Laptop Battery 'Retraining'?

I've always heard that the Lithium Ion Batteries don't have a "memory" so they don't care how often they get run down and recharged but I have found that not to be true. I have an old R40 Thinkpad that has a battery in it that is at least 6 years old and the computer still goes an hour and a half on the battery. I let the battery run dead once a week or so, then give it an 8 hour charge. I've done this since I got the R40 6 years ago. I also have a T60 I bought used that I've had for about a year and a half now and I'm doing the same thing with it. It has the 9 cell battery in it and will go more then 3 hours on the battery. According to the battery info, the T60 battery was first used in January of 2009 so it's 3 years old.

 

I run my laptops plugged in most of the time but at least once a week I just run the batteries down about once a week or so.

 

You can't fix how much charge the lithium battery holds "Train them" but you can calibrate the battery meter,ATM it registers 10% more charge than it actually holds catching you out and it can damage your battery if it carries on further lessing its lifespan.There is no negative 'memory effect' with lithium batteries so it doesn't matter at what percentage you charge them at in general use.

This calibration is actually bad for the battery in the short term so you should only perform it once but it with in the long term its life will be prolonged.

http://batterycare.net/en/guide.html

I've had mixed results with this procedure and variants of it but it always moves closer to the battery's 'actual' charge.

I never run a lithium battery down all the way unless I have no choice,a full discharge should only be done once every couple of months or less,whenever it loses calibration with the windows power meter. I've done my laptop once in two years.

 

I may be wrong but I believe Windows 7 sees the eeprom in the battery and then will not allow a full charge after a certain threshold is met. You can google laptop battery eeprom reset to see what I mean. I have read that some Dells will refuse a recharge after a certain number of charges.

You can see what the last charge on the battery was by entering this at the command line.

powercfg -energy

It will create a log file called energy-report.html in Window\system32.

Scroll down until you see Battery:Battery Information

 

That's a great little tool

 

Hi,

Look at it this way: You are not "retraining" the battery. You are giving the Charger Circuits in the Battery case and the Laptop a chance to find out where Zero and 100% charge lies. Most manuals give a procedure for that. The simplest one I have seen is to put the laptop into Safe Mode and let it run until the battery dies. Another turns off all auto alarms and shutdowns and lets it run until it dies. Hope this clears up some of the confusion.

Good Luck, Jim

 

What i do is if you use the power cord all the time i would take the battery out no point on wasteing a battery if it is not being used.I would only use a battery if your going on vacations or moveing around.

 

Hi Again,

Modern charger circuits are pretty good. They only charge the battery until it gets to 100%. It will not hurt the battery to leave it in while you are running on AC. It also will not hurt anything if you would rather take it. outl.

Jim

 

Two things are particularly hard on all rechargeable batteries, continually recharging a battery that hasn't really been discharged and recharging a battery from a totally discharged state.

Leaving you're computer or any other rechargeable device plugged in all the time can result in the first condition. This can be particularly problematic with NiCad and NiMH cells because of their generally subtle memory effect but a lot of chargers will tend to mildly overcharge lead acid and lithium cells under these conditions as well.

The second obviously occurs when people are either intentionally or unintentionally deep cycling the battery. Deep cycling can restore some capacity to a nearly spent battery but shouldn't be done on a weekly or otherwise regular basis.

I tend to leave my laptop plugged in Monday through Thursday and have it on the road Friday through Sunday. I rarely discharge the battery below about 20-30% and prefer to plug it back in at 30-50%. The same goes for the two dozen NiMH AA, AAA, and C cells I use. No leaving them on the charger for weeks at a time. No discharging them completely on a regular basis. I tend to get longer than the typical life out of them all.

 

Hi Cachehiker,

You are 100% correct but:

1. The automatic charger circuits in a laptop do not continue to charge the battery after it reaches 100%

2. The procedures in the User Manuals for laptops do not completely run down the battery. The charger circuit will shut down the laptop when the battery reaches a certain % of charge. It's not a "Deep Discharge" and again it's to let the charger circuit see where 100% and "0%" are.

Jims

 

Hi LauraR,

Should have mentioned that a batt that is to the point yours is will not be helped by "Retraining/Recalibrating". That's a defective battery.

Jim

 

You can buy longer life batteries for your current laptop if you wish,they're slightly more expensive but may be worth a look,an upgraded battery can in some cases have double the life of the stock battery.

Is the shutdown an instant shutdown or does it go into sleep/hibernate mode just below 10%? If it's an instant shutdown you need to set your low battery alarm and hibernate to a higher setting.

Control panel,power options,change advanced power settings,scroll down to the bottom 'battery' and set your

Critical battery level to 10-12% 'Or just above when it shutsdown '
Critical battery action = sleep
Low battery level = 15% 'Or however much warning you want'

The instant off is bad for the battery as its almost completely drained,letting it go into sleep at a higher level then plug it back in,it should keep the 45mins running for much longer.

 

Most of my chargers (laptop too) will momentarily jump back into charge mode following power interruptions and if I so much as unplug them for a minute or two to rearrange cables and whatnot. The cell voltage is higher while charging, so chargers don't always recognize the pack as still being fully charged right away. The worst case would likely be laptops that are routinely unplugged and plugged back into different outlets.

Battery packs also self-discharge and will trigger the occasional topping off. This can also be a circumstance where a less robust charger doesn't immediately recognize the battery as essentially fully charged.

Laptop battery monitoring and chargers are pretty good nowadays but I wouldn't count on them being perfectly matched to the battery packs they're connected to. I wouldn't be surprised if every few "topping off's" could sometimes end up counting as an actual charge cycle, especially if the battery is old and its calibration has been rendered less than accurate.

A lithium cell holds its charge well though. If a laptop is run on battery power once every week or two, I'd be surprised there's any topping off happening in between the charge cycles.

My comment regarding deep cycling was targeted at those who think this is really the way to extend a battery's life and intentionally run their batteries all the way down. It can help in some circumstances, but often does more harm than good.

I also wouldn't be at all surprised to hear some manufacturers are pushing it with regard to safe discharge levels in order to advertise longer battery life.

 

Hi,

Cachehiker is still right but one small detail was omitted. The variation in battery voltage is how the charger determines the state of charge of the battery.

Jim