The interest surrounding the iPad overheating meme isn’t vaning. Quite the contrary, folks are eager to get to the bottom of this thing. As we hold our breath for today’s definite findings of “a battery of tests” conducted by Consumer Reports, a display expert sheds more light on how an improved LED backlighting system on the iPad’s Retina display contributes to Heatgate and, specifically, the tablet’s run time.

You’ve already seen heat maps which prove that the new A5X chip with its jumbo-sized quad-core GPU is the biggest heater in the new iPad. That said, its souped up LED backlighting is actually the No. 1 factor leading up to a faster battery drain and is partly to blame for the gizmo’s five-degree Celsius temperature increase

You may not have known this, but the display normally consumes about 50 to 60 percent of the total tablet power, according to DisplayMate. Due to four times the pixels over its predecessor (264 pixels per inch versus just 132 pixels per inch on the iPad 2), the new iPad needed a more powerful LED backlighting system that could blast light through the denser pixels and make it come out.

Now, DisplayMate estimates that the number of backlight LEDs has roughly doubled from 36 on the iPad 2 to an estimated 72 to 82 on the new model. Note that the LEDs in the new iPad are for the backlighting only (the pixels are LCD). Though the gizmo sports a new battery with 70 percent larger capacity, it’s still insufficient to offset the increased power consumption of those extra LEDs that suck two and a half times more juice than on the iPad 2.

As a result, running your iPad at full brightness drains the battery noticeably faster. Specifically, setting the maximum brightness reduces battery life by roughly 20 percent compared to the iPad 2, DisplayMate found out. They also concluded that a brightness level of about 50 percent matches the iPad 2’s run time.

Dr. Raymond Soneira, president of DisplayMate Technologies Corporation of Amherst, N.H., explained in an interview with CNET:

So, at full brightness the new iPad lasts 20 percent less than the iPad 2. But in the middle range, the new iPad runs essentially at the same running time as the iPad 2. And, in fact, that’s the way Apple delivers it and that’s probably the typical setting.

Soneira pointed out that “the typical setting” entails the brightness slider set at 36 percent. This is likely too dark a setting for most folks, but the important thing is that the new iPad matches its predecessor’s run time in the middle range.

Another side-effect of full brightness: The battery has to push out more power so it gets warmer. And because it takes up virtually all the space inside the device, the battery spreads heat pretty much evenly across the iPad’s back. Good thing the innards of the iPad are housed inside an aluminum case, Soneira tells Kara Swisher of the AllThingsD blog:

That aluminum back is there to help with the power heat dissipation of the electronics, but metals at room temperature often feel cold to the touch because of their high thermal conductivity. So when the iPad is on its additional warmth helps take the chill off.

None of the above comes as a shocker, of course. All devices sporting an LCD display with LED backlighting suck more juice when you crank up the brightness level. It’s just that the effect is more pronounced on the new iPad due to its battery-demanding display and the much more powerful LED backlighting system.

If you’re eager to learn more about why the new iPad gets warmer, why it doesn’t matter and how it’s been blow out of proportion, check out our yesterday’s feature on the subject.

By the way, who runs their iPad at maximum brightness, anyway?

  • Who the heck use full brightness? I mean, if I turn either my iPad 1 or 2 to full brightness, I’m almost blinded. A few, very dark games has prompted me to momentarily turn up the brightness, but not full-time. Half is pretty ok, though I usually have them at about 35-40%.

    • Dan

      I always fun mine at full brightness 🙂

      • wow, you must be blind…

      • Dan

        not at all, I just prefer it like that, might be because I use my iPad where there’s a lot of sunlight (my home has a lot of windows). I’m too lazy to adjust it when I go somewhere darker.

    • Ah yah. The old “stop holding it that way” solution 🙂

  • Dan

    All of these issues are minor, but still, I’m happy I waited. I imagine all of these issues will be ironed out for the next generation device.

    • I am sure there will be issues on the next one too. This really is not a problem. I keep mine probably about 60-70% brightness and the battery life is fine.

  • Mine is ALWAYS at full. Same with iPhone

    • Kok Hean

      Get a flashlight.

  • ST

    I really hope the article title is sarcasm. Who didnt think the screen wasn’t the largest battery drain? That’s like being surprised the screen on your TV uses most of the power… Really!? The use of Heatgate is sensationalism at its worst.. I can’t tell the difference between my iPad 1 and my new iPad. Even the “tests” show its only 10 degrees more than the 2. Is the news cycle so boring everyone has to dig for trash? Anyone who passes on the new iPad *just* because of this supposed “Heatgate” needs to hold your breath because pollution has gone up a small amount from last year in many places.

  • DA If i play my car radio full blast while car is off. my battery will die fast also. whats there point

  • OR …… “The New iPad lasts 20% more when brightness is turned lower. ”
    FTFY Apple. My job is done here 🙂

  • Anonymous

    The whole “heatgate” thing is just retarded. Who the hell cares? Devices are all getting hotter, try running the Transformer Prime or the Galaxy S II for more than ten minutes on Dead Space or whatever and it’ll heat up like an oven. It’s a side effect of having advanced technology before their time; another year and they’ll have refined the tech, just like they’ve already refined dual-core processors with stuff like the new OMAP and S4 processors.

    Anyways, unless you’re running a benchmark for 30 minutes straight you’ll barely notice it. The thing isn’t just blown out of proportion, it shouldn’t even be considered in the “proportions” in the first place (unlike antennagate).

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  • Anonymous

    “By the way, who runs their iPad at maximum brightness, anyway?”

    Me. iPad and iPhone.

  • What à b*llshit post. Alll those people complaining about heating and pore battery life with full brightness on. This has nothing to do with problems on new iPad, but rather people always in the need of complaining about something.
    I meen both my iPhone or iPad heats up when it charging or used excessively. And also both have the “issue” that my battery drains mutch faster when on full brightness that’s why I always have it set at 35 to 40 % max.
    What a “SHOCKER” !!!
    Are you also wondered why your car battery drains faster when you put your music on high volume without having the car running? Asking for more power equals more power consumption! A real schoker indeed…


    • Jonathan Bishop

      @Noisebag – What is a ‘schoker ?’