So you've got a HUGE battery life. How can you make it last?


gp32rich

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Nice article over at El Reg giving tips on recharge cycling, storage and usage.


Overview:
Mobile phone model - charge it up, run it down : Good
Laptop model - charge a little, use some, run on mains, top it up, etc : Bad
Top tip: Keep it cool!
 
Wait, why are those labelled laptop and mobile phone, but also bad and good?
Is there a difference between what's good for laptops and what's good for cell phones?

I usually just leave both of mine plugged in, but occasionally I take my laptop somewhere and run it down partially.
 
lulzfish said:
Wait, why are those labelled laptop and mobile phone, but also bad and good?
Is there a difference between what's good for laptops and what's good for cell phones?

I usually just leave both of mine plugged in, but occasionally I take my laptop somewhere and run it down partially.

You want to cycle the battery at least once a month. This helps its capacity stay higher for longer.
 
I heard that li-polis and li-ions last longer if you don't wait till they're empty before charging
 
anexanhume said:
You want to cycle the battery at least once a month. This helps its capacity stay higher for longer.
I've seen a lot of conflicting information on this, but I think the consensus on this is that this is not good for Li-ion batteries, but may be done once in a while to recalibrate the charge-related information provided by the monitoring circuitry (providing the appearance of a change, even though it doesn't affect the actual capacity).
 
anexanhume said:
You want to cycle the battery at least once a month. This helps its capacity stay higher for longer.

That only makes sense for 'smart' laptop batteries that have capacity measurement circuitry *in the battery*; apparently some can get confused after a while. The Pandora battery doesn't have anything like that, so don't bother cycling it.

LiIon/LiPoly lose capacity fastest when they're both hot and fully charged. You don't need to worry about the heat - this isn't a laptop trying to dissipate 100W at all times, it won't get more than slightly warm. And it's a handheld, so you likely won't be using it tethered (and therefore fully charged) all the time. Just use it normally, and you should be fine.
 
Peter R said:
There is nothing wrong with using a bit of a laptop batteries charge and then plugging it in at all. These aren't Ni-Cd cells.
In the long term - yes, there is. It's the main reason laptop batteries lose significant capacity after 18 months and mobile phones last for much longer.

lulzfish said:
Wait, why are those labelled laptop and mobile phone, but also bad and good?
Is there a difference between what's good for laptops and what's good for cell phones?

I usually just leave both of mine plugged in, but occasionally I take my laptop somewhere and run it down partially.
It's the recharge method that's labelled, not the battery.
Mobile phones are generally drained to 10% before being charged. Laptops are regularly topped up. Combined with the heat generated - you lose battery capacity.

If you're not using the battery for a while discharge to around 50% before storage

Here's the link: http://www.reghardware.co.uk/2009/05/07 ... aintenance
and another: http://www.apple.com/batteries/notebooks.html
 
The Register is reputable enough.
I bought an extra battery for my laptop, it still lasts around 2.5 hours, the other one was taken to Psych lectures 5 times a week for a semester and is down to the 20 to 40 minute range.
 
gp32rich said:
It's the main reason laptop batteries lose significant capacity after 18 months and mobile phones last for much longer.

Actually it's the heat generated by the device that's the major culprit, not the charging profile (although that does have an effect). Laptop manufacturers emphasise charging profile because they can't do much about the heat.

That apple site says to try and keep the laptop at 22degC. HA! I guess you won't be wanting to switch your macbook on then.
 
pelrun said:
gp32rich said:
It's the main reason laptop batteries lose significant capacity after 18 months and mobile phones last for much longer.

Actually it's the heat generated by the device that's the major culprit, not the charging profile (although that does have an effect). Laptop manufacturers emphasise charging profile because they can't do much about the heat.

That apple site says to try and keep the laptop at 22degC. HA! I guess you won't be wanting to switch your macbook on then.
Mmm. That makes sense. And why laptop cooler plates are a good idea.
El Reg said:
so if your notebook's like that, consider buying a cooling stand to help draw heat away from the machine and battery. Don't keep your laptop in a hot car cabin, or in direct sunlight.
So - no solar panels on a laptop anytime soon, eh?

Keeping the battery charged AND hot (ie. using the laptop plugged to mains while running) has a devastating effect on capacity (green trace)...
Keeping it around 40% and hot is only poor (blue trace)
battery_2.png

This doesn't show what happens when used 'optimally', ie. charging only when necessary.
 
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