help! laptop's CMOS battery is dying

Hi all,

My CMOS battery -- also called the Backup Battery or the RTF battery -- is dying. When I power up my Thinkpad I will occassionally get error codes indicating that the battery is not present or that the CMOS has been erased.

Today at one point when I tried to power up the computer didn't even respond--despite the NiMH battery being good-- until I plugging in the AC power.

So I've been shopping for a replacement for this specific CMOS battery (FRU 12J1695) but I am finding few places that have the original.

Thus I have 3 questions:

  1. I found a battery store locally (first one I've ever seen) and they claim they can make a new CMOS battery for that will be compatible. How likely is that? IBM's manual says using any part but theirs may cause an explosion.

  1. I found a store online that claims to sell a compatible battery. Another (Index Computer... that name sounds familiar in a bad way) claims to have the original, but doesn't say it's new. Anybody know of a reliable online store for these batteries?

  2. I am aware that Lithium batteries will explode if (A) they are shorted, or (B) they are charged. But would putting in a slightly incompatible battery cause this? For instance suppose they get the voltage wrong at the local store?

Thanks for any help.

Reply to
ziliath
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Yes, that is right. the battery is acutally just a "coin" type 2032 battery. It is safe to use.

Reply to
news.new

You don't have to buy it from IBM. Any sufficiently compact NiCd battery of the right voltage will do.

IBM's manual is trying to alarm you. IBM does not even manufacture the original themselves, probably. Any electrically equivalent battery will work just as well and just as safely. Explosions (bursting batteries) would result from connecting it the other way around or possibly using the wrong voltage or something else that is wildly off.

batteriesplus.com

By "explode" they mean the battery itself would get hot and slowly burst its seams. (Don't imagine mushroom clouds or windows blowing out!) If the store connects it backward, they'll probably damage your motherboard electrically, which is a more serious concern. But they're unlikely to do that. If we tried to avoid every possible hazard we'd never repair

*anything*!
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Michael Covington
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Reply to
Michael A. Covington

In what I wrote, I was assuming it's a NiCd battery. If it's a lithium "coin cell" then everything is even easier... the battery store should have no problem at all.

(Not, however, the watch section of the local Wal-Mart. I caught them using metal tweezers to hold the coin cells... short-circuiting the cell through the metal tweezers... and wondering why many of the cells were dead by the time they got them in the watch!)

of

would

its

Reply to
Michael A. Covington

I stopped by my local battery store, which turned out to be Batteries Plus itself, and they manufactured a new CMOS battery on the spot using my original's cable. They had a little welder machine there so they didn't even solder it. The new battery so far is working great. Thanks.

Reply to
ziliath

I paid $10 at the local computer shop because I was in a rush. You can get CR2032 from Digikey for $0.53 ea. P189-ND

I did nor want to lose my setting so I changed the battery with the computer running. Double sided foam tape on the end of a felt marker held batteries during the transplant.

--

    Boris Mohar
Reply to
Boris Mohar

What's the product type and model of your Thinkpad? What is it - R31, T30, T20, etc.?

Henry

Reply to
hemyd

Your advice is incomplete and potentially dangerous.

You are correct that a replacement battery need not come from IBM, and that it can be fabricated from generic parts.

However, some laptops use rechargeable batteries (based on any of 3 very different chemistries), while some others use non-rechargeable lithium batteries in a "long life" (3 to 10 years) configuration.

If you try to recharge a non-rechargeable lithium battery, it can indeed explode with enough force to cause injury or death to the user. Lithium batteries are not to be taken lightly, they have killed people and caused the loss of limbs.

So, while the gist of your post is correct, it is absolutely critical that, before trying to fabricate a non-IBM solution, the user finds out exactly what kind of battery they are dealing with, and that the solution be compatible with the existing battery and the laptop CMOS battery circuit.

[Note, attempting to solder to a lithium battery is another way to cause them to explode violently.]

Michael A. Cov>

Reply to
Barry Watzman

I was told by the guy at Batteries Plus that you have to spot weld the wires to the battery because soldering gets the battery too hot. My Thinkpad 560x didn't have a battery holder included.

Reply to
ziliath

Screw that... Just install a battery holder for the darn thing so you can swap it easily next time it dies.

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Don Bruder - dakidd@sonic.net - New Email policy in effect as of Feb. 21, 2004.
Short form: I'm trashing EVERY E-mail that doesn't contain a password in the
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Reply to
Don Bruder

Well, for once the guy was right and not giving you a line. A CR2032 is a lithium battery, and trying to solder to them can result in a surprisingly violent explosion. It won't, always, but it definitel can; lithium is a metal, but melts at a temperature of 180 degress C (about

390 F). Basically, if you melt the lithium, you get the explosion. A soldering iron tip is about 550 to 800 F, but you won't get a battery being soldered anywhere near that hot on it's inside. On the other hand, however, you can't melt solder unless you get the solder and the outer case of the battery up to about 190 C (the exact temp depends on the alloy composition of the solder). So the possibility of an explosion is very real. The devices that weld tabs do so without heating anything but a spot on the surface of the battery past the necessary temperature.

ziliath wrote:

Reply to
Barry Watzman

That's good advice IF there is room, but inside a laptop, there often isn't.

D> >

Reply to
Barry Watzman

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