So what triggers battery health to go red?

[rgbyhkr]

Ok, I'm just starting to learn about battery health (I know, I should have been doing this from the start). I have had a T42 since last June and have been using the additional 9-cell I bought as part of the original order as my only battery. From the battery information screen, it looks like I've had some pretty good capacity loss. Here are the stats:

Full Charge Capacity: 47.02Wh
Design Capacity: 71.28Wh
Cycle Count: 374
First Used Date: 2004-06

Ok, so it comes out to just over 34% battery loss. Yes, I know the cycle count is incredibly high. I'm still not sure I understand what cycle count is, but my use is obviuosly an example of what not to do. I truly do use it as a portable and very often use it while not plugged in.

I understand the current state of battery tech and my own ignorance regarding how my use has contributed to the capacity loss. To that end, I have purchased an external charger to swap out batteries (with my original 6-cell), will avoid deep cycling as much as possible (will try not to even go below 10%), and am considering the purchase of a third battery to include in the swapping mix.

I'm assuming that the battery health color is based on the ratio of full charge capacity vs design capacity. Since mine still shows green, I haven't reached that point yet. Anyone know what that ratio is?

Thanks.

Jeff

[rgbyhkr]

Well, I guess it doesn't really matter at this point. I called tech support to ask a quaestion about the multiple battery charger and about this issue. I mentioned that my 9-cell had lost capacity, he asked if it was under a year old. It is and when I told him it was, he said they'd just go ahead and rfeplace it. I certainly never expected that. The new one is on it's way. Thanks IBM (or do I say Lenovo now? ).

[redsb3]

A cycle is ANY discharge and recharge, so everytime you use it on battery power and then plug it into AC and recharge the battery, that is 1 cycle. Since your notebook is nearing one year old, you must be doing this almost every day to achieve a cycle count over 300. Anyway, glad to hear you got lucky and had your battery replaced under warranty.

[rgbyhkr]

A cycle is ANY discharge and recharge, so everytime you use it on battery power and then plug it into AC and recharge the battery, that is 1 cycle. Since your notebook is nearing one year old, you must be doing this almost every day to achieve a cycle count over 300. Anyway, glad to hear you got lucky and had your battery replaced under warranty.

Thanks. That was exactly the kind of layman's explanation I was looking for. Yes, I have done this quite a lot, sometimes quite a few times in a given day. I was basically just plugging it up when I could. If I was in one spot and near a power outlet, I plugged it in and unplugged when I needed to move around with it.

[beerak]

A cycle is ANY discharge and recharge, so everytime you use it on battery power and then plug it into AC and recharge the battery, that is 1 cycle. Since your notebook is nearing one year old, you must be doing this almost every day to achieve a cycle count over 300. Anyway, glad to hear you got lucky and had your battery replaced under warranty.

Thanks. That was exactly the kind of layman's explanation I was looking for. Yes, I have done this quite a lot, sometimes quite a few times in a given day. I was basically just plugging it up when I could. If I was in one spot and near a power outlet, I plugged it in and unplugged when I needed to move around with it.

No, I think you're wrong.

A one cycle is defined as a 80% power loss and recharge.

So if you charge from 80 to 100 then you would need to do it 4times to fulfil one cycle.

[admsteiner]

A cycle is ANY discharge and recharge, so everytime you use it on battery power and then plug it into AC and recharge the battery, that is 1 cycle. Since your notebook is nearing one year old, you must be doing this almost every day to achieve a cycle count over 300. Anyway, glad to hear you got lucky and had your battery replaced under warranty.

It's not *any* discharge and charge, its only when the battery drops down or charges above a certain amount (not sure which or how much).

--Adam

[Thinker]

To me, laptop batteries are like women. Such a mystery. Can't live with them, can't live without them, and so forth.

I've never understood chemistry (whereas I was great at Physics), so maybe that's why I don't have the slightest clue as to what determines a battery useful life. Plus, I have seen a lot of contradictory recommendations (all of them for Li-Ion batteries, I'm not getting mixed up with NiCd). I have heard that you need to discharge completely, that you shouldn't discharge below a threshold level, etc.

I think it would be interesting to investigate how batteries behave differently due to climate factors (humidity, temperature), as I am sure this accounts for a lot of the apparent inconsistencies in battery behavior (as the different manufacturing am sure also does).

In sum, can anybody explain laptop batteries to me? Just Li-Ion, don't need to write a book. Is there a proven method to maximize the life of a battery, and can you back up your assertions?

Thanks,

Ruben

[redsb3]

Sorry guys, but I'm right. I researched this extensively three years ago in order to determine how to get the best life out of a Li-On battery. I managed to make them last almost three years and still produce about 60 minutes of useable time. This was more for my own interest than anything else. Perhaps on some notebooks there may be a threshold of 95% or thereabouts, but once you discharge a cell and then recharge it back up, it is a cycle. That is how the microprocesser inside the battery records it, period. Now the software side of your notebook may not "see" it that way, but the battery records a cycle none the less.

rgbyhkr more or less proves my point, his thinkpad is not yet a year old and has recorded 374 cycles, this is more than one per day.

You could experiment with your thinkpad and the battery maximizer program. It records the cycles, so see if it records a cycle if you only discharge down to 90%, 85% etc. I haven't played with mine as I haven't had my T42 but about a month now. Regardless of if it does or not, I can guarantee that the microprocessor inside the battery has recorded a cycle.

You can make batteries last a long time but it is a royal PITA. It involves having two batteries to swap out and storing the ununsed one in the refrigerator at 45 degrees or slightly less, but not freezing. You must remove it once a month, warm it to room temperature and recharge it to full charge, use it down to about 5%, recharge it and use it again down to 40%. It must be stored at 40-45%, not a full charge. The cold reduces the chemical reactions of the lithium, so that the self-discharge is negligiable. I managed to make two batteries last three years and still produce an hour of useable time (only gave 2 when they were brand new)

The biggest destroyer of Li-On batteries is HEAT. Never let your notebook in the car for any length of time, summer or winter. Heat will kill the batteries and the cold is no good for your LCD display. I have advised many people who thought the battery was a good UPS in case the power goes out, to buy a $35 UPS and let the battery out of their notebook. For one thing, the battery self discharges about 1% every day whether you use it or not and the constant charge back to full is not good for it. Second, the inside of a notebook is like an oven, although ThinkPads are better at heat management than most, it is still being subjected to unnecessary heat. A $35 UPS is one heck of a lot cheaper than a $169 battery.

It only takes one cell to die in a modern Li-On and the battery is basically trash. Since the cells are all connected, the good ones will discharge to the dead one, trying to even out the cells. When you have a battery that charges to full, shows 100% and then you put it in the notebook and it lasts about 10-15 minutes, or drops rapidly to show very low percentage, this is mostly like what you have, a dead cell.

There are a lot of myths out there about Li-Ons but if you want to get the most out of your battery, use it down to 5% or so before recharging. I know, your going to say that its bad to deep cycle a Li-On. Partially true.
The cut off voltage in a Li-On cell is 2.4V. Below that point, irrepairable damage is done to the cell. It will probably never recover and will never be able to accept a charge. Therefore, the microprocessor inside the battery will shut your notebook down well before that happens. Ergo, no damage to the cell will occur because the microprocessor will communicate with the notebook and if you don't shut it down, it will turn itself off to prevent damage to the cells. This will occur at about 2.7V, a generous safety margin. So how can you really damage a battery by deep cycling it if it turns itself off before any damage can occur? The answer is simple. The longer the battery has to be charged, the more heat is generated and what is the biggest enemy of Li-On batteries, exactly. However, in the real world, this will get you the most out of your batteries. A Li-On can only be recharged X number of times ( the generally accepted number is between 400-600, depending on manufacturer). It has been "leaked" that the microprocessor will actually
report the battery as "dead" after a certain number of cycles. I read this at several different places but was never able to confirm it with any kind of authority. I believe this COULD be true due to the inherently dangerous nature of Li-Ons. The technology has been known for 100 years, but Sony was the first one to make it commercially viable with the insertion of a microprocessor inside the battery to control both the rate of discharge and charge. Before this, an uncontrolled charge would result in the battery bursting into flames and exploding. (This has happened with some cell phone batteries, aftermarket stuff made cheaply without the safeguards in place.) This is why I will never leave my battery in the notebook on AC unattended for hours on end or overnight. All it will take is a failed microchip and your house could be toast. Part of the huge cost of these batteries is the liabiltiy in this inherently dangerous technology.

I believe the time is coming for something else to power our notebooks.
For the time being, Li-On is the most cost effective, but all it will take is one proveable accident and a massive lawsuit to change all that.

All this information was researched over a period of about 6 months from many different sources. The Battery University is very informative, just google battery university, it should come up. I also googled Li-On and read just about every technical piece I could come up with. The UofA library also yielded some interesting information.

[rgbyhkr]

I came across some of that same info about how to lengthen battery life. You're right, it is a PITA and that's too much trouble for me. I'm going to make use of the external charger and swap out the batteries and, after seeing the $99 price at Newegg, almost certainly pick up another 9-cell. That way I can extend the life of each battery and run the system a long tme without having to be near an outlet.

[Lostoutlaw]

Wow, that is the most informative post about batteries I have ever read in my life. Thanks for sharing your expertise!

James

[NaT]

A few observations from my experience with notebook batteries:

- If you attach the AC adapter and leave it connected for a long time, battery life will degrade substantially to the point that not working at all: I had two new T20/T21 and kept them plugged for a whole week while I was on business trip. There were in cool air-con room, so it wasn't heat problem. When I came back, both units' batteries were dead and need replacement. Luckily I got them for free since they were "IBM internal use" machines

- Full usage and full recharge elongates battery life: The power management also have an option to do this. It will continue to draw power from battery even if you plug your AC, until it reach some lower watermark when it will start to recharge back.

- The no. of cycles is reported from "smart batteries" with microchip inside. There is a certain watermark set to tricker the count, let's say under 70% (not sure the exact number) but your "actual" battery cycle may not based on that cycle but true charge/recharge cycle.

- I was told by IBM PC technician that even though it works, it is not recommended to operate Thinkpad on AC adapter alone without battery attached to the unit (bare mode). Not sure exactly why.

Should you have any comments on further experience, please share.

NaT

[mlykke]

Im surpriced of the "horror" stories some of you guys are telling about.
I've NEVER experienced anything like this.

Im currently using a three year old Dell Insprion 8200 with two batteries.
the compute rhas been used upwards of 16-18 hours a day and have OFTEN been running for weeks at a time as well.
And i still get over 3 hours of batterytime using both batteries(Beofre you say this is not much you should know that when it was brand new i only got around 4½-5 hours). And this is after three years of intense use without ANY caring for the battery at all.

And the story about batteries dying after a week is just a VERY unlucky case. There is NOTHING in a battery which couldnt handle that.

[brainpicker]

Don't charge your laptop "bottom down"... open the screen to make a 90-degree angle and lay it on it's side to dissipate some heat. I close mine and gently lean the top against the back of my sofa while charging. It serves the same purpose and puts little pressure on the screen or hindges. Either way, it works to reduce heat. Always plave a cellphone on it's side when charging the battery too. Same reason.

Yak

[rgbyhkr]

I received the replacement battery this morning. It was labeled as used, so I popped it in to check out the stats. Here they are:

Full Charge Capacity: 62.21Wh
Design Capacity: 71.28Wh
Cycle Count: 16
First Used Date: 2004-05
Manufacture Date: 2003-12-12

Definitely better than my old one and I guess on par with "average" capacity loss for one year of use.