good use habits LiPo in laptop?

[zband]

I have a macbook air, which uses a LiPo (non-replaceable) battery. Because I wont be able to replace it as easily, any suggestions on good use habits to make it last as long as possible?

For example, should I recharge it only when it runs down, or is it better to recharge it as soon as possible?

Sorry one last question- do you see the capacities of LiPo increasing as fast as LiOn?

thanks

 

[wyager]

Don't worry too much about it, macbooks have literally the best batteries in the laptop market. My macbook is at 700 charge/discharge cycles and has 88% original capacity. The new batteries are even better. Just give the battery a "workout" every once in a while.

 

[jasonck08]

Don't worry too much about it, macbooks have literally the best batteries in the laptop market. My macbook is at 700 charge/discharge cycles and has 88% original capacity. The new batteries are even better. Just give the battery a "workout" every once in a while.

Really. Thats pretty incredable. I'm not a Mac guy myself, but is there special software that tells you how many cycles the battery has been through? Also are the cycles full discharge cycles or does a cycle count when you unplug the laptop for 10 minutes then plug it back in?

 

[wyager]

Really. Thats pretty incredable. I'm not a Mac guy myself, but is there special software that tells you how many cycles the battery has been through? Also are the cycles full discharge cycles or does a cycle count when you unplug the laptop for 10 minutes then plug it back in?

The macbook batteries have a very advanced built-in protection circuit. It includes a temperature sensor, acceleration sensor (I'm not sure why it needs that, LOL), etc.. The battery records all kinds of info about its usage, and that includes charge/discharge cycle. It also pays attention to the current draw and how long it lasts at what draw, which allows it to calculate its capacity every time do you use it. Also, those 700 charge/discharge cycles are calculated like this-
50% of the battery is used, then plugged back in.
35% of the battery is used, then plugged back in.
20% of the battery is used, then plugged back in.
That is 1.05 cycles (I think). Plugging and un-plugging do not change the number of cycles.
It records all of this stuff, and the computer has access to this information. I use iStat pro (a dashboard widget) to check my battery.

"Health" corresponds to %capacity. It will read "0%" if the battery is shot (I've only heard of that happening once-after my friend spilled water on his macbook).

The tilt sensor in the battery is especially cool, I've made a couple really cool screensavers with it.

 

[zband]

Really. Thats pretty incredable. I'm not a Mac guy myself, but is there special software that tells you how many cycles the battery has been through? Also are the cycles full discharge cycles or does a cycle count when you unplug the laptop for 10 minutes then plug it back in?

Nope its included in the operating system. Cycle count is performed through full discharge / charge cycles. Its a pretty cool program.

 

[jasonck08]

Cool. One of you should screenshot it.

 

[wyager]

Cool. One of you should screenshot it.

Screenshot what? I don't think there's an included app to monitor battery status... I already linked a pic to iStat pro, which can show you battery info...
EDIT:I see my pic is broken. Try this one:

 

[45/70]

I don't think there are any miracles involved here. Likely the battery is only charged to ~4.10 Volts/cell and the discharge is limited to something like 3.7 Volts/cell. This would extend the cycle life of the battery considerably, with minimal reduced capacity, unnoticed by most users.

As with most "miracles", the documentation, display information etc, while looking impressive, lacks any actual useful information which could be useful in determining how the system actually works.

zband, if I'm right, it really wouldn't matter a whole lot, how you use your MacBook Air. The setup will prolong the battery life pretty much whatever you do.

Dave

 

[ASheep]

They must have seriously improved the Li-Po batteries in the new macbooks... I have a two year old macbook pro 4,1 here is a screencap of my battery stats from istat pro:

I don't abuse the battery, but the laptop does get very heavy use...
Also, the accelerometer (sudden motion sensor as apple calls it) is used to protect the hard drive. If it senses sudden movement such as a drop, it parks the heads to avoid damage to the HDD.

 

[wyager]

They must have seriously improved the Li-Po batteries in the new macbooks... I have a two year old macbook pro 4,1 here is a screencap of my battery stats from istat pro:

I don't abuse the battery, but the laptop does get very heavy use...

Odd, I have a three year old macbook, I often run it down to about 30% every day (maybe lower) and the battery gets subjected to quite a bit of heat... It's a lot better off than yours.

@45/70

These things get pretty incredible power density as well (9 or 10 hours with a discreet graphics card, but I forget the exact specs-I think apple has them on their site), so I doubt they just "baby" the battery. The battery is one of the most expensive parts in an apple laptop.

 

[AnAppleSnail]

@45/70

These things get pretty incredible power density as well (9 or 10 hours with a discreet graphics card, but I forget the exact specs-I think apple has them on their site), so I doubt they just "baby" the battery. The battery is one of the most expensive parts in an apple laptop.

The top 0.1v and bottom 0.4v of a Li-Ion battery have very little capacity in them. That is, battery voltage plummets through those voltage numbers (From 4.2v to 4.1v and 3.6v to 3.2v) and doesn't really involve much power coming out. Lopping those out of the battery cycle drops something like 5% to 10% capacity and dramatically decreases cycle wear.

 

[wyager]

The top 0.1v and bottom 0.4v of a Li-Ion battery have very little capacity in them. That is, battery voltage plummets through those voltage numbers (From 4.2v to 4.1v and 3.6v to 3.2v) and doesn't really involve much power coming out. Lopping those out of the battery cycle drops something like 5% to 10% capacity and dramatically decreases cycle wear.

Could be then. But if that's the case, I imagine every laptop battery does that and that doesn't explain why macbook batteries are so much better.

 

[45/70]

Could be then. But if that's the case, I imagine every laptop battery does that and that doesn't explain why macbook batteries are so much better.

You make a good point here. With a laptop that runs for 9 or 10 hours though, a small decrease in capacity is likely going to go unnoticed. The tendency for laptop makers to get the most use time from their laptops (and thus utilize the maximum capacity the battery can deliver) is more pronounced for laptops that only run for a few hours.

Also, you do realize that Apple/Macintosh doesn't manufacture their own batteries, right? They source their batteries from the same places as everybody else.

Dave

 

[wyager]

Also, you do realize that Apple/Macintosh doesn't manufacture their own batteries, right? They source their batteries from the same places as everybody else.

Dave

:thinking:
I'm 99% sure apple has their own dedicated LiPo cell factory-they don't contract out to sanyo or whomever to make their cells. It's probably cheaper that way, as they basically own the mobile device market in quite a few countries. Plus, don't most laptops use 18650s or other li-ion cells?

 

[AnAppleSnail]

:thinking:
I'm 99% sure apple has their own dedicated LiPo cell factory-they don't contract out to sanyo or whomever to make their cells. It's probably cheaper that way, as they basically own the mobile device market in quite a few countries. Plus, don't most laptops use 18650s or other li-ion cells?

Apple recalls Sony-made batteries in 2006

Apple may use C-tech in 2009.

As far as I can tell, they once used Sony, and now won't say who provides their batteries. But they don't. It's expensive to manufacture batteries!

 

[wyager]

Interesting... I could have sworn that apple had their own battery plant... :shrug: Guess not. However, here's a question-with apple dominating portable markets with a very limited range of devices, can't they dump a lot more of R&D/manufacturing setup money in to one particular kind of battery than most companies? Just a thought.

 

[jasonck08]

:thinking:
I'm 99% sure apple has their own dedicated LiPo cell factory-they don't contract out to sanyo or whomever to make their cells. It's probably cheaper that way, as they basically own the mobile device market in quite a few countries. Plus, don't most laptops use 18650s or other li-ion cells?

They don't have their own factory. Some of their LiPo batteries are made by one of the largest LiPo battery companies in China.

I'd say more then 95% of laptops use 18650 Li-ion cells. The 18650 cell is the bread and butter for laptop batteries. That's why it gets so much attention and why we see capacities growing every year and now topping 3000mAh!

 

[spencer]

Do you think that Apple's new batteries are better than anything anywhere or are some of the RC lipos of similar quality and power density?

 

[jasonck08]

RC LiPo's are made for high discharge currents of ~20C. Apples batteries are made for low discharge currents of <2C. So I think its kind of hard to compare the two. I suspect Apples LiPo's have a decent amount more energy density then RC type LiPo's.

 

[CKOD]

Quick rundown of how to not kill laptop batteries:

Temperature:
High temperature is the harshest thing on battery life, (well next to overdischarging, but well designed system shouldnt overdischarge the cells...) If your laptop maker was a genious who decided it would be good to put a battery near the CPU and GPU if your laptop has one, then you have to be even more mindful of it then makers who put the hot stuff in the back, and the battery in the wrist rest.

Depth of discharge:
Deeper discharges "wear" the batteries more, so charge up whenever you can. However, leaving a laptop plugged in shoudn't do anything bad to the battery overcharging-wise, but most laptops automatically go to high power mode when they are plugged in, high power = high heat, see above.

While it wont hurt actual capacity, a bunch of shallow charges and discharges may allow your battery monitor to stray and get lost, so you may be reading 10% left when you have much more. Occasionaly, let the laptop run from a full battery till it shuts off. A complete discharge lets the battery monitoring circuit figure out whats going on again.