Keeping my unibody on charge: hampers battery life, or enhances it?

Now before you say anything, I know that keeping a battery on charge after it is fully charged can decrease its battery life by 30%, but I also know that Apple's batteries automatically stop charging when they have reached 100%, wait till the battery drops to 97%, and then start charging again.

I need to know if the battery life will degrade if I keep the laptop on charge... Any help?

 

How do you know that?

 

My 17" uMBP has been on charge for about 4 months. Battery health at 100%.

 

It is known that Li-polymer and Li-on batteries will degrade in time even if you do not even use the battery. So no matter what you do, it will eventually degrade to a point where it becomes useless. This depends on charging habits, number of discharges, temperature etc.

That said, the latest Unibody batteries have been very good. Infact, my battery has gone through 270 Cycles since I got the system in October, and the Health is 98%.

 

That simply isn't true. Many people use notebooks as desktop replacements and need to keep them plugged in.

 

I meant a simple battery that is kept on charge will degrade because of overcharging. But I need to know if MBP (late 08) batteries have a method of preventing that or they are the same.

Oh and what you said made no sense because he wouldn't need a battery if it's alway plugged in.

 

my 17" SR MBP (2007) is almost 2 years old. i use it as a desktop replacement of sort, and has almost always kept it plugged in all the time. the battery is still at 100%. although on one occasion after like about 6 months of me not calibrating the battery; it did drop to about 88%. discharge it, recharge it; voila! 100%.

 

And your statement isn't making sense either. So what do people do with the latest Unibody MBP's with built in battery that want to use it as a desktop replacement and keep it plugged in? BTO it without the built-in battery?

 

Apple laptops do not charge your battery unless it needs to charge it.. so it does NOT keep charging the battery just because its plugged in.... so the whole point is useless. If you battery is fully charged and you have it plugged in, it is NOT trying to charge your battery still, and not doing anything to hurt your battery.

 

Still, 100% today may not be the same as 100% when the macbook was new. It slowly degrades regardless of what you do.

 

But the point is that keeping the computer plugged in does not degrade the battery faster than if you do cycles.