External Battery for Surface Pro?

Discussion in 'Microsoft' started by dgeffs, Feb 12, 2013.

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  1. JanAWD

    JanAWD Pen Pal - Newbie

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    Here are photos of the Sanho Hyperjuice 2 Battery connected to the Surface Pro via the Magic Box hacked to the adapter cable. It does recharge but VERY slowly......

    MagicBox.jpg
    MagicBox2.JPG
    MagicJuice2Connected.jpg
     
  2. xterrapro

    xterrapro Pen Pal - Newbie

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    Nice. Interested to hear from dead - how long this will power/charge.
     
  3. JanAWD

    JanAWD Pen Pal - Newbie

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    Well, after leaving it plugged in for awhile it seems that it does not charge, even though the battery indicator shows it charging. It may be that sense/detect pin. I am sending the cable to Mike Gyver's Store to see if he can adapt the cable as he does with the MagSafe cables.
     
  4. 15590841

    15590841 Pen Pal - Newbie

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    Hello guys,i am new here and i just made an account to keep track of this thred as i have to decide between a MS surface pro or a S-Ativ smart pc pro. The features of both are amazing but i need at least 8hs of battery life. I saw a couple of chargers for the MS surface pro rated at 12V 2.0A which means a normal external battery will be useless,but there are some external batteries that can deliver 5V~12V~16V~19V (manual adjustment) and even some of them will adjust voltage automatically :thumbsup: and they can also deliver more than 2.0A (at 12V).... :rolleyes: so...the big question is.... if i buy an extra charger,cut the wire,solder it to a usb cable (as one of you said before) i will have an usb to magsafe cable (following the pins provided in this thred [​IMG] ) :cool: Then i would use an external battery rated at 12V 2.0A(or more Amps),connect the usb cable,connect the magsafe-like to the surface pro and we are good to go :D ....well at least i think so...correct me if i am wrong,also the ones who are experimenting with the magsafe-like pins please update this thred because i am very interested ..... nvm just download the image i made explaining all this... :p bateria externa.jpg
     
  5. dgeffs

    dgeffs Pen Pal - Newbie

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    Just got around to testing the charge with the Energi-To-Go battery and it charged to 100% in a bit less than 2 hours starting at 38%. It appears this battery will charge the unit multiple times based on the battery indicator. The center pin is unused in my connector.
     
  6. bjornb

    bjornb Pen Pal - Newbie

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    I havent received my Pro yet, but I am planning to extend the batterytime when needed with my Tekkeon myPowerAll battery.

    I've bought a Surface RT power supply locally, cut the cable and did some measurements on it:


    I am measuring 12V between several cables:
    12V between red (+) and black (gnd)
    12V betwen red and white
    12V between red and blue

    Can anyone confirm the red -> white/blue voltages on your chargers?

    Since I have no Surface tablet yet these measurements are no-load values. I am wondering/speculating wether there will be a difference to the blue and white related values when connected..

    BTW, I cant see a led element on the end of the connector on my RT charger, is it visible when not lit on yours?
     

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    Last edited by a moderator: May 18, 2015
  7. Steve S

    Steve S Pen Pro - Senior Member Super Moderator

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    <<...I am measuring 12V between several cables...>>

    ...This is all interesting information, but I would suggest that a more "informed" way to approach this is to cut open the power supply itself and look at the circuit board geometry. That should quickly tell you what wire is high-side, what wire is ground and what the other wire(s) are intended to do...
     
  8. bjornb

    bjornb Pen Pal - Newbie

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    Yes, that is also interesting and may help. I can see there is a seam on one side, maybe it can be opened without too much damage...

    The internals of the magnetic connector at the end of the cable (perhaps the white cable is connected to one side of the led?) and the connector on the surface is also interesting:
    [​IMG]
    (Where does the 'DET' connector go? To the motherboard or is it part of a simpler circuit on the connector only?
     
    Last edited: Mar 6, 2013
  9. bjornb

    bjornb Pen Pal - Newbie

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    I've worked on the RT charger today. Opened it up, but it didnt tell me much by looking at it (too complex unless I spend some time with it).

    Opened up:
    2013-03-07 01.39.07.jpg

    DC connectors:
    2013-03-07 01.50.16.jpg

    Closeup:
    2013-03-07 01.46.19.jpg

    I've connected some Anderson Powerpole connectors to both ends so I can still use the RT power supply. I have so far only connected the red/black cables.
    2013-03-10 01.10.41.jpg


    I also wanted to see if it was possible to use the RT charger as a small generic 12V powersupply but that did not work initially. I connected a test load to the red/black cables but it just deactivated (test load was 33ohms, ~4W load @12V). I then speculated whether one or both of the other cables was needed to activate the charger. I found some resistors and then connected varius cables together to see if anything happened. If I connect the yellow to red the charger activates. I tried with different resistor values to find the highest possible value to activate (higher resistance -> less current). 1kohm was too much, and at about 700ohm it activates (the 'control current' is about 14mA). Resistors shown below is two 1kohm in parallell in series with 180ohm.
    2013-03-10 01.00.29.jpg

    Next step is looking into the other end and see if I can actiavate the white led on the magnetic connector.
     
    Last edited: Mar 9, 2013
  10. Steve S

    Steve S Pen Pro - Senior Member Super Moderator

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    <<...too complex unless I spend some time with it...>>

    bjorn: (I meant to comment earlier, but was preoccupied with another subject.) At first blush, the RT AC adapter is wildly more complicated than a simple buck regulator would warrant. The implication is that it's doing much more than simply supplying 12 volts for charging. The question is: What would that be?

    Is it possible that Microsoft has relocated the usual charging control and safety circuitry for the Li-Ion battery pack from the RT to the adapter? If so, that would make the "sense" line not just some sort of authentication channel, but potentially a critical safety channel, as well! Put differently, is it possible that without a proper Sense circuit feedback, connecting an RT (and maybe a Pro?) to a 12 V source could cause the Li-Ion battery to overcharge or fail (either benignly or catastrophically)?

    It would be instructive if you could identify any of the ICs or at least list the ID numbers on any of the IC's. In particular, are any of them marked "Maxim?" That's a popular brand of charging controller and the type of part that would be used in a Li-Ion charging / safety circuit...
     
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