The Power Cable Hack

Discussion in 'HP Slate' started by TheWerewolf, Jan 29, 2011.

  1. TheWerewolf

    TheWerewolf Care for a bite?

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    Well, after hazarding a huge snow storm and braving insane drivers to get the last parts I needed, I'm finished the power cable hack.

    The good news is - it's insanely easy to do.

    First - the usual warnings. This is not an HP approved or sanctioned project. While unlikely, it is possible that it could damage your dock or your Slate. As well, it will require you handling a soldering iron and a voltmeter. If you are not comfortable with this - do not attempt this project.

    Also, you will be sacrificing an HP Slate power supply. I recommend getting a spare one first.

    Using this cable might violate your warranty (although I'm not sure about that.. clearly it violates the warranty of the power supply you're about to hack up...).

    The project - to make a cable out of a spare HP Slate power supply that can be used with an external battery and with third party power supplies (like the ultra compact laptop/netbook power supplies).

    The parts:

    [​IMG]

    1) Energizer "energi-to-go" or XPAL XP18000 battery. This runs around $150 and provides 3500mA output at up to 70WHrs. This is good enough to run a regular laptop for 6hrs (their claim) - so it should power the Slate for at least 9. With the 5hrs you get from the internal battery, you should see 11 - 15hrs of continuous use.

    Also, since the cable we're making matches the plug on the battery's charger, you can use the charger as a power supply for the Slate - eliminating an entire power supply, although the battery's charger at 3.45A is about 50% larger and heavier than the one that comes with the Slate.

    2) A 2.5mm female barrel socket with plastic shell and strain relief.

    [​IMG]

    Mode Electronics 31-152-1

    Should be available from any local electronics hobby shop, electronics parts shop or possibly from some Radio Shacks.

    2a) A 2.5mm male barrel socket with plastic shell

    [​IMG]

    If you want to make a direct connect cable, you'll need this instead of the female socket.

    3) If you don't have one - a soldering kit.

    [​IMG]

    4) A pair of scissors, an exacto knife or similar blade.

    5) A voltmeter.

    Now.. let's begin.
     
  2. TheWerewolf

    TheWerewolf Care for a bite?

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    Now, you have to make a decision.

    If you want to plug the cable directly into the battery and nowhere else, you can make it simpler by using the male plug. This lets you carry around fewer bits - just the slate, the cable and the battery, but it means you can't use the cable to directly power the Slate from the battery's charger - nor can you use it with third party adapters.

    If you want the male version, follow the exact same instructions, but with the male plug.

    This one will describe making the female version.

    Cut the 40 pin end of the cable just before the first bend, giving you a single unbent cable about 6" long with the 40 pin plug at one end and bare wires at the other.

    [​IMG]

    You'll see 6 wires - 3 white and 3 black. The white ones are +19V and the black ones are ground (0V).

    [​IMG]

    Disassemble the socket, then take the black plastic shell and thread the six wires in through the narrow end, then push the shell down to the 40 pin end. The part where the socket screws in should be pointing away from the 40 pin end.

    [​IMG]

    Strip the wires down to about 1/8" from the plastic sheath. Twist the three white wires together. Do the same with the three black wires.

    [​IMG]

    Fit the entire wire into the strain relief part of the socket (the long piece with the two tines) and thread the BLACK wires through the hole in the long piece on the outer edge of the socket and bend back, away from the socket. Trim the white wires until they fit in the hole in the pin in the middle of the socket.

    [​IMG]

    Now solder the two wires to their respective parts of the socket.

    Check your work with a volt meter. The center lead (the white wires) should only be connected to the center pin of the socket, and the black wires should only be connected to the shell part of the socket. There should be no shorts between the two.

    Crimp the two tines tightly around the plastic insulation sheath of the wire.

    Now, slide the plastic shell down and screw it on to the socket tightly.

    [​IMG]

    Now it's time for testing.
     
  3. TheWerewolf

    TheWerewolf Care for a bite?

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    The battery's charger or the AB05 plug included with the battery used with the 16v-20v cable works with this new cable.

    Do NOT connect the cable to your Slate or dock yet.

    Unscrew the plastic shell from the socket. Connect either the battery's charger, or the battery via the blue cable and the AB05 plug to the new cable. Using the voltmeter, confirm between 19V and 19.5V with the center being positive. If there is no voltage, disconnect and check your work as you have a short. If it's showing as -19V, you have reversed the white and black wires. Correct any mistakes and try again.

    If all is correct, screw the plastic shell back onto the socket and connect the 40 pin shell to the *dock*. The white light should light up. If not, recheck your connections as in the previous paragraph and try again.

    If ok, place your Slate on the dock. Remember, it will ONLY show orange if the Slate has less than 100% charge, so if the light doesn't go orange, check the battery charging icon, or use the Slate for a bit to discharge it then test again.

    If it's showing as plugged in and charging, voila. You're done. :)

    You can connect this to the dock or directly to the Slate.

    If you're inclined, you can add the male plug to the other half of the now sliced HP Slate power supply cable. This would allow you to reconnect the two parts together and go on using the official power supply when not on the road or when you don't want to use the battery.

    Enjoy!

    UPDATE: While it's a little odd feeling , you can use the blue 16-19v cable directly with the new cable, skipping thr AB05 converter. One less thing to carry. :)
     
  4. krelvinaz

    krelvinaz Systems Analyst

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    Great post and DIY project... Thanks.
     
  5. Bronsky

    Bronsky Wait and Hope. Senior Member

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    Brilliant!

    Bronsky:cool:
     
  6. Steve S

    Steve S Pen Pro - Senior Member Super Moderator

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    If it's just a question of 19V DC and ground, why are there three wire pairs?
     
  7. TheWerewolf

    TheWerewolf Care for a bite?

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    Current load and cable flex. It's sourcing 1A. A single thin wire would offer too much resistance and would heat up. A single thick wire would work, but then it would be very stiff.

    Also, there are several tie points in the 40 pin connector (in fact I think it's three for 19v and three for ground), this would make assembly simpler.
     
  8. Steve S

    Steve S Pen Pro - Senior Member Super Moderator

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    <<...several tie points in the 40 pin connector...>>

    ...Why would you deliver isolated voltages to three different points on the connector? Have you attempted to trace where they go in the dock's circuitry?

    <<...Current load...>>

    On the AC adapter side, are the three ground leads common? What about the three high leads?

    If they are, then you're likely right. But if they are not...
     
  9. heatlesssun

    heatlesssun Scribbler - Standard Member Senior Member

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    Great work Werewolf! I just got an XP 18000 the other day I intend to use for my EP121 but unfortunately the XP 18000 doesn't include a plug for the EP121 in the box but Energizer claims that if you send them the info on the plug needed they'll find a solution. You should contact Engergizer with this design so that they can offer this plug for the 500. Hopefully you can get some compensator for it.

    Thanks Again!
     
  10. Steve S

    Steve S Pen Pro - Senior Member Super Moderator

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    <<...Energizer claims that if you send them the info on the plug needed they'll find a solution...>>

    ...That's not a bad idea. It would certainly help those who are DIY-challenged...
     
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