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    GH2 Power - specs, tests, DIY
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    Senior Member keylight's Avatar
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    ---------------------------------------------------------------------
    UPDATE #2: I now use the incredible Tekkeon MP3450i R2.
    Over 10 hours on a charge. More details in Post #201.
    ---------------------------------------------------------------------
    UPDATE: In Post #152 guyburns put together a
    GREAT summary of what we know as of 5/25/2011.

    ---------------------------------------------------------------------






    There's a lot of information in various places on powering the GH2. I thought it might be useful to put links in one place. Hopefully this will help others in the future.

    First, there's a DIY DC Adapter (DMW-DCC8). The original idea is from Tyampel. Another nice variation is from g.l., who also had some useful tips.

    GH2 DIY dc adapter (2 of 5).jpg

    UPDATE: And now we know what the inside of a Panasonic DMW-DCC8 looks like. Full post here

    DMW-DCC8-board-back.jpg

    DMW-DCC8-board-front.jpg

    Then, there is the DIY DC Power Source. I made one of these and then ran it for 8 hours non-stop: Video Here

    test.jpg

    I used an 8.4v 4500mAh 7 cell Ni-MH flat battery for this test.

    Below is a photo showing the bottom of the Panasonic AC Adapter (DMW-AC8PP). I metered the adapter and it runs at 8.79v. When I connect the Adapter to the camera via my DIY DC adapter, the voltage drops to 8.70. The Amperage is 740mA, even though the adapter says the output is 1.2A. See posts later in this tread for a discussion....


    adapter_bottom.jpg

    I've scanned the manual, but the site isn't allowing me to upload. Anyone know if there's a pdf file size limit (it's approximately 1.2MB)?


    Last Edit changes: Added update to the top. Removed some quotes from later in this thread, as the link in the update summarizes everything best.
    Last edited by keylight; 01-08-2012 at 07:41 PM.


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    Senior Member g.l's Avatar
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    Thanks for collecting it all.

    The one missing piece of the puzzle is what voltage the adapter actually outputs - could you test that?


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    Senior Member keylight's Avatar
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    Quote Originally Posted by g.l View Post
    Thanks for collecting it all.

    The one missing piece of the puzzle is what voltage the adapter actually outputs - could you test that?
    Good idea. The adapter meters 8.79v. When I connect the Adapter to camera via my custom DC adapter, the voltage drops to 8.70.

    Edit: The Amperage is 740mA, even though the adapter says the output is 1.2A. This seems strange. And when I try to check the Amps with the Adapter hooked up to the camera, the camera shuts off (camera runs fine otherwise).
    Last edited by keylight; 04-14-2011 at 05:20 PM.


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    Senior Member g.l's Avatar
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    Great, this is the crucial bit. We now know that anything up to 8.8V at least is safe. Also interesting that it's rated for 1.2A.

    I've suggested cheap 9V/1A adapters as suitable replacements. Looking at this all again:

    - 9V is probably safe, but there's no way to be 100% sure (I will run my DC converter at around 8.6V).

    Has anyone run the GH2 at 9V or higher for a long time?

    - 1A is safe, but is it enough? The 1.2A rating may indicate that under exceptional circumstances the body needs a bit more juice (maybe only in tiny bursts). Or it's also possible that Panny is deliberately obfuscating so users don't look for common 9V 1A replacements.


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    Senior Member keylight's Avatar
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    Quote Originally Posted by g.l View Post
    Or it's also possible that Panny is deliberately obfuscating so users don't look for common 9V 1A replacements.
    Here's an interesting note from Tyampel in another thread, which may help explain the 740mA output I got on the adapter....

    Quote Originally Posted by tyampel View Post
    Thanks for posting the picture of the adapter. It is interesting to note that it differs from the one for GH1. On the GH1 it says:

    INPUT/ENTREE:

    110v - 240v ~ 50/60 Hz 0.3A

    OUTPUT/SORTIE:

    9.3V = 1.2A (DIGITAL CAMERA/APPAREIL PHOTO NUMERIQUE)

    8.4V = 0.65A (CHARGE).

    Perhaps the ommission is deliberate to confuse the DIY people as I don't think the cameras differ in that regard.


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    We have a standard product called vDoubler which is used to power the HD monitors and other accessories. It outputs 12V up to 2A which is more than enough power to run the GH2; we could set the output voltage to 9.2V instead of 12V and add the right connector, so it will be like the DMW-AC8PP AC adapter from the camera point of view. This adapter plate would power the GH2 camera for many hours using a DV battery (either Pan, Sony, or Canon). The problem is we do not own the camera, so can not test the configuration. If somebody is interested to be a beta tester for us, please IM directly so we can discuss logistics.


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    Senior Member keylight's Avatar
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    Looks nice, but the price seems a bit high for a single output. The RC battery goes for about $40 and for another $5 in parts you can make a little adapter cable.

    But it's something for people to keep in mind if they have a whole bunch of 7.2v batteries at their disposal. Thanks for posting it.

    What would be really nice is if you came up with a solution that would allow you to plug multiple devices (that have different power requirements) into a single power source. Something like your adapter but with multiple switchable outputs (and a variety of adapter cables for different devices.

    Quote Originally Posted by adolgin View Post
    We have a standard product called vDoubler which is used to power the HD monitors and other accessories. It outputs 12V up to 2A which is more than enough power to run the GH2; we could set the output voltage to 9.2V instead of 12V and add the right connector, so it will be like the DMW-AC8PP AC adapter from the camera point of view. This adapter plate would power the GH2 camera for many hours using a DV battery (either Pan, Sony, or Canon). The problem is we do not own the camera, so can not test the configuration. If somebody is interested to be a beta tester for us, please IM directly so we can discuss logistics.


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    It isn't strange that the voltage changes 90mv. That's just loss through the output filtering of the adapter. It also is NOT strange that the unit only draws 740mA from a 1.2A source. All the specs you read are always spec'd at full load. What you see is what we call "floating voltage/current". Without the load, those numbers can be all over the place.

    Generally, designers just overdesign power supplies to meet instantaneous demand, or simply because they can, have certain parts available, just copied a manufacturer's design or they might have even simply reused a design from something else.

    It's no attempt to obfuscate anything, I can guarantee that.

    I design battery chargers amongst other power devices at my day job and this is just business as usual.

    EDIT:

    OUTPUT/SORTIE:

    9.3V = 1.2A (DIGITAL CAMERA/APPAREIL PHOTO NUMERIQUE)

    8.4V = 0.65A (CHARGE).
    That difference is due to the loading of the battery vs. the loading of the camera body. The battery, when fully depleted, needs to be charged with a constant current, at a certain rate (hence the different voltage and current), until around 10-25%(depending on the cells) of it's capacity and then constant voltage charged to withing a couple mV of it's full capacity.

    Allowing the cells to be charged too quickly or with too much current can alter their chemistry and damage them, aside from making them dangerous.

    Anyway, I took a peek inside the GH1 charger and it has a switcher to bring down the 120vac to around 10V and then a separate battery circuit. The camera taps off the ~10v circuit. So that's why you can get different powers for the battery and body.
    Last edited by Svart; 04-14-2011 at 06:58 PM.


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    On another note, I've been intrigued with all the fuss over second sourced batteries. I bought two ebay specials, which surprisingly claim to be LI-ion complete with protection circuitry and everything. I plan on taking one apart to see what's actually inside and if it actually is what it says it is. (I'll also use the body of it to make a DC adapter)

    The second one I'll use if the first one is actually decent.

    Once I get them, I'll post my findings and the link to the batteries if I think they are safe enough for use.


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    Just an FYI...the 9 volt power supply I tried that didn't work was listed at 1200mAh. New one coming in is the one from Amazon listed in one of the threads. I believe it's rated at 2 A. Soon as I get it I'll report back.

    Mark

    ps Thanks for collecting all this keylight!!


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