Am I a Lunatic, or Has 240V Given Us More Battery Power?

Malta uses the (to me, cartoonishly large) British 240V, three-pin electrical standard. We have sundry adaptors for our North American devices, including a World Travel Adapter set from Apple.

Julie and I both have aged 12″ Apple PowerBooks. Over the past three days, we’ve both independently observed that the 240V power has improved our laptops’ battery life by about 20%.

Is this even possible, or are we smoking too much of the Maltese crack? Yes, my knowledge of elementary electromagnetism is that poor.

On a related note, I’ve had very mixed feelings about Apple’s set of adapters. They work as advertised, but they arrived completely unlabelled. There’s six of them, two of which look pretty much exactly alike. The newbie traveller would have a hard time deciding which one to bring to, say, Poland, Singapore or New Zealand.

This oversight really surprised me, as Apple’s stuff is usually incredibly usable. I’d have thought labelling the various plug adaptors would have been a pretty obvious move.


  1. Apple is prone to avoiding wording on some devices, so they can avoid having to create separate ones for different markets.

    And while from a strict electrical standpoint there should be no difference in charging an old-style “dumb” battery through an adapter, newer batteries used in computers have their own chipsets and regulatory circuitry which help optimize charging and discharging. (For my MacBook, Apple just released a firmware update FOR THE BATTERY to improve some problems with their performance — each time you put a new battery in the laptop, the updater flashes the ROM inside the battery itself.)

    So it’s possible that the 240V power allows the regulatory circuitry to work more efficiently and get a better maximum charge out of your old battery, whereas it might make no difference in a newer, fresher one.

    But I’m no electrical engineer either, so I’m merely speculating.

  2. Well, I *am* an electrical engineer and I can attest to the fact that neither a 110 or 240V feed into a Powerbook adaptor will make any difference to the 19V (or so) that it generates for use by the Powerbook itself.

    That’s right, the Powerbook sees a low DC voltage, as opposed to the variable AC voltage that is presented at the outlets in the wall. How this is generated is of no interest or influence to the Powerbook’s battery charging circuitry. Sure, the ‘brick’ adaptor in the cable will be doing different stuff in order to generate that low DC voltage, but it isolates the Powerbook from the different AC voltages that *it* sees.

    S’funny, I’ve always looked in horror at the way that a mains plug almost falls out of a US style socket under its own weight. A UK 3-pin plug has a feeling of security which can only be aligned with our battleships of old, or maybe the Tower of London or the Queen’s own inpenetratable underwear 🙂

  3. No idea about the battery question, but just a warning. Malta does not always have a consistent power supply, so invest in a good surge protector. I know several people who have had their computers hurt by Malta’s not-infrequent power variations.

  4. Having grown up in the us and emigrated to the uk, the plugs also seemed cartoonishly large for a bit, but i grew to really appreciate their sturdiness – eu plugs as well. And it’s a good thing. Getting buzzed by 110 is an altogether more frivolous experience than the 240 jolt hehe. However, my #1 favo(u)rite thing about UK plugs is the fact that they all have their own switch – something that afaik is unique to the uk. Very useful! The tradeoff is the complete lack of sockets in bathrooms. A paranoia too far imho 😉

  5. Elliot, the lack of sockets in a UK Bathroom is to stop people killing themselves and remembering that it can take as little as 6mA to stop the human heart… The most you will see in a GOOD UK bathroom is a Shaver Socket operating 110/240v with a serious amount of circuit protection built in just in case….!

    In the UK, Building Regulations state that a power socket in any room that has running water should be at least 1.5m from the water to try and stop people handling both at the same time!

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