Dell Venue 8 Pro and external batteries

Discussion in 'Dell' started by aginor, Dec 18, 2013.

  1. aginor

    aginor Pen Pal - Newbie

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    Hi guys, I was wondering if charging the tablet using an external battery was an option at all. These are a dime a dozen these days and you can easily get something like a 10,000 mah external battery with the size of a modern smartphone that outputs up to 3A/5V and plugs into microUSB ports of phones/tablets etc. I've been using one (I'm a frequent traveler) with my S3 without any issues for some time now (other than it takes a bit longer to get the phone charged compared to a wall charger and the phone battery never gets fully charged, but more like 70%), but that's still something, has anyone tried charging/running their V8Pro on an external battery?
     
  2. baxter

    baxter Scribbler - Standard Member

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    I just tried a RavPower 10,400mAh battery (2A out port) and the battery indicator showed no charging. Hooking
    the power adapter to the VP8 showed charging. This is very curious because I would have thought 2A to be sufficient.
     
  3. aginor

    aginor Pen Pal - Newbie

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    quite curious indeed, the ext battery i have (7000 mah, 2A out port) charges my Galaxy S3 and Asus HD7 without any issues, however refuses to work with my old TF101, I dropped by a local pcworld store after work today and tried it with the HP omni 10, Toshiba Encore and Asus T100 and it wouldn't charge any of these, so I have no clue why, but I kinda hoped... thats something that can make me go for the Miix2 if it's more external battery friendly, although I'd much rather get the V8Pro...
     
    Last edited: Dec 18, 2013
  4. Dc5e

    Dc5e Pen Pal - Newbie

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    I have a Sendy 5200mAh that only outputs 1A and it shows that it's charging. The cable or battery pack needs a short or have a resistor over the data lines for the tablet to start charging. I believe the cable provided with my battery does this.
     
  5. Ravynmagi

    Ravynmagi Scribbler - Standard Member

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    I just gave my New Trent 5000mAh battery a try, it only outputs 600 mA though. And it wouldn't charge, guess not a surprise. :)
     
  6. xrayzebra

    xrayzebra Scribbler - Standard Member

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  7. baxter

    baxter Scribbler - Standard Member

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    Well, I gave this another try. My battery indicates full. I used the cable supplied with the VP8 wall charger with the battery and still no indication of charge on the VP8. I checked the printed output of the VP8 wall charger and it shows 5V at 2A.

    I then tried another lower 6600mAh capacity battery that came with a bunch of different end connectors.
    I used the micro USB connector on this battery and it would begin charging the VP8 from either the 1A or 2.1A port.
    I then moved this cable and connector to the first battery and it also produced succesful charging from either port.

    So, it looks like almost any decent capacity battery will charge the VP8 if you have a CHARGING cable. As Dc5e points out, this must be a cable with the data lines shorted. I think there was mention of putting a 1.5K resistor across the data lines here,

    http://forum.tabletpcreview.com/dell/59328-venue-8-usb-power-same-time-11.html

    Also, this indicates to me that the USB data lines are shorted in inside of the VP8 wall charger since it uses a regular data cable which will not charge from a battery. I think the problem is that a regular USB can only output 500mA to remain within spec. and this is insufficient to start charging the VP8. Here are correct cables,

    Amazon.com : PortaPow Specialised 5ft 24AWG Charge Only Micro USB Cable for Blackberry, Xperia, HTC One, Google Nexus, Other Fast Charging Devices : Electronics Power Cables : Electronics
    Amazon.com : Red Band Smartphone and Tablet Quick Charge Cable USB Micro Right Angle RIGHT 18" Length : Computer Usb Cables : Electronics
     
  8. Beepcake

    Beepcake Pen Pal - Newbie

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    My Anker Astro Mini (3000mAh) charges it fine using the Ankers's own charging cable.
     
  9. xrayzebra

    xrayzebra Scribbler - Standard Member

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    Baxter: Thanks for putting those details together, it's helpful. So - I was never aware that some usb cables were specifically for data and some were specifically for charging, and I'm not even sure I am understanding that correctly now. Am I gonna find markings on the cables that tell me which they are? I've got dozens of cables and have no idea where any of them are from, having collected them over years. :)
     
  10. baxter

    baxter Scribbler - Standard Member

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    Ok, I just took a regular Micro USB data cable and turned it into a charging cable following these directions,

    Charge Only MicroUSB Cable

    As I write this, my VP8 is charging from a battery using a cable that wouldn't charge before, but now charges after being modified. I can confirm that all it takes is to cut the data lines (white and green), connect them together on the micro-B connector side and do not connect them on the USB-A side. The power lines (black and red) run run straight through. The soldering is a bit fiddly so It's probably less trouble to just buy one,

    Amazon.com : PortaPow Specialised 5ft 24AWG Charge Only Micro USB Cable for Blackberry, Xperia, HTC One, Google Nexus, Other Fast Charging Devices : Electronics Power Cables : Electronics
     
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