QUOTE(ginolo @ Oct 25 2009, 02:32 AM)
Quite a good explanation. But i must say that "Sometimes"(strongly emphasize) from 80% usage and charge till 100% doesnt count as a cycle. And same goes to 30% which i tried before. Guess what for my 2months mbp is only having 9 cycles? I bring my laptop everyday to school and use it w/o magsafe. Damn happy and very satisfy about the my battery life cycles and mh.
Added on October 25, 2009, 4:14 amhttp://eshop.macsales.com/shop/Modbook found a modded mac website. saw 2 tablet there. the price is really painful.
Oh ya, I fail to mention that the counting of charge cycles is really tricky business. For one, there's no proper standard to address these 'metrics' so one manufacturer accounts cycles differently from the other. Some move into more conventional methods as long as 100% potential charge has been discharged while others are more aggressive. The truth is a battery usually outlives the manufacturer's claims provided they are well maintained and always used. Remember heat? Heat is a very bad component for Li-Ion. Cause heat changes their structure.
QUOTE(MetalZone @ Oct 25 2009, 01:16 PM)
Sorry but I beg to differ in some aspects. A lithium-ion(cobalt)/lithium-polymer battery (used in laptops) doesn't "remember" how many charge cycles it has gone through. It is simply a figure the electronics count to keep track of the battery.
Li-ion's do not have any 'memory effect' (as you mentioned) unlike Ni-MH batteries (Nickel metal hydride) which do; and isn't actually old tech compared to Li-ion-cobalt; Just different types of battery chemistries for different purposes. NiMH's prefer to have a full charge and discharge cycle, but Li-ion's aren't too happy with that. Not doing a full discharge DOES NOT "waste" that charge cycle.
Having a full charge and discharge once in a while is fine (also recalibrates the electronics monitoring the battery) but avoid doing it on purpose ALL the time (unless that's really your usage cycle then by all means use what you invested for).
A battery charging circuitry doesn't use the temperature of the battery as a charging indicator, but rather as a shutdown and disconnect mechanism, coz if you overcharge or overdischarge a lithium-ion-cobalt, you may get what you call a "thermal-runaway" potentially with flames! Instead it uses voltage as an indicator, and it varies between different battery chemistries.
To quote a fellow flashaholic... (flashlight hobbyists in other words. we live on the edge of loose li-ion cells on our devices so we know the pros/cons and dangers of these little things)
he has summed it up pretty well:
Correct me if I'm wrong though.
Yes, Li-Ion does not have memory effect. I remember myself specifically mentioning that its not memory effect. As mentioned before, there are areas that aren't clearly defined in how cycles are accounted for. You're right, Li-Ion likes to be charged and discharged many times. Which is why it is perfect for today's electronics and usage lifestyles. Sometimes I wonder why Sony implements charging programs like they did for their VAIOs. There must be a reason.
And of course temperature is not the only parameter charging circuitry look for. They do have dB cutoffs, voltages, and negative dB inputs. What I was saying is that fundamentally, when a Li-Ion cell approaches a fully charged state, its temperature would shoot exponentially. That is the critical nature of Li-Ion, one that is dangerous and bad for its longevity. Sorry if I wasn't clear enough. Writing in the middle of the night does seem to be blurry hehehe...
This post has been edited by davidmak: Oct 25 2009, 04:26 PM