Laptop battery doesn't hold a charge anymore....

[Gooberlx2]

So my laptop doesn't hold a charge anymore. Unplugged it'll last only like 15 mins where it should last atleast 2.5 hours. I kinda figured it was just because the wireless card was sucking so much juice, but I unplugged that and it still only lasted about 15 mins.

Now perhaps, it's the use of the pcmcia at all? (I still had a usb2 card plugged in for my external HDD). But that just seems odd, and really crappy if that's the case. The pcmcia wireless card is a Microsoft 802.11b card and the usb2 card is a generic one.

Hopefully it's just the battery and not the use of the pcmcia at all. Any ideas?

Dell Inspiron 4100
Microsoft 802.11b wireless pcmcia
Generic USB2 pcmcia


Anyway, what causes a battery to not hold a charge anymore? Most of the time I leave it plugged in because I just use it at a desk. Is this bad?

 

[dkozloski]

I am still using the original battery that came with my Sony Vaio in 1997 and according to the battery software it still has 96% of original capacity when fully charged. I pretty much did anything I wanted with it from keeping it fully charged to laying around stone dead to plugged in continuously. Go figure.

 

[TechnoPro]

I've read recently that leaving the battery in while running on AC current can seriously degrade battery life. Despite that warning, I still keep my battery in, even when using AC power.

 

[dkozloski]

I think a lot depends on how much care the manufacturer took in designing the battery charging and maintenance system in the laptop. Some do a better job than others. This would explain the widely varying experiences of users.

 

[DemiSheep]

I am no expert on laptop batteries. but I believe no one knows (talking about general pc users) how to take care of their laptop battery. I always go with this: Exercise the battery. If its fully charged unplug the power cord and let the battery run down. Then plug it back in. Most rechargable batterys have to be done this way or they go bad fast. I dont know if the newer types of batterys are like this or not....

 

[MercenaryForHire]

Originally posted by: Gooberlx2
Most of the time I leave it plugged in because I just use it at a desk. Is this bad?

Yes. That kills batteries.

Check your manual - I don't know the recalibration process offhand, but basically you need to do a few good deep cycles. A factory recalibration just does it quicker and automatically.

- M4H

 

[Blastman]

Yup, it looks like those lithium-ion laptop batteries are like Nicd rechargeables. They have built in overcharge protection (chemistry) but eventually lose it from continually overcharging. Apparently Nicd?s can handle about a year of overcharging and then damage quickly after that. I would imagine Li-ion batteries are about that same. Although it probably varies with how much you are overcharging them.

I think they need smarter charging circuits in laptops so they trickle charge at very very low rates = less damage to batteries = much longer life.

I?ve had rechargeable AA Nicd?s for years and they?re still going strong. They?re rated for 1000+ charges (probably if you don?t leave them in a charger all the time).

 

[corkyg]

After all the pontificating, etc., the answer is - time! Laptop batteries, no matter how good or how taken care of, do have a finite life and all will eventually cease to take a charge. The more you use it, the shorter will be the life.

I can speak from experience - am on my 5th laptop. One had poor quality batteries - or at least the batch I had was poor. My current one has been perfect for 2.5 years now - but each deep recycle/calibration (about bi-monthly) comes up a little less than the time before.

BTW - the first three were NiMH - the last two are LiION - definitely better.

 

[sharkeeper]

Very short life indicates that one (or more) cells is way out of equalisation with the others. ALL cells should measure at least 3.00 VDC when fully discharged. Full charge should read 4.2 volts per cell.

Sometimes a pack can be restored by charging the culprit cells with a lab supply set at 4.2 volts. Limit the current to no more than 1/5C to prevent the cell from heating! If you don't understand these terms, DO NOT open the pack! Mishandling Li Ion cells can result in burns, property damage and other issues you probably don't want to deal with!

If you're going to leave the battery stored, it is best to leave them 50% charged and NOT fully charged.

Leaving the charger plugged in all the time is generally OK. If this kills the battery, blame the charger/battery manufacturer not the battery as the design is poor.

Cheers!

 

[Mark R]

Virtually all Li-ion chargers are configured so as not to overcharge lithium batteries. Li-ion batteries can't be trickle charged because it isn't possible to measure accurately the state of charge when trickle charging. Li-ion batteries have a nasty habit of bursting into flames if overcharged, so preventing overcharging is essential. I'd be extremely surprised if any major laptops damaged batteries by leaving the AC supply connected - this is a completely preventable problem, if present, it would indicate extremely poor design.

If the battery can't hold a charge, then it is defective. The most likely problem is a faulty cell within the pack. It may be a manufacturing fault in one of the cells, or the battery may simply have reached the end of its life (250 full charge/disharge cycles is typical for Li-ion - but many more if discharges are shallower), or it could be mechanical damage (from being dropped).

You need to replace the battery, unless you are confident to try and equalise the pack as described above.