NEWS: Apple sued over hot iPad shutdowns
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From: Lloyd Parsons on 29 Jul 2010 12:00 In article <4c517df5$0$22092$742ec2ed(a)news.sonic.net>, SMS <scharf.steven(a)geemail.com> wrote: > News wrote: > > John Navas wrote: > >> Apple's iPad can shut down if it gets too hot, and Jacob Baltazar, > >> Claudia Keller, and John Browning are as mad as hell and aren't going to > >> take it anymore. > >> > >> Those unhappy iPadders have filed suit against Apple � and they're > >> asking the court to elevate their claim to class-action status. > >> > >> Their lawsuit, filed in the US District Court, Northern District of > >> California, alleges that "the iPad overheats so quickly under common > >> weather conditions that it does not function for prolonged use either > >> outdoors, or in many other warm conditions." > >> > >> ... > > > > > > So what's the problem? Makes a great coffee cup warmer. > > > > I worked on the Microsoft Tablet reference design and the Compaq TC1000 > tablet. The thermal engineering was very difficult, much more so than a > laptop. It has to work in both orientations, it has to be cool enough to > hold comfortably, and it has to be quiet. The initial goal was not to > have a fan, but there was no way to cool it under all possible > circumstances without the occasional use of a fan, unless we lowered the > processor speed to a level where the performance was severely impacted. > It was a much thicker tablet with more vent holes than the iPad. When I > saw the iPad I was impressed that they had been able to design it as > they had and still been able to deal with all the thermal issues. > > There are software workarounds for thermal issues. You run the processor > slower as the temperature goes up. It's not ideal, but it will work. > Probably the thermal profiles need to be tuned to prevent these shutdowns. > > What's strange about the lawsuit is that over-temp shutdowns should be > independent of the weather conditions, they should depend solely on the > temperature readings from the core and other temp sensors in the unit, > and a shutdown should only occur when other measures to lower the > temperature have failed. > > [alt.cellular.cingular removed, Cingular no longer exists] Why strange? It seems that the over-temp shutdowns are doing what they are supposed to do and don't often cause a shutdown. That it does when you put it in direct sunlight would certainly tax the heat control issues of any electronics device. If there ever was a place for loser pays lawsuits, this one should be at the top of the list. -- Lloyd
From: John Navas on 29 Jul 2010 13:16 On Thu, 29 Jul 2010 08:56:09 -0600, in <6Eg4o.46304$f_3.24456(a)newsfe17.iad>, "Todd Allcock" <elecconnec(a)AnoOspamL.com> wrote: >"SMS" <scharf.steven(a)geemail.com> wrote in message >news:4c517df5$0$22092$742ec2ed(a)news.sonic.net... > >> What's strange about the lawsuit is that over-temp shutdowns should be >> independent of the weather conditions, they should depend solely on the >> temperature readings from the core and other temp sensors in the unit, and >> a shutdown should only occur when other measures to lower the temperature >> have failed. > >How can it be independent of weather (or, at least, the ambient temperature >around the device)? The internal heat has to go somewhere, and it can be >drawn out of the device into a 70-degree F environment much faster than >into, say, a 90-degree one. No kidding. But this is Steven. -- John "It is better to sit in silence and appear ignorant, than to open your mouth and remove all doubt." -Mark Twain "A little learning is a dangerous thing." -Alexander Pope "Being ignorant is not so much a shame, as being unwilling to learn." -Benjamin Franklin
From: SMS on 3 Aug 2010 02:14 Todd Allcock wrote: > > > "SMS" <scharf.steven(a)geemail.com> wrote in message > news:4c517df5$0$22092$742ec2ed(a)news.sonic.net... > >> What's strange about the lawsuit is that over-temp shutdowns should be >> independent of the weather conditions, they should depend solely on >> the temperature readings from the core and other temp sensors in the >> unit, and a shutdown should only occur when other measures to lower >> the temperature have failed. > > > How can it be independent of weather (or, at least, the ambient > temperature around the device)? The internal heat has to go somewhere, > and it can be drawn out of the device into a 70-degree F environment > much faster than into, say, a 90-degree one. Actual shutdowns should never occur regardless of the weather. The temperatures at which shutdowns occur are very high compared to the ambient temperature. When you run thermal testing on a tablet in a temperature chamber there's actually very little difference in terms of the internal temperature profiles across the ambient temperature range. Internal temperatures depends almost entirely on how the system is cooled (forced air, passive air, heat pipes, etc.).
From: -hh on 3 Aug 2010 06:07 SMS <scharf.ste...(a)geemail.com> wrote: > Todd Allcock wrote: > > "SMS" <scharf.ste...(a)geemail.com> wrote: > > >> What's strange about the lawsuit is that over-temp shutdowns should be > >> independent of the weather conditions, they should depend solely on > >> the temperature readings from the core and other temp sensors in the > >> unit, and a shutdown should only occur when other measures to lower > >> the temperature have failed. > > > How can it be independent of weather (or, at least, the ambient > > temperature around the device)? The internal heat has to go somewhere, > > and it can be drawn out of the device into a 70-degree F environment > > much faster than into, say, a 90-degree one. > > Actual shutdowns should never occur regardless of the weather. The > temperatures at which shutdowns occur are very high compared to the > ambient temperature. When you run thermal testing on a tablet in a > temperature chamber there's actually very little difference in terms of > the internal temperature profiles across the ambient temperature range. > Internal temperatures depends almost entirely on how the system is > cooled (forced air, passive air, heat pipes, etc.). Agreed, but chamber testing classically doesn't also include the complexity of solar loading. YMMV to what degree you want to include this as 'weather', but it is certainly an environmental factor. IIRC, more insight can be found in AR 70-38: peak solar loading can add up to ~0.1W/cm^2 to an exposed device. Subsequent surface temperatures can be +25C greater than ambient, and IIRC, the "becomes intolerable to touch (5 seconds exposure)" threshold is +145F. -hh
From: SMS on 3 Aug 2010 09:44
-hh wrote: > SMS <scharf.ste...(a)geemail.com> wrote: >> Todd Allcock wrote: >>> "SMS" <scharf.ste...(a)geemail.com> wrote: >>>> What's strange about the lawsuit is that over-temp shutdowns should be >>>> independent of the weather conditions, they should depend solely on >>>> the temperature readings from the core and other temp sensors in the >>>> unit, and a shutdown should only occur when other measures to lower >>>> the temperature have failed. >>> How can it be independent of weather (or, at least, the ambient >>> temperature around the device)? The internal heat has to go somewhere, >>> and it can be drawn out of the device into a 70-degree F environment >>> much faster than into, say, a 90-degree one. >> Actual shutdowns should never occur regardless of the weather. The >> temperatures at which shutdowns occur are very high compared to the >> ambient temperature. When you run thermal testing on a tablet in a >> temperature chamber there's actually very little difference in terms of >> the internal temperature profiles across the ambient temperature range. >> Internal temperatures depends almost entirely on how the system is >> cooled (forced air, passive air, heat pipes, etc.). > > Agreed, but chamber testing classically doesn't also include the > complexity of solar loading. YMMV to what degree you want to include > this as 'weather', but it is certainly an environmental factor. > IIRC, more insight can be found in AR 70-38: peak solar loading can > add up to ~0.1W/cm^2 to an exposed device. Subsequent surface > temperatures can be +25C greater than ambient, and IIRC, the "becomes > intolerable to touch (5 seconds exposure)" threshold is +145F. Since you cannot use a tablet under direct sunlight, solar loading is not all that relevant, though I suppose that a tablet could be on while not being used, and be left in direct sunlight. In any case, since the iPad's specified upper temperature limit for ambient temperature is 95 degrees F, the question is whether it's shutting down below that. If not, then the lawsuit is groundless since it's operating within spec. It's not unreasonable for users to expect a tablet to operate at higher temperatures, but they should have checked the specs before buying it for outdoor use in hot climates. |