Reviving old NiCd batteries

[hrhofmann]

If you short an individual ccell, the volatge is force to zero. If you short a battery pack, you may actually put a reverse voltage on some of the weaker sells. They don't like this at all!.

[clare]

I did not say powersonic said that., did I? I said , and I quote," There are also other references that talk about storing Nicads shorted "

And ALL I said was "panasonic says"

Well, just going from my experience with Nicad powered tools - and this is far from definitive, I'll admit - batteries that have been left without a charge for more than 4 months were DEAD when I went to use them - and if I left them for a year, in most cases they were shorted when I tried to recharge them. A good ZAP would make them take a charge, but the next time I needed the tool, the battery was invariably dead again - and often again had at least 1 shorted cell. On the one unit that I used on a semi-regular basis - charging every couple of months - the battery lasted about twice as long before failing.( I got better than 4 years out of that one drill battery - whils the other drills and the saw ALL failed within 2 years.

I just finally threw all the drills away and bought a Lithium powered drill. I still have the recip saw - but the batteries are pretty well shot after having been rebuilt once. Won't waste my money on a second go-round.

Personally, I've pretty well given up on NiCads.

[clare]

Correct.

[trader4]

If that is correct, then how can you be saying that those that say to store Nicads discharged recommend doing it? You've contradicted yourself. But it doesn't matter, because I've already given you several sources that say to store them discharged, all are clearly talking about more than one cell, and none of them say what you claim.

[trader4]

I've used a Milwaukee driver drill that's 20+ years old and used the nicad battery pack in that very rarely, maybe once every 2 years. Just put it away in whatever condition it was in when I was done. Over the last 10 years, the charge level it would hold decreased, but it was still enought to do the limited amount of work I used it for. At 20 years, I was still getting

5 mins or so of work out of it. Last year, when I went to use it, it would not hold a charge at all. So, I bought new batteries on Ebay and rebuilt the pack.

[clare]

:

>

IF you store them dead, they should be stored shorted. That's what several sources are saying - and if you store them shorted they MUST be shorted individually - which means storing batteries - not cells, SHOULD be done charged.

Yes, you will find all kinds of recommendations - many of which will contradict each other. And yes, you may get away with storing batteries (not cells) dead and open circuit - and you might get away with storing totally dead batteries (not cells) shorted - but it is not recommended "best practice" and the gremlins are out there waiting for you. Storing "dead" batteries shorted CAN cause cell reversal - and cell reversal is NOT good for the battery, or the individual cell. Same with single cells - storing dead and open circuit might work for you - but it is not "best practice"

[trader4]

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You keep going back and forth here. You seem to imply there is agreement from many sources. When that doesn't pan out, then you claimed you were just citing what Panasonic says. I'd like to see the several sources that you have which say the above. IMO, it sounds crazy because from a practical standpoint, virtually all the nicads we deal with are going to be multiple cell. And I gave you several sources, including manufacturing Power-Sonic that say to store them discharged. I highly doubt PS expects you to tear apart the battery to discharge and then short each cell individually.

What makes it "best practice". Just because Panasonic, one manufacturer, recommends it, doesn't mean that is absolute and correct. As I pointed out, Panasonic does not even explain what their concern is. Other sources that say to store them discharge say that if they are stored charged and allowed to discharge, it may result in them having to be cycled several times later to get them back to holding a full charge. For all we know, that temporary issue is what Panasonic is talking about. The sources I've seen that go into the technical details of how the batteries work tend to say that they should be stored discharged. And again, if what you claim above is true, it would be pretty stupid for them to keep stating that they really mean you must tear open the batteries and short each cell individually.

Again, from the start, I said there are a variety of opinions out there. For some reason, you seem to believe only Panasonic. That's fine, you can do as you want. The only issue I have is you keep trying to make it sound like that is the only right way and Panny's opinion is golden.

You're the one who brought storing batteries shorted into the discussion. The sources I provided that talk about storage say to store them discharged or partially discharged.

[clare]

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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 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.

[Robert Green]

FWIW, I still have about 20 Lafayette hi-cap NiCads that were always stored fully charged that still take and hold a charge. I've had cheap Chinese batteries fail no matter which way they were stored. I've also tried the whisker burning zapping method but the cells would never work as well as unwhiskered cells afterwards. The damn whiskers would ALWAYS grow back.

I finally got a LaCrosse charger with an LCD readout of charge rates, voltage, amount of charge taken, etc. for each individual battery (it holds four AA/AAA's. When a cell turns up bad (i.e. takes 3Ah of charge instead of

800mAh) into the trash it goes. Life's too short to risk injury from zapping. I had an AAA NiCad cell explode with the force of a .22LR. That was that for zapping. I found myself asking "are you so damn cheap you can't throw away a bad battery?"

I also test cells by charging them up and bagging them with a date on them. A month or two later I discard all the cells that show under 1 volt. I've had some interesting results with the newer NiMH batteries that can hold 80% of their charge for a year. Oddly, the expensive Enerloop batteries fared much worse in my tests than the much cheaper AC/Delco version. Go figure. I'm guessing that each battery maker uses slightly different "goo" and manufacturing techniques and one size/method of charging does NOT fit all.

I might try adding "drained and shorted" to some of what my wife fondly calls "my science projects" but I've largely stopped using individual NiCad cells for anything. Not enough power or longevity of charge compared to NiMH. The new AC/Delco's seem to be ideal for things that tend to get accidentally left on.

-- Bobby G.

[trader4]

At least I've cited multiple credible sources that disagree with Panasonic. 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. 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. 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.

[clare]

What part of "You don't have to agree with me, but that's what I've always been taught - and from  what I gather from the very limited information on the net, nothing has changed my mind." do you not understand?

There is not enough definitive information on the net to establish what is correct - or if there is, in fact, any REAL difference. Over the years I've been taught you keep them charged, but not on float, if you cannot store them DEAD and shorted - and you NEVER short a string of cells in series.

Shorted dead strings are OUT due to the danger of cell reversal. 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.

[RicodJour]

Interesting. I like the computer power supply idea. The part I don't like is that last weekend I brought all of the electronic recyclable stuff to the recycling center dropoff. Hmmm, I wonder who's not using their computer around here....? ;)

Thanks for the info and idea.

R

[trader4]

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.

The part where you then proceed to claim that the " best practice" is not to store them discharged.

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.

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.

[krw]

It's not like you have a choice. They *are* going to self-discharge anyway. The worst possible condition is to store NiCds on a constant charge. Storing them discharged is the only other possibility. ;-)

Shorting *any* battery is a dumb thing to do.

[clare]

You will want an older xt/at style supply, not the newer ATX, if you want it to be "simple"

[clare]

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.

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 here:

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.

[Gz]

For the record, zapping will only temporally fix cells. Charging them making them warm all the time is very bad. I charge my Johnson nicads, almost 50 years old, once every 2 or 3 years, and the receiver always works.

Greg

[clare]

You are correct - it's not rocket science - but the old XT/AT supplies were also significantly more reliable. LOTS of them still going strong at 20 years of age, while the "average" ATX supply is toast in less than 10 - many not lasting 2.

[clare]

Sadly, when it comes to those old nicads - they just do NOT make them like that any more!!!!

[The Daring Dufas]

Yea, the original IBM PC made in America was built like a tank with high quality components which is why the darn things cost 4-5 thousand dollars back then. :-)

TDD