Battery memory on NiCad cordless drill

Aug 05, 2006 49 Replies

Nonsense. NiCDs and NiMH batteries love to be discharged. That's the only way to store them for long periods. Don't "reverse charge" cell(s) in a multi-cell battery by discharging it below about 1V/cell though. They can be left to self discharge without damage. A single cell battery can be discharged to zero.

OTOH, lead-acid batteries must never be fully discharged and must be stored with a float charge. Lead-acid batteries are thus better for things like flashlights, UPSs, safety lighting, and such.

Not any more. NiCds may be 20% per month, usually less. NiMH has gotten a lot better too, but it was never as bad as 10% per day.

Would you have any evidence for this article of faith? :-)

Nick

Dan_Musicant wrote in news: snipped-for-privacy@4ax.com:

the NiCds in my B&D Dustbuster lasted 10 yrs,but they were a type designed to stay on the charger all the time when not in use. I had a local DeWalt service center replace the 4-cell pack because it was cheaper than buying a new DB.

My first set of Makita 9.6V sticks lasted 7-8 yrs bacause they were used often and kept charged. When I ceased using them regularly,they quickly failed,even maintaining their charge.Same for my B&D VersaPack 3.6v screwdriver packs.

Keith Williams wrote in news: snipped-for-privacy@News.Individual.NET:

Agreed.

That's wrong. They should be stored CHARGED. Do you have any cites for your claim?

NiCd Figures I've seen are ~5% self-discharge/day. Storage temperature greatly affects this.

I have seen datasheets for NiMH cells indicating that the self discharge rate decreases as self discharge progresses. A cell could self-discharge

5% in a day but less than 20% in a week. I would suspect NiCd can do something similar.

- Don Klipstein ( snipped-for-privacy@misty.com)

"werty" wrote in news: snipped-for-privacy@m73g2000cwd.googlegroups.com:

It is less painful to buy new batteries than read that post :-)

Yes, Gates' secondary battery manual. The chemical reaction stops with zero terminal voltage. They store quite nicely that way. In any case, they *will* self discharge and the worse thing possible for a NiCd or NiMH is to float charge it. THis is exactly the opposite as is the situation for Lead-acid cells.

Nonsense. They do *not* self discharge totally in a month. ...more like 20% a month. Classically NiMH self-discharges at about twice the rate of NiCD, but AIUI they've gotten much closer.

With my Johnson walkie talkies with the42 year old NiCads, i charge some every year or two. I have never found them totally dead.

greg

snipped-for-privacy@pitt.edu (GregS) wrote in news:ebi0vc$air$ snipped-for-privacy@usenet01.srv.cis.pitt.edu:

Well! that certainly proves something.

???

:Dan_Musicant wrote in :news: snipped-for-privacy@4ax.com: : :> On 6 Aug 2006 05:58:34 -0400, snipped-for-privacy@ece.villanova.edu wrote: :> :>:JimL wrote: :>: :>:> Four years is past the maximum life of a nicad even you you have :>:>only used them lightly. :>: :>:Maybe my 10-year-old nicads never read the book :-) :> :> Indeed, I have NiCads that must be 8+ years old, are in many seasons :> very very seldom used and they seem to be reasonably adequate. I suspect :> I can revive my drill NiCads. I'm not shopping just yet. :> :> Dan :> : :the NiCds in my B&D Dustbuster lasted 10 yrs,but they were a type designed :to stay on the charger all the time when not in use. :I had a local DeWalt service center replace the 4-cell pack because it was :cheaper than buying a new DB. : :My first set of Makita 9.6V sticks lasted 7-8 yrs bacause they were used :often and kept charged. :When I ceased using them regularly,they quickly failed,even maintaining :their charge.Same for my B&D VersaPack 3.6v screwdriver packs.

I have quite a few of those B&D VersaPack 3.6v screwdriver packs, and don't use them much. I suppose there's nothing I can do to prevent the batteries from dying early. I must have about 8 of those batteries. They are mostly less than 2 years old.

Dan

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