battery time troubles and resets

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coius's picture
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Joined: Aug 25 2004
Posts: 1975

g'day. I have an iBook 1.2 that is giving me some *weird* times and percentages. I want to try something, and i was to know if there is a program for OS X that i can use to keep the machine totally on so that I can drain the battery fully and reset the internal Battery circuitry. It's just a hunch that something is messed up inside the battery.

I have already gone thru the routine things like reseting the power manager, reinstalling the system, and resetting pram (trust me, i have been trying this stuff for a month) and i want to know if there is a way of FULLY draining the battery where the circuitry is totally kaputz (electrical charged wise) so that i can start the battery with the internal circuitry renew. I know it's not the cells. I have had it for a year, and my friend who has an ibook with the same year, has used his battery a lot and it's in better condition than mine, in which i HARDLY use the battery. Also, when i *do* use the battery, i make sure it does a whole cycle before plugging it back in. Right now, it lasts anywhere between 45mins to 1.3Hours on automatic (with not much load) but sometimes i will get up to 2 hours on full load (high power usage)
I know it's not my power manager, as i have tried another battery.

What can i do, oh 'critter guru's?

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Jon's picture
Jon
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Joined: Dec 20 2003
Posts: 2804
Not using the battery much an

Not using the battery much and doing the full cycle may have actually harmed the battery life. LiON batteries should not be fully discharged, and should be left connected to the charger unless they are going in for long term storage. Also, the general temperature they are used/stored at will have an effect on battery life. I've still got over 70% capacity on my original 2002 iBook battery, and I have very rarely let it run down to the point of the laptop going into low-power sleep, let alone fully running out of juice and shutting off. I always leave it plugged in to the charger, and several times a week I use it for an hour or more on battery. I can coax over 3-3.5 hours from it if need be.

A full drain on a LiON is a very bad idea.

http://www.apple.com/batteries/notebooks.html
http://docs.info.apple.com/article.html?artnum=86284 - Apple Battery Calibration procedures

Advice from a post in the Apple Store page for the 12" iBook battery:

Quote:

* 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 cause by heat rather than charge / discharge patterns.

* Batteries with fuel gauge (laptops) should be calibrated by applying a deliberate full discharge once every 30 charges. Running the pack down in the equipment does this. If ignored, the fuel gauge will become increasingly less accurate and in some cases cut off the device prematurely.

* 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 dates. Do not buy old stock, even if sold at clearance prices.

* If you have a spare lithium-ion battery, use one to the fullest and keep the other cool by placing it in the refrigerator. Do not freeze the battery. For best results, store the battery at 40% state-of-charge.

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moosemanmoo's picture
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Joined: Aug 17 2004
Posts: 686
That sounds very unusual to m

That sounds very unusual to me, but trying to find a way to fully discharge the battery is definitely not a good idea. As far as I know, lithium batteries will die permanently if they are over-discharged. It's possible that part of your battery is damaged and simply won't work anymore, or the PMMU could just be confused. Using the computer until it goes to sleep and won't wake up would always reset my battery's power manager; have you tried that?

My original 867MHz 12" Powerbook's battery is at 94% of original capacity according to Coconutbattery and estimates 5:40 left using very frugal settings and 2:30 left with maximum performance, just for the record.

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Joined: Oct 22 2006
Posts: 1
This sounds a bit nuts but my

This sounds a bit nuts but my son told me about it and I finally decided that I'd try it. I put a lithium ion battery that would no longer charge(dell laptop) in the freezer for two days. I thawed it out and put it in the laptop. Lo and behold it started to charge. It took two trys to get it to 100% but it got there and seems to be discharging normally now. It's been running for 1.5 hours and still has 48% left. I have another dead laptop battery that I put in the freezer earlier today. I'll pull it out on Tuesday and see what happens.