Post by: Paddy on November 19, 2009, 11:06:35 AM
http://www.batteryuniversity.com/parttwo-34.htm
Clearly, my mistake is leaving my MBP plugged into the wall most of the time:
QUOTE
The worst condition is keeping a fully charged battery at elevated temperatures, which is the case with running laptop batteries. If used on main power, the battery inside a laptop will only last for 12-18 months. I must hasten to explain that the pack does not die suddenly but begins with reduced run-times.
Post by: daryl66 on November 19, 2009, 11:56:55 AM
QUOTE(Paddy @ Nov 19 2009, 12:06 PM) <{POST_SNAPBACK}>
Came across this in my travels yesterday - good info:
http://www.batteryuniversity.com/parttwo-34.htm
Clearly, my mistake is leaving my MBP plugged into the wall most of the time:
http://www.batteryuniversity.com/parttwo-34.htm
Clearly, my mistake is leaving my MBP plugged into the wall most of the time:
QUOTE
The worst condition is keeping a fully charged battery at elevated temperatures, which is the case with running laptop batteries. If used on main power, the battery inside a laptop will only last for 12-18 months. I must hasten to explain that the pack does not die suddenly but begins with reduced run-times.
FYI
Well my experience is exactly the opposite of that. I have 2 12" G4 Laptops. One is used as "Her" primary computer and the other is used mostly for travel. They are both over 60 months old with the original batteries, and we keep them powered up with the batteries in. According to "Coconut" both are over 85 percent of their original capacity. Admittedly neither has been put to the test just to see how long the batteries will stay charged however the one that travels has been used 2-3 hours on occasions.
I guess YMMV
Daryl
Post by: Xairbusdriver on November 19, 2009, 03:28:30 PM
It seems battery technology changes faster than we can. When I used Ni-Cads in RC flying, the trick was to never leave them with a low charge for very long. And never leave them with a full charge for very long. And never leave them with any particular charge for very long. Other than that, you could do anything you wanted.
That was called battery "memory."Newer types seem to have lost any memory and that's supposed to be good. OTOH, it appears that some managed to retain more brain cells than at first thought!
Maybe it's part of the 'exercise is good for you' fad(!) that leads some to report that 'exercising' the battery is good for them, also.
I suspect that most of us just don't worry about how we charge these things. I try to remember to let Judy's MBP run to shut down every couple of months. But I'm not sure it really matters. Although I think Apple suggests doing something like that, also.IMHO, batteries are part magic. They would usually tell you how much power is really available. Many devices will claim to tell you but I don't think the batteries pay much attention to those reports. It seems that batteries know when their use is critical and no replacements nor charging capabilities are available. And then...
But your quote includes the additional condition that is not good for any kind of electronic device, "elevated temperatures." Laptops are especially prone to this condition because of compact interiors and often not very heat conductive surfaces supporting them (or even covering them!). My only solution has been to spend ten bucks for a laptop cooling device. It has two USB fans and the four legs fold into its body for making it very easy to pack in the laptop bag. Luckily, I bought two of them. The first one started throwing fan blades causing vibration and slowing that fan until it was basically useless.
Post by: daryl66 on November 19, 2009, 06:45:13 PM
QUOTE(Xairbusdriver @ Nov 19 2009, 04:28 PM) <{POST_SNAPBACK}>
But your quote includes the additional condition that is not good for any kind of electronic device, "elevated temperatures." Laptops are especially prone to this condition because of compact interiors and often not very heat conductive surfaces supporting them (or even covering them!). My only solution has been to spend ten bucks for a laptop cooling device. It has two USB fans and the four legs fold into its body for making it very easy to pack in the laptop bag. Luckily, I bought two of them. The first one started throwing fan blades causing vibration and slowing that fan until it was basically useless.
Just another "FWIIW" comment. Once the batteries in my laptops are fully charged, the charging operation ceases. This can be confirmed by going to "about this mac>more info>power>". There is NO heat being generated from the battery or the charger . In the operating manual for the 12"G4 laptop. It states that the best way to prolong the battery life is to keep it plugged in.
Daryl
Post by: Xairbusdriver on November 20, 2009, 10:54:08 AM
And I don't think anyone is arguing that Apple has stated what you said in that manual. However, as you said that laptop is five years old, it could be that the battery in there is different than the one referred to in the link.
I guess one must choose to believe the info from the manufacturer, who has sometimes been in error, or trust a site with unknown credibility. Hopefully the opposite of "Damned if you do and damned if you don't!" 
You have certainly been successful with following Apple's instructions. My wife's ~year old MBP says to run the battery down till it shuts down the machine and then charge it. That's what I've been doing, mostly.
Plus the purchase of the cooling stand...the MBP is running 24/7 doing that Folding@Home stuff, so it is usually pretty warm. If it's not doing something like that, it shouldn't be operating with "elevated temperatures." OTOH, you might be surprised at what some temps are if you install some of the freeware apps that can show the various sensor values.
Post by: Paddy on November 21, 2009, 09:40:56 PM
http://blogs.techrepublic.com.com/helpdesk/?p=124
http://en.wikipedia.org/wiki/Lithium-ion_battery
In fact....Apple doesn't recommend leaving your laptop plugged in all the time either!
http://www.apple.com/batteries/notebooks.html