View Poll Results: Good Idea Battery Cover with Breather/Vent Holes

Voters
42. You may not vote on this poll
  • Great Idea

    14 33.33%
  • Horrible Stupid Idea... how dare you cut holes in my Pre!

    21 50.00%
  • Neither good nor bad

    7 16.67%
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  1.    #1  
    Since seido is making an extended back for their bigger battery, perhaps we can all get them to make a battery door with some breather/vent holes over the battery to allow it to cool off better. This would keep the actual temperature of the battery down and make it so you could get through a phone call without burning your hand... Anyone agree?

    Anyone have a spare back cover (those who bought a touchstone Im looking at you) to allow me to experiment with? I have a good CNC mill and it wouldnt be hard to test out.
  2. #2  
    I'm doubting that a few subtle holes would actually transfer much more heat than what we have currently, since the air would be pretty static (especially if it's covered by your hand in a phone call). I actually think my Pre is less warm in a phone call than my 755p was.
    Palm III-->Handspring Visor-->Sony Clie PEG-NR70-->no PDA -->Palm Treo 755p-->Palm Pre-->HP Veer
  3.    #3  
    Considering the large temperature differential, the non natural convection flow could actually be quite beneficial. If you hold you phone like I do, then the holes wouldnt be covered either. Itll be simple enough to test out in any case. Something along the lines of the holes covering the speaker would be sufficient (i am Mechanical Engineering PhD and I work on heat/mass transport research...)
  4. #4  
    Quote Originally Posted by gtkansan View Post
    Considering the large temperature differential, the non natural convection flow could actually be quite beneficial. If you hold you phone like I do, then the holes wouldnt be covered either. Itll be simple enough to test out in any case. Something along the lines of the holes covering the speaker would be sufficient (i am Mechanical Engineering PhD and I work on heat/mass transport research...)
    Well that certainly bests my qualifications to speak about the issue at hand. Where would you put the holes? Would you try to do it in such a way to as to allow air to flow through (in and out) as a result of the heat?
    Palm III-->Handspring Visor-->Sony Clie PEG-NR70-->no PDA -->Palm Treo 755p-->Palm Pre-->HP Veer
  5. #5  
    Great way to accumlate dust on the inside of your phone.
  6.    #6  
    I wouldn't want a flow through design, there would be no way to control directionality (without a microfan ).

    Just straight pinholes down to the battery surface. You can just think of it as a transport problem, in the normal case, we have a high temperature battery in contact with a plastic case. The heat must be conducted through the plastic (not a very good conductor) and then released by natural convection to the air.

    In the hole'd case, we would have a parallel heat transport mechanism, both the transport though the plastic as well as the air in direct contact with the battery surface. The air heats up (the battery is hotter than the outside of the phone) and expands driving a recirculating flow into and out of each pore. This would increase the effective heat transfer coefficient and thus the net result is that the battery (and the outside of the phone) would be at a lower temperature.

    For those not well versed in heat transfer, think of the battery as just a electrical resistor, it has current goign through it and thus puts out a given amount of heat (energy) per unit amount of time. If you stick that wire (assuming it is shielded) in air, or in water, the surface temperature of the wire will be MUCH cooler in the water than in air, because the heat transfer rate from wire to water is much greater than that from wire to air.
  7. #7  
    [QUOTE=jasonaward;1691179]Great way to accumlate dust on the inside of your phone. [/QUOTE

    another place for moisture to get in too..
  8. Mosbb's Avatar
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    #8  
    speaker holes should already do this. Have you guys noticed that the battery cover actually helps the speaker sound? Without the cover the speaker sound real low.
  9. #9  
    thin screen like on most speakers
  10. #10  
    Quote Originally Posted by Preman View Post
    speaker holes should already do this. Have you guys noticed that the battery cover actually helps the speaker sound? Without the cover the speaker sound real low.
    this is called the box effect. try grabbing an earbud and cupping it you hand creating a hollow chamber behind it. you ill notice the same thing
  11. Mikest's Avatar
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    #11  
    I like this holey idea. Then if it gets way to hot you can just pour some ice water right in.
  12. mtgmt's Avatar
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    #12  
    Quote Originally Posted by gtkansan View Post
    I wouldn't want a flow through design, there would be no way to control directionality (without a microfan ).

    Just straight pinholes down to the battery surface. You can just think of it as a transport problem, in the normal case, we have a high temperature battery in contact with a plastic case. The heat must be conducted through the plastic (not a very good conductor) and then released by natural convection to the air.

    In the hole'd case, we would have a parallel heat transport mechanism, both the transport though the plastic as well as the air in direct contact with the battery surface. The air heats up (the battery is hotter than the outside of the phone) and expands driving a recirculating flow into and out of each pore. This would increase the effective heat transfer coefficient and thus the net result is that the battery (and the outside of the phone) would be at a lower temperature.

    For those not well versed in heat transfer, think of the battery as just a electrical resistor, it has current goign through it and thus puts out a given amount of heat (energy) per unit amount of time. If you stick that wire (assuming it is shielded) in air, or in water, the surface temperature of the wire will be MUCH cooler in the water than in air, because the heat transfer rate from wire to water is much greater than that from wire to air.
    i think sounds logical and those that still dont quite get it think about the whirly bird on your roof, the heat makes it spin when no air is flowing~~

    good idea
  13.    #13  
    Quote Originally Posted by Mikest View Post
    I like this holey idea. Then if it gets way to hot you can just pour some ice water right in.
    Hahah interesting use....
  14. #14  
    BTW, a larger battery doesn't mean you need to disipate more heat. The heat generated by the battery would be roughly the same as with the regular battery, just over a longer period of time. It's not as though a double capacity battery generates double the heat.
  15.    #15  
    That wasnt my implication. Just that since they are building molds for extended battery covers, they have the inner snap connections all setup in CAD/3D modelers and can easily make some modifications to accommodate my suggestion.
  16. #16  
    And my implication is that it's unneeded. You're trying to add cooling for a problem that doesn't exist. The electronic components are designed to operate while warm (or even hot, depending on their specs).
  17. #17  
    Quote Originally Posted by gtkansan View Post
    Considering the large temperature differential, the non natural convection flow could actually be quite beneficial. If you hold you phone like I do, then the holes wouldnt be covered either. Itll be simple enough to test out in any case. Something along the lines of the holes covering the speaker would be sufficient (i am Mechanical Engineering PhD and I work on heat/mass transport research...)
    Wow. Nice. My father was an engineer @ IBM for many many years. I asked him this very question and he snickered @ me with this remark...

    "how many units do you think they're going to replace from sweaty palms, condensation, and dust?" kind of a good point but give me something to correct him. Please. He such a know it all... :-)
  18.    #18  
    First; my concern is for the comfort of my hand while on a call or using the browser, not for the electronics themselves.

    Second; despite design considerations taking the temperature into account, a lithium battery will operate more efficiently at a lower temperature than the blazing hot temp it does now when really chugging along. Cooling it off could prolong battery life, especially while using current intensive applications such as GPS nav, wifi browsing etc.
  19.    #19  
    As for the condensation, etc. Using holes only over the physical location of the battery itself, along with a simple line of a polymer/etc stripping surrounding the newly opened area would effectively seal away moisture and dirt for the most part. This is a quite common method of battery cooling in high draw research equipment that must be handled and operated in adverse conditions, so a little hand sweat is unlikely to be much of a problem.

    I suppose you could dunk it in a pool and that would kill it, but there are so mainy openings on the phone that it would die a quick death even without any more.
  20. #20  
    Seriously? Do you think holes will help this? I personally think you're insane unless you plan to add at least a heatsink to redirect the heat. The holes are a great idea (actually, not really), but I think you're seriously underthinking the issue if your idea is "comfort of use". Plus, maybe your battery gets "blazing hot", but mine certainly does not. Warm, sure... but not "blazing hot".
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