Quote from: SteveF

Quote from: knightyohhhh... it appears charging and totaly discharging it might have sorted the problem....

Yes - there is almost no chance that a modern battery is being overcharged.  In fact for various reasons to do with the chemical potential in the battery and the voltage supplied by the charger you cannot overcharge them without irreversibly destroying them on the first charge.

In fact the more I think about it the very idea of overcharging is simplty flawed.  Most laptops these days use lithium ion batteries (any laptop youre likely to have will do tbh) and they take standard constant current-voltage charging.  If they didnt lock the chargers voltage accurately (i.e. actually let it overcharge) then you would literally destroy the battery on the first charge.  If you didnt blow it up first try then youre not overcharging.

If there was a mistake in charging it would be an undercharging which basically gimps the capacity of the battery between charges but theyre playing it safe.  Some IBM thinkpads used to do this iirc and then IBM went over the top with checks to make sure it didnt happen again which is probably what Sweensters laptop was going on about.


What Knighty is describing is deep-cycling a laptop battery where you run it flat and then charge it back up.  This again will not destroy it but will substantially shorten its life cycle.  Its far far more likely this is what youre doing to frig your laptop batteries than overcharging.

Except overcharging is a known issue with batteries.

Edit: Just to clarify.

Overcharging = charging the battery beyond its specifications. Overcharging causes heat build up. In Li-Ion this can lead to explosions or simply destroy the ability of the battery to store a charge. In liquid and Gell electrolyte batteries (SLAs for example) overcharging for long periods causes venting to occur as your electrolyte is literally being boiled off due to the heat. This yet again affects your batteries ability to store charge.

In car batteries you can sometimes see the effects of overcharging when viewing the sedement at the bottom of the battery casing. Overcharging and therefore overheating causes the plates to shed their material also.

Once again... this affects the batteries ability to hold a charge.

Overcharging is a known issue. Now granted many chargers today may have smart electronics in order to care correctly for your batteries, but many older laptops (the things people buy as a student perhaps). Do not.

Thinkpads T22 (think thats the name), Packard Bell IGO series, and Toshiba Portege (older models) are ones Ive seen with the particular problem where running on the mains constantly damages the battery so it is unable to accept a charge. There may be a way to recondition the battery using different equipment but it will no longer charge using the laptop.

Personally Id rather remove the battery than take the chance.

Oh and my laptop... I used it as a server at home, it was on 24/7 for about 6 months, when I decided to take it into uni to do some work, it was then that I found out the battery life was harmed it was down to about 30minutes from 2.5hrs, after another week or so of taking it to uni, then taking it home and leaving it a few days acting as a server again... it was down to not even turning on when left charging for hours.

I understand what overcharging is but its a feature of older NiCad and lead batteries and not modern Li-Ions in laptops.  Yes you can overcharge a car battery and its not good for it but that is not a li-ion battery in any sense whatsoever.

You said the dead batteries were due to overcharging which is incorrect.

If you were overcharging them they would destroy themselves when you first charged them with the possibility of them catching fire/exploding being quite high.  After that first charge they would have essentially zero charge and not even power up.

Every battery charger since the dawn of time has had a voltage regulator chip in them to stop overcharging.  You keep referring to fancy electronics to stop this but its just a simple 3 pin chip which costs a couple of pence to buy.  They all have them.

Laptops with Li-Ion batteries are designed to run constantly charging and not being run from the battery then charged.

Peoples laptop batteries die because either they knoc the battery too hard and the plates inside the battery move and short out.  They run them flat and then charge them (deep-cycling) or simply because the power management of the laptop is utter crap and it keep switching back and forwards between the battery and the power supply while plugged in destroying the chemical cell <-- only know a couple of IBM laptops that ever had this latter problem.

Anyway not sure it matters just wanted to explain that overcharging wasnt what was happening but whatever works for you I guess