Thinkpads Forum

Steerpike wrote:where do I see 'wear %' ?

wear = Full Charge Capacity / Design Capacity

My understanding is that batteries start to deteriorate on the date they are manufactured, correct me if I'm wrong.

According to the power manager, it shows the manufacture date along with the first used date. Does anyone know if the power manager calculates the "design capacity" based on the manufacturing date or first used date?

In fact, as noted these batteries have considerably accelerated deterioration when fully charged. Therefore I prefer not the charge them fully. In fact, most of the time I use the adapter and don't even have the battery installed. If I need to use the battery, I will charge it.

Even if I have the power options set to keep the battery charge level below a certain threshhold, the heat from the unit will transfer to the battery by convection and that too amplifies deterioration. I'm not concerned particularly about the danger of data loss should the adapter plug come loose.

The battery will last longest if at around 1/2 charge, 40% actually being best, and refrigerated. However, I haven't bothered to keep mine refrigerated. My house has been cold enough since I got it late November. Maybe in the warmer weather I will refrigerate it.

This may be a noob question as well, but is there any way to set those thresholds under Vista? I looked under the Vista power management program, but there's no such option... I successfully installed Battery Maximiser 1.38, but I don't see any option for setting charge thresholds even under the "customize" option.

nivlam wrote:My understanding is that batteries start to deteriorate on the date they are manufactured, correct me if I'm wrong.

That is right.

nivlam wrote:According to the power manager, it shows the manufacture date along with the first used date. Does anyone know if the power manager calculates the "design capacity" based on the manufacturing date or first used date?

I don't think that is the case. Because then, they would have to assume a steady deterioration rate. That is not logical, since we know that the deterioration rate changes according to usage.

Actually, calculating the design capacity shouldn't be that hard. After the production of the battery, charge it until it's full. Attach it to any device that consumes power at a steady rate (e.g. a resistor), and measure the power consumed until the voltage drops below the level that is required to run the TP. That will give you the design capacity, i.e., the full charge capacity right after production. Also, I guess the batteries have a little chip (eprom) on them that they record the manufacturing date, this desing capacity, and serial number etc. Basically, all the information on the right hand side column in Power Manager's battery information window. This, kind of gives a clue that they are stored on a chip and static, i.e., do not change like the other information on the left hand side column.

To me, calculating the "full charge capacity", on the other hand, is a mystery. Mac laptops (as all other laptops) report an estimated time for the remaining charge in the battery. In their user manual it says that, over the time, this estimation may lose accuracy, and it may need to be recalibrated. The calibration procedure is: charging the battery until it's full, and then discharging it until the laptop shuts itself down. During this discharge time, the OS records used energy (Wh) and this becomes the new "full charge capacity" of the battery. According to this new value, the remaining battery time can be estimated more accurately.

Probably Thinkpads do the same thing as well. But I, for instance, have never fully discharged my battery. So I don't understand how it can give me this number with a high 0.01 Wh accuracy. Maybe it employs an algorithm according to other information about usage and stuff and come up with a number. But still, I can't really see how it can report a realistic full charge capacity without measuring a full discharge cycle.

best to let worn out batterys drain completely @0%,till the machine powers off,(all new hdds have safety buit into them not to damage the heads).then let cool off ,refiit then recharge them to 100%in windows only,then imedietaly remove and let cool of before reffitting them permanently on the machine not any less than 100%(period),and do not use any ibm 3rd party maximiser programs or battery tools unless you are certain your battery will communicate as ought to to the software(but i doubt it)or is within warranty replacment period,you see the methods suggested by ibm are desighned to screw the batterys instead of prolonging the lifespan of lelion cells
which i have proved can run reliably even after 8 years from the packaged battery date on various branded machines.
for christs sake be fooled no more ,there is no such thing as discharge cycle life unless the manufactures implement rort orientated electro commands to deliberately shorten the life span
get it!
for example a 3yol tp battery shows 25 minutes charge
with ibm recommendations lappy suspends approx 3% of charge
then powers off till you charge again ,now this only gave me 25minutes,now we do gods way
piss off the ibm maximiser crap,reboot set the low batt warning on all accounts to 0%,its tricky but you slide the bar and hold an coccurently press enter at the same time to force the magic 0%
(nice try microsoft,betya reaped heaps in royalties from ibm)
uncheck all the suspend hibernate settings,all in order to let the battery run its natural course.
reboot run on battery and guess what,2hrs +51minutes from a 3 year old battery running max cpu speeds
despite all software implicating the battery lost 87.5% charge,
why because its all lies ,lies lies.(smart battery? definetaly for revenue)too bad no one pursues arbitratrion to put and end to the myths
so i will sell the new battery the fooled ibm customer purchased from the laptop deal i done,as a token pinch the sale from ibm,thus ensure global warming is kept to the minimum and use the 3 yold battery for many many years without the gimiicks.
one important factor is make sure the battery remains cool
do not discharge and recharge immedietaly unless one must do so.
hope this helps some.
update/the 3 year old battery now shows 35% wear and runs over
8.15hrs idle in windows screen and hdd powered off
same trick works on 600sereis however t21 batterys have stubborn memory eeproms,despite claiming 91% wear
i get over 2.5hrs on wifi/max speeds by means of
not using ibms usless battery software and powermanagment drivers.this is from 3 different 6 year old t2xbatterys!
as you see its a rort because ibm does not provide proper slow discharging recalibration software that provides resett for their eeproms,if anything their fast discharge methods via battery maximiser will indefinetaly contribute to shortening the life span
via eeprom manipulative measures.
this is the modern day rippoff techniques them greedy schemers
use to culminate in profits,the hp 4150 sereis are proof that
batterys can be designed in a proper manner addressing long life
thus reducing he effects of global warming.8 years not one single battery failure and true for the end user battery eeprom calibration,
regardless of working enviroments and full discharges.