06-07-2005, 10:43 PM

I've been researching battery use and care for my Powerbook since I've got it in order to maximize it's life. Just wondering what everyone knows about it. I've heard many people say leaving it plugged in for months is fine. But from the Apple site, I am getting the impression it should be run down all the way at least once a month. They even have a note that it will automatically put on iCal to remind you to do so every month. I am going to college in August so then it will be plugged in and out probably daily, but until then I've just been leaving it plugged in. So I don't want to be doing the wrong thing.

Any thoughts are appreciated. Thanks.

06-10-2005, 09:07 AM

Originally Posted by TOYOTA

I've been researching battery use and care for my Powerbook since I've got it in order to maximize it's life. Just wondering what everyone knows about it. I've heard many people say leaving it plugged in for months is fine. But from the Apple site, I am getting the impression it should be run down all the way at least once a month. They even have a note that it will automatically put on iCal to remind you to do so every month. I am going to college in August so then it will be plugged in and out probably daily, but until then I've just been leaving it plugged in. So I don't want to be doing the wrong thing.

Any thoughts are appreciated. Thanks.

Don't worry about battery life. every once in a while let it drain down fully and recharge fully. batteries are to be changed every 2-3 years anyway. and PB batteries are not that expensive. I pre purchased an extra one, just because I tend to travel a lot, and need the extra juice. i also alternate the sue of the batteries to maximise the life.

06-12-2005, 01:03 AM

Yeah, the last thing to worry about is your battery. There is some terminal code that shows how much of the original charge your battery still can hold, But I can't remember it offhand. If you are really worried, just buy another battery, you can find them for $50, and put it in a box for a rainy day...

06-13-2005, 10:14 PM

Can you recharge it whenever or do you need to let it drain all the way first to maximize life?

06-15-2005, 05:27 PM

Bump?

06-15-2005, 05:39 PM

I think you're supposed to drain it completely before changing at least once in a while, otherwise keep plugged in whenever you can, try not to go through to many cycles too fast. That is, if you're worried about it.

06-15-2005, 06:27 PM

What type of battery is in the PB? NiMH? Depending on what type of cell it uses would determine battery charge care.. BUT IMO, on a laptop, it's the last thing I'd be worried about. Actually I wouldn't even put an ounce of thought into it.. When and if I killed it, I'd just go get another. But with any rechargeable battery, a once a month cycle of the cell would be good "care".

06-19-2005, 10:59 PM

Originally Posted by Tel

otherwise keep plugged in whenever you can, try not to go through to many cycles too fast. That is, if you're worried about it.

What damage would be caused by going through too many cycles too fast? I am going to college in August and will be probably be goign through cycles on a near daily basis.

Originally Posted by dstyrk

What type of battery is in the PB? NiMH?

Li-ion, correct?

I didn't think Li-ion was affected by how fast or slow you go through the charge cycles...

Thanks for your input!

06-19-2005, 11:05 PM

Lithium ion battery
(Redirected from Li-ion)
Lithium ion batteries (or Li-ion) have become very common and dropped in price recently. They provide one of the best energy-per-weight ratios of rechargeable batteries at present. They have succeeded nickel metal hydride and nickel-cadmium batteries in consumer electronics such as cellular phones and notebook computers.

Specific energy density: ~150-200 Wh/kg Volumetric energy density: ~250-530 Wh/L

Lithium-ion batteries have a nominal voltage of 3.6 V and a typical charging voltage of 4.2 V. The charging procedure is one of constant voltage with current limiting. This means charging with constant current until a voltage of 4.2 V is reached by the cell and continuing with a constant voltage applied until the current drops close to zero. (Typically the charge is terminated at 7% of the initial charge current.) Lithium-ion batteries cannot be fast-charged and typically need at least four hours to fully charge.

Li-ion batteries are not as durable as NiMH and NiCd designs, although they do not suffer from the memory effect, and can be extremely dangerous if mistreated. At a typical 100% charge level (notebook battery, full most of the time) at 25 degrees Celsius, Li-ion batteries irreversibly lose approximately 20% capacity per year from the time they are manufactured, even when unused. (6% at 0 °C, 20% at 25 °C, 35% at 40 °C. When stored at 40% charge level, these figures are reduced to 2%, 4%, 15% at 0, 25 and 40 degrees Celsius respectively.) Every (deep) discharge cycle decreases their capacity. The degradation is sloped such that 100 cycles leave the battery with about 75% to 85% of the original. When used in notebook computers or cellular phones, this rate of deterioration means that after three to five years the battery will have capacities too low to be still usable.

One great advantage of Li-Ion batteries is their low self-discharge rate of only approximately 5% per month, compared with over 30% per month and 20% per month in nickel metal hydride batteries and nickel cadmium batteries respectively.

Lithium ion internal design is as follows. The anode made from carbon, the cathode is a metal oxide, and the electrolyte is a lithium salt in an organic solvent. Since the lithium metal which might be produced under irregular charging conditions is very reactive and might cause explosion, Li-ion cells usually have built-in protective electronics and/or fuses to prevent polarity reversal, over voltage and over-heating.

The Li-ion battery required nearly 20 years of development before it was safe enough to be used on a mass market level. A unique drawback that we can see to the Li-ion battery is that its life cycle is dependent upon aging from time of manufacturing (shelf life) regardless if it was charged or not and not on the number of charge/discharge cycles. This drawback is not widely publicized.

A more advanced lithium-ion battery design is the lithium polymer cell.

Guidelines to prolonging Li-ion battery life

Unlike NiCad batteries or NiMH batteries, lithium-ion batteries should be charged early and often. However, if they are not used for a longer time, they should be brought to a charge level of around 40%. Never use the battery care functions some cellular phones provide for nickel based batteries. (This will deep cycle the batteries.)
Li-ion batteries should be kept cool. Ideally they are stored in a refrigerator. However, they should not be subjected to freezing temperatures. Aging will take its toll much faster at high temperatures. Keeping them in burning hot cars can kill lithium-ion batteries.
Buy Li-ion batteries only when needed. Look at the manufacturing date. That is when the aging process commenced.
When using a notebook computer running from fixed line power over extended periods, it is advisable to remove the battery and store it in a cool place.
Removing the battery from a laptop while it is plugged in is against manufacturer's recommendation for many laptops as it can cause permanent damage to the laptop since the power supply is designed to output a voltage assuming a battery is present. Therefore, when removing the battery from a device when it is plugged in, be sure that it is in an acceptable mode of operation.
[edit]

See also

battery (electricity)
[edit]

External links

Apple's guide to Lithium Ion Batteries
Battery University Site
Categories: Electric batteries

06-19-2005, 11:07 PM

That was taken from the Wikipedia widget.

Get it here