Full charge capacity vs. Number of charge cycles.

[Humpa]

It bothers me that ibm has seemingly conflicting information on battery health/conditioning related to the Li-ion.
IBM has these 3 documents, the first 2 are in contradiction to any reliable sources I've read on Li-ion health, and only the third is correct:
1. http://www-307.ibm.com/pc/support/site. ... MIGR-50944

Extending battery life - ThinkPad A Series, G Series, R Series, T Series, X Series
Extending the battery life
The Lithium Ion battery pack for the these systems is an intelligent battery. It contains a microprocessor to monitor its capacity. Information of remaining battery capacity is passed to the system from the battery pack, and the system indicates the capacity in 1% steps from 0% to 100% with high accuracy. If the indicator appears to be incorrect, it is recommended that you cycle the battery (fully charge, then fully discharge) three times. This may occur when the battery is over charged or discharged.

2. And, if you click on the Battery Tips link on the Battery Health screen (click on Battery Information > Battery Health), you will see this:

Reconditioning The Battery
Reconditioning your battery can increase the full charge capacity of your battery. It is recommended that you let the battery run to less than 3% at least once a month.

Occasionally, it may be necessary to "deep cycle" your battery one to three times to give it optimum performance. This will require you to let your battery run completely down, and then to recharge it fully. It is recommended that you charge your ThinkPad overnight for a full charge from a deep recharge condition without leaving your ThinkPad powered on. A brand new battery should be fully charged overnight before its first use.

3. But, they also have this (which is the correct info, from what I've read).
This is the one place where ibm got it right. IBM specifically says: Do not deep-discharge Lithium Ion batteries
http://www-1.ibm.com/support/docview.ws ... us&lang=en

Getting the most out of your battery - ThinkPad General
Note:
Do not deep-discharge Lithium Ion batteries. Batteries can degrade when they are left unused for long periods of time. For some rechargeable batteries (particularly Lithium Ion batteries), leaving a battery unused in a discharged state could increase the risk of a battery short circuit, which could shorten the life of the battery and can also pose a safety hazard. Do not let rechargeable Lithium-Ion batteries completely discharge or store these batteries in a discharged state.

batteryuniversity has this page: http://www.batteryuniversity.com/parttwo-34.htm
.. which is summed up at the end, by this:

Simple Guidelines

* Avoid frequent full discharges because this puts additional strain on the battery. Several partial discharges with frequent recharges are better for lithium-ion than one deep one. Recharging a partially charged lithium-ion does not cause harm because there is no memory. (In this respect, lithium-ion differs from nickel-based batteries.)
Short battery life in a laptop is mainly caused by heat rather than charge/discharge patterns.
* Although memory-free, apply a deliberate full discharge once every 30 charges to calibrate batteries with fuel gauge. Running down the battery in the equipment does this. If ignored, the fuel gauge will become increasingly less accurate. The battery life will not be affected.
* Keep the lithium-ion battery cool. Avoid a hot car. For prolonged storage, keep the battery at a 40% charge level.
* Consider removing the battery from a laptop when running on fixed power. (Some laptop manufacturers are concerned about dust and moisture accumulating inside the battery casing.)
* Avoid purchasing spare lithium-ion batteries for later use. Observe manufacturing date. Do not buy old stock, even if sold at clearance prices.

Has anyone asked ibm about this?
It seems clear that Li-ion battery health is adversly affected by deep-discharges. If you try it, you will see (just check your full-charge capacity before and after).

[askew]

Model of thinkpad: T40p
Number of cells: 9
Design capacity: 71.28
Full charge capacity: 68.36
Number of charge cycles: 12
Manufactured Date: 2003-10-21
First Use Date: 2004-02
Number of months since the manufactured date: 10

[rhema83]

Model: T42
Number of cells: 6
Design capacity: 47.52
Full charge capacity: 44.67
Number of charge cycles: 12
Manufacture date: 2004-06-21
First use date: 2004-07
Number of months since the manufacture date: 2

[rgrosz]

Model of thinkpad T41
Number of cells 6
Design capacity 47.52
Full charge capacity 47.50
Number of charge cycles 8
Manufactured date. 2004-04-05 (SANYO)
First Use Date 2004-04

[jsmit86]

Model of thinkpad T42 2378DUU
Number of cells 6
Design capacity 47.52
Full charge capacity 48.16
Number of charge cycles 8
Manufactured date. 2004-04-06 (SONY)
First Use Date 2004-04

[elmokiddo]

T42 2379 DXU

Cells: 6
Design Capacity: 47.52
Full Charge: 49.14
Cycles: 9
Manufactured: 2004-06-15 Sanyo
First Used: 2004-07

Cells: 9
Design Capacity: 71.28
Full Charge: 73.09
Cycles: 1
Manufactured: 2004-05-31 Sanyo
First Used: 2004-07

Elmo

[Daniel]

T42P 2373-KTU

Cells: 6
Design Capacity: 47.52
Full Charge: 41.70
Cycles: 9
Manufactured: 2004-06-14 Sanyo
First Used: 2004-07

I left the 9 cell somewhere else but I rarely use that one. It's only for long trips. Got the 6 cell of EBay for $30 so I don't feel bad abusing it.

All you guys with the high full charge capacity and a decent amount of cycles must've never drained your battery completely. Sorry to say but the full charge capacity reported is inaccurate. Discharge it once to around 3% and you'll know the real capacity. I've gone through 2 6 cells already and I had that high full charge capacity up until the time I discharged it. My 9 cell still has the higher than design capacity full charge capacity.

Sometimes the battery maximizer is inaccurate. I believe that the reconditioning lets the battery circuitry recalibrate itself for accuracy. I've had my Thinkpad shut off completely in 1 minute with 5% capacity which I assume was due to the circuitry not being accurate.

[t41user]

When you ask, "Has anyone asked ibm about this?" - I'd say the answer is sadly laughable, especially if you tape record your phone calls and call IBM repeatedly, hanging up and calling right back to ask another IBM person the same question. In many, many cases you will get radically different answers, with some answers agreeing with one of the IBM documents that you cite and some answers agreeing with another one of the IBM documents that you cite. It's especially sadly laughable when some of the IBM people tell you to ignore certain IBM documents and other IBM people. The sad laughability is magnified when different IBM people give you directly conflicting advice, directly telling you to ignore the other IBM people.

[RS_003]

After reading this, I think the best thing to do is to fully load and then drain it to 3 percent the first time? ( I ask this because ill get my T41P with a 6 cell batt this month )

I will use it for my education, thus I want it to have maximal battery life, because we don’t have any power sockets in the classroom

[vijeshmehta]

So what should new TP owners do to increase battery life? I'm hearing different things, but no solid solution.

1) Drain to 3% the first time?
2) Not to drain less than 40% ?
3) Don't cycle the battery ?

[Leon]

According to Battery University, do the following:

1. NEVER drain or cycle ON PURPOSE, not the first time, not anytime.

2. If you store a battery, store it at 40% charge.

3. An addendum (from Leon University):

Use/enjoy your Thinkpad as much/as many times as you like. If its not convenient to plug in, go ahead and discharge all the way down every day. Whether or not that's good for the battery, who cares! Batterys are replaceable. Good use and enjoyment of our Thinkpads is not.

Isn't that why we all bought a Thinkpads in the first place? If we want to be paranoid about plugging in all the time, we should all get a desktop!

[M4A]

2647-84u
6 cells
38.88 Wh design capacity (@ 10.8V)
32.00 Wh full charge capacity
9 Cycle count
Manufacture date: 2000-12-01 (Sanyo)
First use date: 2001-01 (whole lotta months)

Power use: 8 to 15 watts

[eriqesque]

So far my X40 handles the battery mcuh much better
than my T40 ever did.

X40 2371-8LU
Full Charge Capcity: 62.77Wh
Design Capcity: 61.92
Manufacturer: Sanyo
Cycle Count: 10
Manufature Date: 06-18-2004
First Used Date 08-2004

[cakos]

Model of thinkpad: T42p (2373HTg)
Number of cells: 9
Design capacity: 71.28
Full charge capacity: 72.67
Number of charge cycles: 8
Manufacture Date: 2004-08-06 Sanyo
First use date: 2004-08

Still don't know if it is good or not....

[cliff320]

Model of thinkpad: T23
Number of cells: 6
Design capacity: 43.20
Full charge capacity: 17.78 (!!!!!!)
Number of charge cycles: 95
Manufacture Date: 2003-03-06 Sanyo
First use date: 2003-06


I don't recall ever being hard on this battery, although it's almost always stayed plugged into the wall. There was not a noticable decrease in battery life until I had this computer for about a year and a half, and now I'm lucky if I can get an hour (a lot of it has to do with the PCMCIA wireless card). Just this winter I could chug along for two. Anyway, I figure that at this point, it wouldn't hurt to try the reconditioning-discharge thing. I figure it can't hurt as the battery is basically shot anyway, I'll let you guys know the results. FYI, this thinkpad stays on 24/7 so that may have something to do with it.

P.S. not only does my Full Charge Capacity readout have an asterik by it, but it has two! (My battery health is red, and it is recommended that I recondition it)

===================================
EDIT: Results of my reconditioning

Starting full charge capacity: 17.78 Wh
After one discharge cycle: 27.55 Wh
After two discharge cycles: 31.47 Wh

I figure a third discharge would an even smaller effect if any at all, so I stopped with two. All in all, not a bad result, I went from >1 of battery life to a little more than two.

[ranjit]

Here is mine...

Model of thinkpad: T42 (exactly four weeks old)
Number of cells: 6
Design capacity: 47.52Wh
Full charge capacity: 47.55Wh
Remaining capacity: 47.55Wh
Number of charge cycles: 32
Manufacturer name: Sanyo
Manufacture date: 2004-11-15
First used date: 2004-12
Number of months since the manufactured date: 3

I have been turning off and booting up the T42 everyday thereby increasing the number of charge cyscles (currently at 32). I gather that this is not good practice and it is best to either leave the T42 on 'standby' or 'hibernate'. Please advice.

Cheers and best regards,
Ranjit

[Sasha]

Model of Thinkpad: T42p
Number of Cells: 9
Design Capacity: 71.28 Wh
full Charge Capacity: 68.05Wh
Remaining Capacity: 68.05Wh
Manufacturer Name: SANYO
Manufacture Date: 2004-12-07
First Used DatE: 2004-12
number of Months Since the Manufactured Date: 2
Number of Cycles: 34

[t41user]

Does anyone here deny that current and past IBM documents instruct users at regular intervals to deep discharge - all the way to down to 0% so that your system automatically shuts down? I can find numerous IBM documents for the 6 and 9 cell T4x series batteries that instruct users fully to deep discharge their batteries. There is no ambiguity in wording. These current IBM documents are telling users what to do periodically with their Li-Ion 6 and 9 cell batteries for T4x thinkpads. Does anyone here deny that current IBM documents and programs say such things?

If you ask IBM about this they will tell you that Li-Ion batteries do have a memory effect. If you try to disagree with them, IBM will tell you that in order for the battery and the thinkpad accurately to indicate the condition of the battery and the actual current charge, you need fully to deep discharge Li-Ion batteries down to 0% at regular/periodic intervals.

[Paul Unger]

T42 2373-3UU

Number of cells: 6
Design capacity: 47.52
Full charge capacity: 36.72
First used date: 2004-07
Number of cycles: 44

What's the procedure for getting a replacement? I think I'd qualify . . .

[Leon]

they won't send you one unless your battery condition is "red"

[t41user]

I might be misunderstanding you Leon, but is that right? Might not IBM replace a battery under warranty if the condition is not red but the battery consistently fails to perform adequately? For instance, if a battery always gives apparently inaccurate capacity readings and also always only lasts, say, 5 minutes or 45 minutes, might IBM still replace the battery even if it does not read condition red?

[Leon]

they may, and although there has been conflicting information on this board, I know of cases when the returned battery WAS tested....

[edelrc]

Discharging? Lests see, today I wnated to measured the "gain" in Reconditioning my battery with IBM´s tool

This morning:
Number of cells: 9
Design capacity: 71.28 Wh
Full charge capacity: 67.42 Wh
Number of charge cycles: 05
Manufactured Date: 2004-05-19
First Use Date: 2004-07

After Reconditioning:
Number of cells: 9
Design capacity: 71.28 Wh
Full charge capacity: 64.44 Wh
Number of charge cycles: 07
Manufactured Date: 2004-05-19
First Use Date: 2004-07

Not only I lost almost 5% of capacity but also i´d got 20% more cycles. GREAT

Screw what IBM says... That is the last time I do the reconditioning!!! (And sure I lost the other 3 Wh when I reconditioned it two months ago!)

[CrazyJeeper]

Model of thinkpad: T42 (2379-DXU)
Number of cells: 6
Design capacity: 47.52
Full charge capacity: 42.55
Number of charge cycles: 10
Manufature date: 2004-10-21
First used date: 2005-01
Battery Brand: Sony

I have already done a battery recondition cycle on it becuase for a week straight it wouldn't go above 97% when I had it pluged in for days. It appears that doing the battery recondition I have lost some battery capacity. My T42 spends about 80% of the time plugged in. This is my main computer since I don't have the room for a desktop in my matchbox apartment room.

[edelrc]

That it does not go beyond 97% should not be because of need to be reconditioned. Left-click in the percentage of battery charge and then select Improve battery Health. There may be your answer.

Also, some have said that discharges may be good, but don´t go lower than 5%. Well, when you recondition, power goes to 0%. So, I guess, we should forget about this tool altogether.

[daeojkim]

Model of thinkpad: T42
Number of cells: 6
Design capacity: 47.52Wh
Full charge capacity: 48.16Wh
Number of charge cycles: 11
Number of months since the manufactured date: 2004-09-16

[steveho]

Model of thinkpad: T30
Number of cells: 6
Design capacity: 47.52Wh
Full charge capacity: 4.25Wh
Number of charge cycles: 661
First Use date: 2002-10
Sanyo

[IR0NMAN]

Model of Thinkpad: T42 GVU
Number of Cells: 9
Design Capacity: 71.28Wh
Full charge capacit: 73.13Wh
Number of charge cycles: 11
First Use date: 2005-01
Manufacturer Date: 2004-12
Sanyo

[edelrc]

I see, I see.
So now those with 9cell has more cycle counts (average 11) than me (9), yet I have around 10% less Full charge capacity...

Could it be because of the 2 "IBM suggested" Recondition battery tool I did???
(I have only once actually unplugged the laptop) That is not fair!!!!

[Marc_G]

Quick not to those who tried to use the reconditioning tool to get back their capacity, in cases where the battery wasn't that bad off to begin with (>~75% of design capacity):

Don't do it!! The reconditioning cycle is meant to restore seriously depleted batteries. So, if the design capacity is 72 WH and you're reading 65 or whatever, that ain't bad. When you get down to 40 or so, then do a reconditioning cycle and you'll probably see a decent gain. It's worked for me, time and again.

Small incremental losses are inevitable with this battery technology, so don't sweat a WH here or there.

Marc