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  • Mini-ITX + External Laptop Battery

    Was wondering, since many mini-ITX mobos now have direct DC Inputs, has anyone tried using an external Laptop battery as a "buffer" so that the PC doesn't draw power directly from the car battery?

    One thing I have an absolute fear of, is walking away from my car and coming back to find the PC has drained the battery somehow.

    I'm looking at an ASUS AT3IONt-Deluxe mobo(Discontinued I know, but the RCA Outputs make it perfect for car applications ) which unfortunately has the ATX power connector removed, so the only option is to use the built-in 19V DC input.

    So basically I would have something like this:

    12V Car Battery -> DC-DC Regulator ->19V External Laptop Battery -> DC Mobo Input with a regular oldskool shutdown controller somewhere in there.

    The idea here, is the DC-DC controller is connected to the car "Accessories" power (don't know if it's known as something differently in the US) so car power is only used to charge the 19V Laptop Battery when car is on.

    As soon as power is cut, hopefully, the shutdown-controller sends the signal, and the PC gracefully shuts down using the Laptop Battery for power. At worst, the PC ignores the signal, drains the Laptop Battery completely then dies a quick, horrible death :P
    But atleast it doesn't kill the car battery in the process.

    Ideally, if there was such a thing as an External Laptop Battery which has a USB connection so that the machine recognises it as a UPS or regular Laptop style battery, the computer could be made to power off using the built-in Operating System power options. This is a better option since OS shutdown controls have the ability to force through hung programs and similar which shutdown controllers can't do. Ever hit the power button on your PC only to come back 5 minutes later and there's a "please save your document first" or similar holding it up?

    Essentially what I'm trying to create here is like a laptop by combining a mini-ITX board and putting together a self-contained Li-Ion UPS which can be charged from an external power source (in this case, the car battery).

    Any thoughts, or ideas on how to improve this?
    Sorry about the epic post btw..

    NOTE: When I say "External Laptop Battery" I don't literally mean a battery removed from a laptop. You can get external self-contained battery packs which are designed plug into a laptop and act as a supplemental power supply by plugging into the DC Input to give you an extra hour or so of juice.
    See here:
    http://www.batterygeek.net/Laptop-Ta...-Packs-s/1.htm
    2004 HSV Clubsport M6
    Gear: i3 4130T, 8GB DDR3, ASRock Z87E-ITX, Noctua cooler, PicoPSU 150W, OpenUPS + SLA battery, 2DIN Samsung 7" screen with ITX enclosure, Win8 64 Pro

    Progress: [||||||| ] 80% - Planning done, Parts aqcuired, Benchtesting at 50%

  • #2
    Usually it's called a 2nd 12V battery plus a converter (plus a $5 "smart" isolation relay & fuses).

    Why - because a lap top battery is expensive, and much smaller. It may not last as long as the internal battery.

    And if you a worried about draining the car battery, a cheap $20 low voltage cut out will solve that, else a simple timer circuit.

    Comment


    • #3
      Originally posted by OldSpark View Post
      Usually it's called a 2nd 12V battery plus a converter (plus a $5 "smart" isolation relay & fuses).

      Why - because a lap top battery is expensive, and much smaller. It may not last as long as the internal battery.

      And if you a worried about draining the car battery, a cheap $20 low voltage cut out will solve that, else a simple timer circuit.
      A 2nd 12V battery is all well and good, but they're bulky and WAY overkill for just a shutdown buffer. A small external laptop battery can also be hidden easily and has all the relevant charging circuits contained.
      2004 HSV Clubsport M6
      Gear: i3 4130T, 8GB DDR3, ASRock Z87E-ITX, Noctua cooler, PicoPSU 150W, OpenUPS + SLA battery, 2DIN Samsung 7" screen with ITX enclosure, Win8 64 Pro

      Progress: [||||||| ] 80% - Planning done, Parts aqcuired, Benchtesting at 50%

      Comment


      • #4
        Ah - you didn't say just a shutdown buffer...

        So a $20 double cigarette-packet sized battery is way overkill and too bulky. Rats!

        Oh well. It sounded to me as if you wanted a independence from the car battery (when the car isn't charging) and a graceful shutdown which - from your OP - was based on the laptops internal battery and the typical UPS signalling.

        Keep in mind that your external battery will probably be a higher voltage than your internal battery.
        It will need protection from over discharge.
        It will need to be charged.

        Not that I understand why you want and external battery if you already have the internal battery, and are using the laptops shutdown feature.
        And external timer is all you need.

        Comment


        • #5
          Originally posted by OldSpark View Post
          Ah - you didn't say just a shutdown buffer...

          So a $20 double cigarette-packet sized battery is way overkill and too bulky. Rats!

          Oh well. It sounded to me as if you wanted a independence from the car battery (when the car isn't charging) and a graceful shutdown which - from your OP - was based on the laptops internal battery and the typical UPS signalling.

          Keep in mind that your external battery will probably be a higher voltage than your internal battery.
          It will need protection from over discharge.
          It will need to be charged.

          Not that I understand why you want and external battery if you already have the internal battery, and are using the laptops shutdown feature.
          And external timer is all you need.
          Sorry, I took your "2nd 12V battery" to mean a 2nd car battery.

          By using an external laptop battery as an intermediary power source, it can be charged by the alternator since the external batteries have charging circuits built-in. A typical external battery should give around 1 hour of usage assuming roughly 60-70W power draw but this depends largely on hardware and load.

          But now that you mention UPS, that is probably a better way to go about it

          Edit: This isn't a Laptop install. It's running a normal mini-ITX board, hence the custom battery.
          2004 HSV Clubsport M6
          Gear: i3 4130T, 8GB DDR3, ASRock Z87E-ITX, Noctua cooler, PicoPSU 150W, OpenUPS + SLA battery, 2DIN Samsung 7" screen with ITX enclosure, Win8 64 Pro

          Progress: [||||||| ] 80% - Planning done, Parts aqcuired, Benchtesting at 50%

          Comment


          • #6
            Again, I thought you were referring to "laptop batteries" which are just that - batteries - whether 3 cell, 6 cell, 24V whatever. They do not have chargers built in - that is provided by the accessory - be it mobile phone, laptop, whatever.
            And the DC supply they use is higher than their internal battery voltage (unless that have internal boosting - but they don't AFAIK).

            Not that I am aware of any "external [laptop] batteries (that) have charging circuits built-in" (though I am curious - where, and what price?) - but I don't see the point...
            IE - use the alternator to charge a 12V battery of your choice, feeding a dc-dc converter for 19V, else some higher than 19V battery charged by a dc-dc converter from the alternator (or 12V battery) and then presumably regulated for 19V output....?
            Unless they use 24V batteries, it would be very expensive (since 12V, 14V & 24V batteries are more common than (say) 20V or 22V batteries for a 19V DC supply....

            Comment


            • #7
              Have a look here:
              http://www.batterygeek.net/MacBook-L...y-Pack-s/1.htm

              They are designed to plug into the normal power jack on laptops to give an extra hour (or whatever the different sizes allow) or so of power. That particular site has various voltage output models etc.

              There's a few floating around on ebay which sit below laptops and are fairly thin. Basically they have a DC in and DC out and are fully self-contained (DC in charges the battery, DC out to the laptop is picked up as if it were just a normal mains) power connection.

              I'm currently looking into building my own system which does all this. Hopefully it'll be a 12V in, variable voltage out with internal battery plus shutdown controller features.

              An example of what I'm trying to do is the ASUS EEE Box B402. The B402 has a built-in Li-Ion battery and charge controller similar to a laptop which enables it to keep going when power cuts much like a laptop would. The trick is, finding how the UPS/power controller interfaces with the PC so that windows/linux/etc is aware of it and can act depending on power levels.
              2004 HSV Clubsport M6
              Gear: i3 4130T, 8GB DDR3, ASRock Z87E-ITX, Noctua cooler, PicoPSU 150W, OpenUPS + SLA battery, 2DIN Samsung 7" screen with ITX enclosure, Win8 64 Pro

              Progress: [||||||| ] 80% - Planning done, Parts aqcuired, Benchtesting at 50%

              Comment


              • #8
                You are describing a UPS - albeit DC output (with AC or DC input).

                I can't find any ASUS B402.

                As to the others - look at their price.
                I rest my case. (My 80WHr solution costs ~$60 of which the battery comprises $35.)

                Comment


                • #9
                  Originally posted by OldSpark View Post
                  You are describing a UPS - albeit DC output (with AC or DC input).

                  I can't find any ASUS B402.

                  As to the others - look at their price.
                  I rest my case. (My 80WHr solution costs ~$60 of which the battery comprises $35.)
                  Misspelt sorry, it's ASUS B204.

                  I don't expect to buy one of those batterys from that site, I'm attempting to build a similar system. Parts are way cheaper.
                  2004 HSV Clubsport M6
                  Gear: i3 4130T, 8GB DDR3, ASRock Z87E-ITX, Noctua cooler, PicoPSU 150W, OpenUPS + SLA battery, 2DIN Samsung 7" screen with ITX enclosure, Win8 64 Pro

                  Progress: [||||||| ] 80% - Planning done, Parts aqcuired, Benchtesting at 50%

                  Comment

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