Ask LH: How Can I Maximise Notebook Battery Performance?

Ask LH: How Can I Maximise Notebook Battery Performance?

Hi Lifehacker, I recently bought an Asus U31SD, and one of the things that I love about it is the 10-hour battery life. How can I keep my battery in good condition for as long as possible? Am I better off keeping it plugged in whenever I’m near a power outlet? If I do unplug it, should I try to run the battery flat before charging again? There’s a lot of conflicting advice out there regarding battery care. Thanks, All Charged Up

Dear ACU,

We’ve covered this topic in the past, looking at both how discharging your battery too often can actually reduce its performance and ways to enhance general battery performance, so we’ll point you straight back to those posts rather than repeating ourselves.

That said, it’s worth reiterating that the widespread belief that you should always let batteries fully discharge is an unhelpful oversimplification with modern batteries. It’s also important to recognise that ultimately, battery performance will degrade — for now, it’s essentially an inescapable fact of physics. You can slow the process by avoid too many recharge cycles and ensuring your machine doesn’t run too hot, but we haven’t yet reached the point of an eternal battery.


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  • I spoke to my mate who is an electrician, he stated that the amount of smart technology invested into the batteries today that it ultimately doesn’t matter if you cycle your battery (plug then unplug) or keep it plugged in continuously.

    • I think that’s probably a bit of an over-simplification.

      From my (small) understanding, the main things that degrade both service life and discharge useage time of a li-ion battery is continuing to charge the battery once it’s reached capacity and running the battery flat.

      In the case of the former, most equipment is able to sense when the battery is full and cease charging (ie laptops and modern cordless drills etc). I’d imaging this is the type of circumstance your mate was referring to.

      Other (and cheaper) equipment will continue to pump voltage into the battery its charging though – which can be disasterous to how long the battery will survive for before it no longer can hold a charge.

      In the case of the latter (fully discharing batteries on a regular basis) – I kind of don’t see the point in using batteries, if you can’t use them to their full potential. My approach here is charge as regularly as I can, and don’t skip a charge on your device simply because it’s “not full flat yet”; but by the same respect, I’m not going to loose any sleep on the occasions I do run a battery dry.

      • Lithium batteries last longer if not full discharged. However, the electronics built into them keeps track of how much charge there is, so as to know when to turn off the charge, and when to shut off the computer/appliance to prevent too deep a discharge (and to tell the user how much life there is). Over time, the calibration of this ‘fuel gauge’ will drift, and the battery will appear to have a lower capacity. A full discharge-recharge cycle re-calibrates this, and is recommended every few months.

        • As I understand, it fully discharging a lithium based battery alters the chemistry so that it significantly reduces its charging capacity.
          They work really well though when you charge them often -when they’re only half full etc, rather than ever fully letting them discharge.

          The older Cadmium style were the opposite though- you SHOULD fully discharge them and NOT charge them when half full etc or that would reduce their capacity.

          That’s a real simplification, but that’s what I’ve read many times.

  • Li batteries like living at between 80-20% charge. *Don’t* fully discharge it too often, you’ll increase the wear much faster.
    And, as Angus said, try to keep it cool. If you can, elevate the back if you’re using at your desk, plugged in for ages.
    In fact, if it’s going to be plugged in for 12+ hours, pull the battery out when it gets to 90% or so and plug it back in when you’re heading out.
    My 1005pe is 15 months old, has had 400 charge/discharge cycles, and wear is at around 7% according to BatteryBar.

  • Battery discharge cycles have changed alot over the last 10 years. Prior to all devices (portable) sporting a lithium based battery, we were using NiCad batteries. These batteries had a ‘memory’ meaning that an incomplete charging/discharging cycle would lead to max charging current would be reduced. This however is not the case with lithium batteries and adopting a ‘full charge, full discharge’ habit is of little use on modern devices. Lithium based batteries will naturally however reduce in maxmimum storage power, usual life span of only a few years; hence when most portable consumer electronics have warranties under 24months.

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