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Compaq Portable III CMOS Battery

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    Originally posted by raisedabar View Post
    LTC-7P 3.5V 750 mAh Lithium (w/ PCB Termination) => this one is available now...
    LTC-7PMP 3.5V 1500 mAh Lithium (w/ PCB Termination) => this has to be order 5 weeks lead time...
    Does the mAh rating matter? Could I use the LTC-7P battery with my compaq portable III ?
    In theory, the 1500 mAh one will last twice as long as the 750 mAh one.

    Originally posted by raisedabar View Post
    anyone have a drawing to show where to solder the diode(s) and resistor(s) in relation to the batteries...
    For a guide, see the bottom half of the diagram [here].
    Because the diode, resistor, and battery are in series, they can have any order. What is important is the polarity.
    If there are multiple resistors, then they may be parallel to each other.



      Thanks for the diagram! I am a newbie to electronics and its terminology... but pictures speak a thousand words for me. I was going for the 750 mAh ones because they were suppose to be the same as the 1500 mAh w/ less mAh. But after they photos (which stated that they might not be the exact representation of the actual battery looks slightly wider than the original batteries which means they won't fit in the original black casing. Not sure if I could use it anyway it looks like they stuck the two batteries in there with the diode and resistor and then poured clear glue/resin/something... not sure if I can save the case... then blows. I wish I could solder a modern battery holder in there like the newer computers that take the coin batteries (i.e. CR2032) but the coins only have a mAh rating of 240. I guess its obvious I have no electronics background what so ever =)
      Last edited by raisedabar; September 9, 2013, 11:00 AM.


        Revisiting this again. Just purchased a LTC-7PMP battery (w/ diode and resistor) this is the latest version of the original battery specs are the same... but we'll see when I get it. If its a match then I will order more... only thing is, the battery costs as much as what I paid for my whole computer =)


          Hey James,
          Its funny I saw reply and look at the dallas DS12887 battery and it looked like a rom chip, nothing like my battery (have several Compaq Portable IIIs), but recently, I purchased a cp3 and it had the dallas battery on it instead of the eagle picher brand. It was also on the right side of the motherboard instead of the center left like the others. Maybe there were a couple versions of the boards, I will have to investigate...