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ITPS + 3.5" Hard Drive == Death?

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  • ITPS + 3.5" Hard Drive == Death?

    I think I read in a *VERY* long thread in this forum once (can't seem to locate it anymore) that systems with 3.5" hard drives won't shutdown properly with the ITPS regulation (due to the 12V line dropping to 10.x volts when the engine is off?). Anybody want to verify that this is true (and that I'm not just butchering things together after hours and hours of reading?).

  • #2
    Originally posted by soybeanstorm
    I think I read in a *VERY* long thread in this forum once (can't seem to locate it anymore) that systems with 3.5" hard drives won't shutdown properly with the ITPS regulation (due to the 12V line dropping to 10.x volts when the engine is off?). Anybody want to verify that this is true (and that I'm not just butchering things together after hours and hours of reading?).
    Read it again - http://www.mp3car.com/vbulletin/show...highlight=ITPS
    Laidback


    The ultimate CarPC - Wow!

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    • #3
      haha. good stuff. I re-read all *5* pages of that thread.. A simple, "You're on the money" would've sufficed, but what's the fun in that, right?

      Anyhow, I'll summarize it up for any other newcomers.. maybe it'll save someone some time:

      Using ITPS w/regulation:
      - Drops 12v rail to ~10.x Volts when car is off, as a result:
      - Don't use 3.5" drives when using ITPS w/ regulation
      a) The 10.x volts on the 12v rail causes the HD to flip out
      (when you turn your car off.. so shutdown controller doesn't really
      have a chance to do its thing with the flipped-out HD)
      - 2.5" Laptop HDs are fine since they only use the 5V rail
      - ITPS regulation only allows a maximum of 60 Watts through.
      - ITPS w/ regulation + PW-70A? Still only 60 Watts. The weakest link
      ruined the party for everyone. boooooooooooo

      I hope I got that right. Seasoned car PC guys, feel free to correct anything I may have gotten wrong.

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      • #4
        Originally posted by soybeanstorm
        haha. good stuff. I re-read all *5* pages of that thread.. A simple, "You're on the money" would've sufficed, but what's the fun in that, right?.
        Well, we had to read it! Not only *5* pages but over *5* weeks!!


        Originally posted by soybeanstorm
        Anyhow, I'll summarize it up for any other newcomers.. maybe it'll save someone some time:
        'Cause it's a case of life or death that they get their car pc installed??
        Laidback


        The ultimate CarPC - Wow!

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        • #5
          Originally posted by Laidback
          'Cause it's a case of life or death that they get their car pc installed??

          You're right on the money!

          Comment


          • #6
            If i have a 3.5" hd in an external enclosure, its 12v line hooked up to a relay controlled by the itps sort-of, will that be unhealthy for hte drive at all?

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            • #7
              If the 12v line going to the HDD is unregulated then it could be...what do you mean 'controlled by the ITPS sort-of'?
              Laidback


              The ultimate CarPC - Wow!

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              • #8
                So if you use a laptop hard drive, the shutdown controller on the ITSP will work fine. What about surviving the crank?

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                • #9
                  Originally posted by morgant6911
                  So if you use a laptop hard drive, the shutdown controller on the ITSP will work fine. What about surviving the crank?
                  It's possible in theory depending on which PSU and system board you use but I think it depends on whether the PSU or system board monitors the 12v rail.
                  Laidback


                  The ultimate CarPC - Wow!

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                  • #10
                    I have a Seagate 5400 U Series disk, an ITPS and a PW-60. The hard drive is the least of my problems! Seems to work ok when the ignition is off, haven't tested the voltages with the car off, but they've been screwey all along. My 3.3V rail sits on about 2.4V when the car's running.. 12V is spot on mostly, 5V is between 4 and 5V. The system runs okay most of the time, car on or off, but it tends to reboot randomly sometimes when I do a heavy read on the hard drive (especially when the ignition is off) and reboots often when going into windows or coming out of hibernate. I'm attributing that to the power good line dropping.

                    The ITPS/PW60 combination has been nothing but trouble for me. When it works, it's ok. The rest of the time it makes me want to take it out and smash it on the road....

                    Anyway I've ordered an Opus 150W to replace it, and I'm also going to use thicker grade wire on that. Fingers crossed. Power has been the second most expensive part of the project, second only to the Xenarc...
                    89 Celica, CarPC installed, 1st bday :)
                    http://www.fishy.net.nz/carpc/
                    • MediaEngine
                    • Epia V8000
                    • 80GB WD 7200RPM HD
                    • Xenarc 700TS
                    • SB Live
                    • Opus 90W
                    • CIMR100 remote
                    • Deluo serial GPS
                    • D-Link USB radio wired to power antenna

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                    • #11
                      Originally posted by OrangePeel
                      The rest of the time it makes me want to take it out and smash it on the road....
                      Laidback


                      The ultimate CarPC - Wow!

                      Comment


                      • #12
                        What power supplies actually regulate the 12v?? I was thinking of a PW-70A + ITPS + a 3.5", but i don't think its regulated.
                        My Mazda 3s

                        My Mazda 3s on Car Domain

                        [||||||||||||||||||--] (90%)

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                        • #13
                          the PW60/70 etc don't regulate the 12v, since they're designed to run off an AC adaptor that feeds 12V straight through. It just passes 12V power through.
                          The ITPS has the option of using its LDO 5A regualator to make pure 12V from the car power when the car is running, but it's a stepdown-only regulator, and with a ~0.5v dropout, so if you turn the car off, and it's at 12V, 11.5v is the maximum it will feed the PW70, which will only affect the 12V rail..

                          The most major problem is of course when you're cranking, your 12V rail will hit about 7-8V, which will trigger power protection circuitry in the HD if it has it.. Or else the HD will just stop responding until the motor spins back up again (if it's old).

                          Ituner told me in an email that their PW60+ITPS should survive cranking... But no, not without a tank circuit.
                          89 Celica, CarPC installed, 1st bday :)
                          http://www.fishy.net.nz/carpc/
                          • MediaEngine
                          • Epia V8000
                          • 80GB WD 7200RPM HD
                          • Xenarc 700TS
                          • SB Live
                          • Opus 90W
                          • CIMR100 remote
                          • Deluo serial GPS
                          • D-Link USB radio wired to power antenna

                          Comment


                          • #14
                            PW-80 regulates 12V, and has a wide input voltage range, but sadly it bottoms out at 11V.

                            Also, the regulated 12V is no powerhouse - only 2.5A.
                            SeeYa! -Jim-

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                            • #15
                              based on their graph, it kinda says 60a and 70a are regulated, is that correct?
                              My Mazda 3s

                              My Mazda 3s on Car Domain

                              [||||||||||||||||||--] (90%)

                              Comment

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