Tech: OT--Laptop Battery

Subject: Tech: OT--Laptop Battery
From: GUEST,saulgoldie
Date: 23 May 06 - 08:51 AM

Due to its having sat unused for too long, my laptop battery has gone "foof." Since it is an older unit, the replacement battery costs more than half of what I could buy a whole new (used) replacement computer, and then it gets into the economics of getting a more current unit with newer OS and gizmos. I am not prone to tossing out useable machinery, and I would like to keep using this one if I can do so at reasonable expense.

I think I remember that batteries can be revived, but I forget the process. Does anyone know if it can be done, and if so, how? Thanks!

Subject: RE: Tech: OT--Laptop Battery
From: MMario
Date: 23 May 06 - 08:54 AM

if it will charge at all; charge, discharge completly; charge, dishcarge completly; etc. usually get a longer life each time until back to nearly normal.

If it won't charge at all - doubt if you can recover it.

Subject: RE: Tech: OT--Laptop Battery
From: Stilly River Sage
Date: 23 May 06 - 12:03 PM

I had a bettery that didn't work at all but I had to leave it in the laptop. For some reason, I don't know if it was unique to Acer, if the battery (even a dead one) wasn't in place I couldn't get the computer to work with the AC connected either.

SRS

Subject: RE: Tech: OT--Laptop Battery
From: M.Ted
Date: 23 May 06 - 02:33 PM

MMario's advice is about right, but, just to cover your bases, go to the website for the battery mfg--they will have info on the care and feeding process--one thing to remember about the new "used" computer is that the battery will likely not be new (even when they say it is)and you may have the same problem again soon--

Subject: RE: Tech: OT--Laptop Battery
From: Stilly River Sage
Date: 23 May 06 - 03:16 PM

Proof read or learn to type, that is my goal!

If you go to buy a new battery, be careful buying batteries online if you're looking for the savings of a no-name type. There are some that have been known to be so inferior that they explode or catch fire (I think the instance I read about was cell phones, but it can happen with any kind of battery).

SRS

Subject: RE: Tech: OT--Laptop Battery
From: JohnInKansas
Date: 23 May 06 - 03:34 PM

If the computer will run on AC (usually through an adapter) with the battery installed it's possible it is charging but a fully discharged battery takes a very long time to come back to useful charge. If you haven't left it on for at least 24 hours it may just have not had time to come back to life. Even at 24 hours charging may not be complete if you started with a fully discharged battery, but should be up enough to tell that it's getting some charge.

If you have the common Lithium Ion or Lithium Polymer battery, the normal charging cycle is a constant charging current until the battery comes up to normal voltage, but then the charging current is reduced to 10% (or less) of the intital current value to complete charging. Full cell voltage is reached at less then 40% of full charge, so when the input current drops it takes a long time to actually "fill it up."

If, with this kind of battery, something turns on when you try to start the computer with battery-only power, but it just dies almost immediately, leaving it on the charger for longer may finish the charging. Depending on the charging system built into your computer it could take several days.

With Lithium batteries the voltage does not increase after the battery is up to the "format voltage," and the slight resistance change that happens when the battery is "full" is too small (and inconsistent) to be used to control charging. (i.e. there is NO practical way to tell when the battery is fully charged.) Overcharging will destroy the battery, so most "chargers" built into laptops use a very low "finishing current" and a timing circuit to guess when to cut off the charging, hence getting past the half-way-charged point may be a very slow process.

Your battery should be labelled to show what type it is since in most places it's a cert requirement so that proper "toxic disposal" can be done. If it does not indicate "Li" or "Lithium" then you have one of the other kinds, with different rules to be used.

John

Subject: RE: Tech: OT--Laptop Battery
From: JohnInKansas
Date: 23 May 06 - 03:55 PM

Stilly - 23 May 06 - 03:16 PM

Battery recalls have been seen for laptop makers using the Lithium batteries. Apple has had at least three and HP at least two, that I've seen. I suspect others that just didn't get noted.

So far as reported, all recalls have been the result of incidents involving "smoke and flames" but no real explanations have been available, and beyond the rather bland "we'd like to replace your battery" (or your computer) the manufacturers involved have "minimized publicity."

I've had engineering applications requiring me to request information from the battery manufacturers, and they just "quit talking" when the subject is mentioned. While I know of some battery processing defects that could be responsible, there's a possibility that some of the problems could also be due to poor charging circuit/system designs, but the whole subject is "closed to outsiders" so far as battery makers are concerned - even, in my case, when someone's offering them a significant contract with lots of money for the next thirty years. (Or the ones I talked to could just be idiots who didn't know anything about their own products, which is not really rare recently.)

John

Subject: RE: Tech: OT--Laptop Battery
From: JohnInKansas
Date: 24 May 06 - 03:02 AM

Addend on Lithium batteries (the most common kind used for laptopts).

The discharge "completely and recharge" advice applies to NiCad and some other kinds of batteries, but is NOT a recommended procedure for Lithiums. Discharging below the point where the voltage starts to drop will shorten the life of the battery, and full discharge may make one unrecoverable. Li batteryies are shipped charged, on the assumption that they'll arrive and be placed in use before fully discharged, and laptops in particular will normally turn off once the battery voltage starts to decrease, to prevent complete discharge.

One packager, probably a manufacturer, states that all Li batteries should include several safety features. I'm not sure whether he is referring to "batteries" in the technically correct sense of multi-cell packages, and whether this also applies to single cells (commonly but improperly called "batteries.")

In packaged Li batteries for a computer, to prevent hazards to users, all batteries should have an internal fuze that opens if rated input or output current is exceeded. This permanently disconnects the cells from the output terminals and renders the battery "dead."

In packaged Li batteries for a computer, to limit the hazard from case rupture, the same or a separate fuze will permanently disconnect the cells from the output if the battery temperature exceeds a temperature set by the manufacturer, usually about 100 C.

In some areas, one may find "battery shops" that advertise the ability to rebuild "packaged batteries," including the kind used in computers. They can open up the case, match the type, size, and number of cells with replacement cells, and hence produce "rebuilt" batteries at prices they claim are significantly cheaper than getting manufacturer's replacement batteries. I have no experience with these kind, but some people I've known have said the ones here did a good job on replacements for their portable hand tools.

Most of the batteries people claim to have had rebuilt, though, are "screwed together" cases, so breaking out a seal over the screws allows easy disassembly. Most computer batteries I've seen have welded, molded, or glued-together cases, so they would have to actually "break" the case to get into it. Inquiry with a shop of this kind might be worthwhile, but a liberal dose of "good judgement" should be applied to their claims before handing over your cash.

John

Subject: RE: Tech: OT--Laptop Battery
From: The Fooles Troupe
Date: 24 May 06 - 10:50 AM

I had a friend who bought a new laptop within the last year, and the battery died within a few weeks - it was replaced under warranty.

Subject: RE: Tech: OT--Laptop Battery
From: EBarnacle
Date: 24 May 06 - 10:57 AM

We got a laptop at a rummage sale. The sign said battery NG. We tried charging it in the computer. Nogo. I removed the battery and charged it outside the computer. All of a sudden, everything works well. Life cycle is that the battery has not run down in use since charging. It is now really a portable computer. Unit is a gateway 2000.