Partial success was obtained by connecting a working, fully charged

battery pack's + to the now-completely-dead battery pack's +, and - to -, with just wires, for a few seconds. This produces a modestly bright spark. Using a second battery pack was good enough to revive 4 of the 6 NiCad cells in the pack, but wasn't enough to bring back the last two. It might have been enough if I'd put some regular batteries in series (and in parallel) to get the voltage and current capacity up a bit.

 The first industrial power supply I tried could only provide up to 5A at

up to 10V. This wasn't enough.

 The second power supply I tried could supply 10A at up to 20V, and 10A at

just 10-12V was enough. The power supply was a high grade unit with adjustable current and voltage limits. I connected + to +, - to -, and let 10A at 12V flow through the battery for a few seconds. That brought the battery pack back up to a full 7.2V! The rest of the charging I did on the T1000SE, because I think feeding 120W into a few NiCad batteries for more than a few seconds at a time is unwise. :-)

DISCLAIMER:

 This message provides history and opinions, not advice.  If you elect to
 try to duplicate this success, you do so at your own risk.  I did find
 that a Voltmeter for measuring the battery pack voltage (which was always
 N * 1.2V) was indispensible.

COMMENTS ON OTHER SOLUTIONS (given what worked for me): * The big electrolytic capacitor method probably would work, though it might

  take several "zaps".

* Using a 12V car battery probably also works, but is overkill and looks to

  be much more dangerous since the current isn't limited and it probably
  causes sparks.  (The bench supply I used caused no sparks when I touched
  the probes to the battery pack, even though it instantly went between 0A
  and 10A output.)

* Connecting up a set of 7 1.5V dry cells (or 9 1.2V NiCad cells) in series

  to get 10+V, probably with N >= 2 sets in parallel to get sufficient
  amperage, should also be able to do the job.  I don't know of anyone
  that's tried this, though.

-WBE

From uwm.edu!cs.utexas.edu!uunet!mcsun!sun4nl!echelon!kees Wed Dec 16 14:55:59 CST 1992 Article: 8465 of comp.sys.laptops Newsgroups: comp.sys.laptops Path: uwm.edu!cs.utexas.edu!uunet!mcsun!sun4nl!echelon!kees From: kees@echelon.uucp (Kees Hendrikse) Subject: Re: Very dead T1000SE battery revived Organization: Echelon Consultancy, Enschede, The Netherlands Date: Wed, 16 Dec 1992 13:44:06 GMT Message-ID: BzCu5J.3Kv@echelon.uucp References: WBE.92Dec16030131@crystal.bbn.com Lines: 22

In WBE.92Dec16030131@crystal.bbn.com wbe@bbn.com (Winston Edmond) writes:

Thanks to suggestions from this newsgroup, and after some experimenting, I
seem to have managed to revive a completely dead T1000SE battery pack.

After writing how he did manage to revive the NiCad, Winston Edmond suggest other ways to do it, including:

* Using a 12V car battery probably also works, but is overkill and looks to
be much more dangerous since the current isn't limited and it probably
causes sparks.

Never ever try this suggestion, as a car battery (especially a healthy one) is capable of delivering 70-80 Amps through the NiCad, which might cause the NiCad to explode. Always use a device with controlled current. If you can't revive the NiCad with about 10 Amps, throw it away, it's really dead.

– Kees Hendrikse | email: kees@echelon.uucp

                                            |

ECHELON consultancy and software development | phone: +31 (0)53 836 585 PO Box 545, 7500AM Enschede, The Netherlands | fax: +31 (0)53 337 415

From uwm.edu!zaphod.mps.ohio-state.edu!uunet.ca!synapse!peter.latocki Fri Dec 25 17:33:02 CST 1992 Article: 8578 of comp.sys.laptops Path: uwm.edu!zaphod.mps.ohio-state.edu!uunet.ca!synapse!peter.latocki From: peter.latocki@synapse.org (Peter Latocki) Newsgroups: comp.sys.laptops Subject: Battert for Old T1000 Message-ID: 1677.2411.uupcb@synapse.org Date: 25 Dec 92 08:53:00 GMT Distribution: world Organization: SYNAPSE BBS - GATINEAU, QUEBEC - 819-561-4321 Reply-To: peter.latocki@synapse.org (Peter Latocki) Lines: 13

TO:gaston@cpsc.ucalgary.ca FROM:peter.latocki@synapse.org

I picked up a battery for my T1000 at Battery-Biz, 5530 Corbin Ave. Suite 215 Tarzana California 91356 (818)774-1678 or (800)848-6782 a year and a half ago. It sold for $18 and the people there were very nice to deal with. Also try contacting Toshibs Canada for memory etc. They were recently listing the RAM upgrade for the old T1000 for $79 but you have to order through a dealer. Call their Fax line at 1-800-663-0378 to have a copy of their price list faxed to you. — . SLMR 2.1a . Unable to locate Coffee – Operator Halted!

From uwm.edu!spool.mu.edu!torn!skule.ecf!drill.me!ie.utoronto.ca!xiao Wed Jan 20 15:38:22 CST 1993 Article: 8834 of comp.sys.laptops Newsgroups: comp.sys.laptops Path: uwm.edu!spool.mu.edu!torn!skule.ecf!drill.me!ie.utoronto.ca!xiao From: xiao@ie.utoronto.ca (Yan Xiao) Subject: Another successful story of nursing dead battery Message-ID: C15t88.12n@ie.utoronto.ca Summary: Open it up, find the bad cell, reverse its polarity, DONE Keywords: plyers, fainted Organization: University of Toronto, Department of Industrial Engineering Date: Wed, 20 Jan 1993 15:48:07 GMT Lines: 23

Here is my experience of fixing a dead batter.

Problem: the battery won't hold any charge, but can be used when AC plug

is in (so what's the use of the laptop)

Hypothesis: The polarity of one of the cells is reversed somehow.

Treatment one: use a car battery to reverse the bad cell

potential side effect: explosion

Treatment two: open it up and check for bad cell to see if it can be fixed.

side effect: breaking the nice outfit

I chose the second method. It required a little resolution to open

the battery case (T1000SE), but not too bad.
Using a simple flashlight bulb, I located the
bad cell.  Then I used another 7.2v battery to apply to this
cell, and verified its working by the flashlight.
I had to use tape to bound the battery in good solid condition.

Results: it now can holds about 90min of charge.

Xiao

From uwm.edu!spool.mu.edu!sol.ctr.columbia.edu!usenet.ucs.indiana.edu!silver.ucs.indiana.edu!wilkr Thu Jan 21 22:06:51 CST 1993 Article: 8854 of comp.sys.laptops Newsgroups: comp.sys.laptops Path: uwm.edu!spool.mu.edu!sol.ctr.columbia.edu!usenet.ucs.indiana.edu!silver.ucs.indiana.edu!wilkr From: wilkr@silver.ucs.indiana.edu (richard wilk) Subject: Ideas & Help needed: Running Laptop from Car Battery Message-ID: C17yvt.9Ft@usenet.ucs.indiana.edu Summary: How can this be done??? Sender: Richard Wilk (wilkr@iubacs, wilkr@ucs.indiana.edu) Nntp-Posting-Host: silver.ucs.indiana.edu Organization: Indiana University Date: Thu, 21 Jan 1993 19:45:28 GMT Lines: 53

I need some feedback, advice and tech help on the following problem.

I will be spending the summer living in a tent in Central America, miles from the nearest power line. I will be spending most of my time writing on my no-name clone 386SX laptop. This uses a fairly standard 12V nicad battery, and generally gives me about 1.25 hours.

I have located a couple of photo-volataic trickle-chargers which will take about 8 hours to charge my battery (the cheapest one I have found is from a company in Ann Arbor, at 313 453-6746 if you are interested). But this will only give me an hour of writing a day.

We have the money to buy a 4000 watt coleman generator (best price so far about $425), but not enough money to run it more than 2-3 hours a night (and who wants the noise anyway). We may have enough also for a small PV array, but I don't know how large or what wattage.

I am presently thinking about buying a car battery down there, a battery charger, and an inverter. Then I would charge the car battery every night, and run the computer off it through the inverter the next day. Damark has a 100 watt inverter for sale right now for c. $70.

Questions: Will this work? Has anyone tried something similar?

Sub-questions: How long do I have to run the generator to get the battery charged?

How big a PV array would I need to replace the generator completely? (we will be running a few lights and radios in the evenings too)

How many hours of use can I expect to get out of a car battery if the computer is drawing about 45 watts (I *think* that is what the manual says).

Does it make any sense at all to be going from 110 volts AC (battery charger) to 12 Volts DC (battery) to 110 volts AC (inverter, computer power supply) to 12 Volts DC (computer power jack)????? Is there any way to feed the computer, safely, straight from the car battery??

I would appreciate hearing from anyone with experience, ideas or knowledge (there must be someone with all three).

Thanks very much

Rick Wilk

– Richard Wilk Anthropology Dept. wilkr@iubacs Indiana University voice 812-855-8162 Bloomington, IN 47405 "Things are more like they are now than they've ever been before."

From uwm.edu!cs.utexas.edu!sun-barr!olivea!sgigate!sgiblab!pacbell.com!att-out!cbnewsh!colin Fri Jan 22 21:27:51 CST 1993 Article: 4811 of comp.sys.palmtops Path: uwm.edu!cs.utexas.edu!sun-barr!olivea!sgigate!sgiblab!pacbell.com!att-out!cbnewsh!colin From: colin@cbnewsh.cb.att.com (colin.alan.warwick) Newsgroups: comp.sys.palmtops,sci.physics Subject: Nickel metal hydride cells in standard form factors Message-ID: 1993Jan22.195301.22212@cbnewsh.cb.att.com Date: 22 Jan 93 19:53:01 GMT Followup-To: poster Distribution: usa Organization: AT&T Bell Laboratories - Holmdel NJ Lines: 25 Xref: uwm.edu comp.sys.palmtops:4811 sci.physics:46685

Does anyone have data on nickel metal hydride rechargable cells in standard form factors?

I'd like to populate a table like:

Form Charge Price factor (mA hr) ($)

AAA ??? ??? AA ??? ??? C ??? ??? D ??? ???

[What ever happened to A and B cells?]

Also, what is the voltage of a fully charged NiMH cell, under a moderate load?

Thanx,

colin.alan.warwick@att.com

"This is a talk on experimental mathematics, and if that sounds like a contradiction, it is no more so than `theoretical physics'."

  1. - F. N. H. Robinson.

From uwm.edu!spool.mu.edu!yale.edu!newsserver.jvnc.net!darwin.sura.net!ukma!cs.widener.edu!iggy.GW.Vitalink.COM!nocsun.NOC.Vitalink.COM!indetech!cirrus!pete Tue Feb 9 11:47:44 CST 1993 Article: 5050 of comp.sys.palmtops Newsgroups: comp.sys.palmtops Path: uwm.edu!spool.mu.edu!yale.edu!newsserver.jvnc.net!darwin.sura.net!ukma!cs.widener.edu!iggy.GW.Vitalink.COM!nocsun.NOC.Vitalink.COM!indetech!cirrus!pete From: pete@cirrus.com (Pete Carpenter) Subject: Nickel Hydride Sources Message-ID: 1993Feb8.224131.24812@cirrus.com Sender: news@cirrus.com Organization: Cirrus Logic Inc. Fremont, California Date: Mon, 8 Feb 1993 22:41:31 GMT Lines: 50

These two companies sell Nickel Hydride batteries. Both sell AA and C sizes, and both cost exactly the same (Hmmmm) They call themselves "Alternative Energy" suppliers, which means they sell solar (photovoltaic or PV) panels, and other stuff like 12 VDC to 120 VAC inverters, etc. I've bought lots of stuff from both.


SUNELCO 100 Skeets St. P.O. Box 1499 Hamilton, MT 59840-1499 order 800-338-6844 info 406-363-6924 fax 406-363-6046

catalog size amp-hr price


NI-AAHY AA 1.0 AH $ 8 NI-CHY C 3.5 AH $16


Real Goods likes to wear their politics on their sleave, so to speak. If you think Clinton may ruin the world by being too _conservative_, you'll fit right in :-) I like their merchandise, not their preaching.

Real Goods 966 Mazzoni St. Ukiah, CA 95482-3471 800-762-7325

50-105 AA 1.1 AH $ 8 50-104 C 3.5 AH $16

catalog includes this statement - "a little fatter than AA batteries, may not fit in very tight spaces"


I got some AAs from Real Goods, and they fit in my ZEOS, but unfortunately, I can't get them to work. Voltage is 1.35, same to Radio Shack AA NiCd.s, which work fine.

– Pete Carpenter pete@cirrus.com

Talk about your plenty, talk about your ills, One man gathers what another man spills. - Robert Hunter

From uwm.edu!spool.mu.edu!hri.com!noc.near.net!news.bbn.com!bbn.com!sher Wed Feb 24 13:53:02 CST 1993 Article: 9312 of comp.sys.laptops Path: uwm.edu!spool.mu.edu!hri.com!noc.near.net!news.bbn.com!bbn.com!sher From: sher@bbn.com (Lawrence D. Sher) Newsgroups: comp.sys.laptops Subject: Re: T1000SE battery life Message-ID: lomtcaINN2jo@news.bbn.com Date: 24 Feb 93 13:18:02 GMT References: 1993Feb23.201949.858@nas.nasa.gov Organization: Bolt Beranek and Newman Inc., Cambridge MA Lines: 66 NNTP-Posting-Host: bbn.com

In article 1993Feb23.201949.858@nas.nasa.gov proett@tailspin.nas.nasa.gov (Tom Proett) writes:

Hi,

I have a T1000SE which has a problem with the battery. It will only
work when it is plugged in now. If I try to unplug it, it will
shut down right away. I took the battery out and hooked it to a
flashlight bulb to drain it. It lighted the bulb brightly for
just under 6 hours. I charged it again and it still would not work.

Is there a setting on the computer itself which tells it to not shut
down? It seems that the battery is at least fairly good if it can
light a light for more than 5 hours.

Thanks.


proett@tailspin.nas.nasa.gov
NASA Ames Research Center

This seems to be a common problem. I don't know any definitive answers, but since I faced the same problem, I had occasion to look into it.

1. Buy replacement cells, open the pack, and put in the new cells. A good source for replacement cells (in New England): Gates Energy Products, Inc. 1 Prestige Drive, Meriden, CT 06450-7105 Tel: (203) 238 6912, FAX (203) 238 6887 Voice Mail: (904) 462 8725. Attention: David Childs, sales engineer, Northern Sales Region. He was very helpful for me. The cells to get: GLF-1700A Ultramax NiCad. (The cell size, officially, is 4/3A.) Cell cost is around $5.50-6.00 as I recall.

Opening the pack requires a careful dissection along the ultrasonically welded perimeter seam, visible with the pack upside down. You can put it back together again with glue of various flavors. Be sure to put back the temperature sensor that is nestled in between two of the cells.

2. Exhume the existing cell(s). Once the pack was open, I found one cell that was weak (discharged quickly) and one that was zero volts, zero ohms. (Even so, of course, the remaining cells would easily run most flashlight bulbs.) Taking a cue from various other posters ("put a good cell in parallel with the bad one", "discharge a capacitor into the bad cell") and feeling I had little to lose, I decided that if a little was good, more would be better. So I connected a 12v automobile battery charger across each bad cell (one at a time). I set the current level to "trickle", connected positive-to-positive, negative-to-negative, and turned on the power for about 3 seconds. Scarey! Longer connections obvious raise the ante, like inadvertent explosions. An ammeter (on the charger) showed currents exceeding 10 amperes, tending to decay over a few seconds to less than 10 amperes, but I wasn't about to get too academic about this. A voltmeter showed 0 volts before the treatment and 1.2+ after. I repeated this treatment about 3 times, with a respectful interval in between, like a minute. Voila, the cell now looked normal, with an open circuit voltage of about 1.3. I put everything back together, let the Toshiba charger care for the pack overnight, and the next morning, it all seemed to run fine.

Note: I first tried this treatment across several cells in series, only one of which was bad. It did not help!

I can hardly guarantee the safety or long-term consequences of this procedure. But, clearly, there is some rationale to the talk that a sufficient goosing of these cells can exhume them.

           .---------------------------------------------------------------- 
          /Internet email: sher@bbn.com

Larry Sher < US Mail: BBN, MS 6/5A, 10 Moulton St., Cambridge, MA 02138

          \     Telephone: (617) 873 3426    FAX: (617) 873 3776
     `----------------------------------------------------------------

From uwm.edu!cs.utexas.edu!uunet!ehbbs!joe.george Sun Mar 7 15:29:10 CST 1993 Article: 5584 of comp.sys.palmtops Path: uwm.edu!cs.utexas.edu!uunet!ehbbs!joe.george From: joe.george@ehbbs.com (Joe George) Newsgroups: comp.sys.palmtops Subject: HP95LX batteries ? Message-ID: 1436.616.uupcb@ehbbs.com Date: 5 Mar 93 23:01:00 GMT Distribution: world Organization: Ed Hopper's BBS - Berkeley Lake, GA - 404-446-9462 Reply-To: joe.george@ehbbs.com (Joe George) Lines: 26

SDFW→ What does the '95LX use for batteries ?

Just about any AA batteries work, with varying results. The HP's internal battery-level meter is geared to the steady voltage dropoff of alkaline batteries; the reason NiCd batteries stink out loud in equipment like this is that when NiCds run out of gas, the voltage drop off is quick and very steep and _very_ unforgiving. I've not used NiMH batteries in my HP (but I have one in my laptop, it's got a lot longer life but an odd voltage drop off. Not bad, just odd.)

The batteries I now exclusively use in my HP are Eveready Energizer High-Energy Lithium AA Batteries. Theyre about $1.50 a pair more expensive than standard Energizers but I get 2-3x the life out of them. They, too, have a kind of quick drop off (I ran for 3 weeks with the battery meter on "Full" and went down to "Empty" in a matter of 2 days)

Joe

* SLMR 2.1a * TV is a medium; anything well done is rare.

—- +—————————————————————————+

Ed Hopper's BBS - ehbbs.com - Berkeley Lake (Atlanta), Georgia
USR/HST:404-446-9462 V.32bis:404-446-9465-Home of uuPCB Usenet for PC Board

+—————————————————————————+

From uwm.edu!wupost!howland.reston.ans.net!gatech!news.ans.net!cmcl2!netnews!jan.ultra.nyu.edu!edler Wed Apr 21 15:28:17 CDT 1993 Article: 10220 of comp.sys.laptops Path: uwm.edu!wupost!howland.reston.ans.net!gatech!news.ans.net!cmcl2!netnews!jan.ultra.nyu.edu!edler From: edler@jan.ultra.nyu.edu (Jan Edler) Newsgroups: comp.sys.laptops Subject: Re: Getting rid of Nicad memory effect Date: 19 Apr 1993 17:57:14 GMT Organization: New York University, Ultracomputer project Lines: 27 Message-ID: 1qup5q$scs@calvin.NYU.EDU References: 735092474snx@tixel.mv.com NNTP-Posting-Host: jan.ultra.nyu.edu

In article 735092474snx@tixel.mv.com jarnold@tixel.mv.com writes:

I had posted a note a few weeks ago about how to "fully discharge" a
nicad battery pack (that powers my notebook pc) that has apparently
developed the dreaded nicad memory effect. Brand new, I used to be
able to get 3+ hours of heads-down work out of a charge, but now
(same apps, same work habits) I'm lucky to get as much as *one* hour.

I have been using a resistor to regularly discharge my T1000SE battery for several years. This is a 7.2V pack. I use a 10 Ohm power resistor from Radio Shack. I remove the battery, place it upside down, place the resistor on the battery contacts (I've bent the resistor's leads to make this convenient), and put a little weight on it to make a good connection. I normally connect a voltmeter to it, and wait about 10 or 12 minutes for the voltage to drop below 6V. I keep the voltmeter on my desk, so this is convenient, but otherwise I just time it for about 10 minutes. I use a kitchen timer to remind me when to check the battery. I go through this procedure almost every time the machine shuts off, before recharging (i.e., about daily). This arrangement seems to work well.

When I started doing this, a few years ago, I drained the battery all the way (until the resistor was cold). I never had any trouble, but various people were making arguments that this could damage the cells, so now I stop somewhere below 6V. So far so good.

Jan Edler edler@nyu.edu

From uwm.edu!cs.utexas.edu!uunet!olivea!charnel!csusac!sactoh0!mnj Tue May 18 14:40:39 CDT 1993 Article: 14012 of comp.sys.handhelds Newsgroups: comp.sys.handhelds Path: uwm.edu!cs.utexas.edu!uunet!olivea!charnel!csusac!sactoh0!mnj From: mnj@sactoh0.sac.ca.us (Mark Newton-John) Subject: Re: Batteries for the Psion Series 3 Message-ID: 1993May18.083859.12296@sactoh0.sac.ca.us Organization: Sacramento Public Access Unix References: 1993May17.143707.7032@unix.brighton.ac.uk Date: Tue, 18 May 93 08:38:59 GMT Lines: 29

In 1993May17.143707.7032@unix.brighton.ac.uk ah57@unix.brighton.ac.uk (Andrew) writes:

Has anybody found it possible to use rechargeable batteries in their
Psion Series3? I Have tried using rechargeables but they seem only to last
for about a day before I get lots of Main battery is low warnings.

The problem with rechargeables is that they are not the 1.5 volts that regular alkalines give. (typically 1.2 volts)

The Psion sees the low voltage and will give the low battery warning, and if ignored, will start to use the memory battery.

With the Portfolio, what can happen is that the low battery warning could be missed, and when the power falls off (rechargebles fall off rapidly) memory loss will occur.

The best batteries that I have found to use in handhelds are Maxell (yes, the tape company) Photo AA (LR6) alkalines. They are a more powerfull alkaline, designed for high drain useage in camera flashes and motor drives. They are $3.49 per 4-pack. They have outlasted a set of Energizers (stupid rabbit) and Duracells.

– mfolivo@sactoh0.SAC.CA.US SAC-UNIX (916) 649-0161 The Good Guys! We know our stuff Audi The Alternate Route Atari Power without the Price

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