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Powering GH2
  • I have important question.

    Is it enough to supply 7.2V from external battery.
    Or 8.4V as in original power supply is required?
  • 381 Replies sorted by
  • Just found tyampel citation - "you need to feed the coupler with 8.4 to 9.3 volts. Lesser voltage will result in a message "This battery cannot be used"."

  • At least 8.4V. But other users who have conducted tests say 9+ is ideal.
    Also strange is that when I shoot in slow motion mode, it would say 'this battery cannot be used', but 24p is fine.
  • @ed_lee83

    I formed similar opinion about this.
    It looks like GH2 uses voltage measurement to decide it is AC or battery.
    And battery must always pass their complicated checks.
  • Does anybody know of a way to use 7.2v and upconvert to 8.4v, or a way to use 12v and downconvert to 8.4v?
  • Upconvert of CC is complex. Downconvert from 12V to 8.4 V can be done with many simple electronic circuits, but anyway need a bit of experience. If you want, I can attach some electric diagram for this.
  • Do you know how many amperes is the load of GH2 (maximum)?
  • don't know, but won't it just pull what it needs? I've been trying to find the specific amperage of the panasonic adapter, but I can't seem to find the specs anywhere. I have experience building and soldering, just don't know how to actually design the circuit. I was just thinking about doing it with resistors, since the drop is so small, and it would be running off a 12 volt battery.

    It would be awesome if you could attach a diagram.
  • If the load is not more than 3A, this circuit (25$): is good for this use (downconvert 12V to 8.4). If you want a switching conversion (=optimum efficiency) a circuit based on National Semiconductor LMZ14203H - can be used for maximum 3A.
    The last switching circuit can also upconvert from 7.2 to 8.4.
  • With the LM14203H, you can use the circuit on the datasheet here:
    The resistence to be used are: RFBB=3,9k RFBT=37k ohm - if you want best precision, you can use a trimmer from 0 to 5K with a 1k resistence series as RFBB, and regulate output voltage with a multimeter.
    Rent and Renb set the minimum voltage for input - under this voltage the circuit go off. For example, if we decide 10 V minimum voltage input, resistence value will be Rent=39K Renb=5,2k.
    Good value for Css is 4700 pF (start in 0,5 ms) - Cout = 47uF - Cin =22 uF - Ron 180k- Cff 0,022 uF (as indicated in circuit diagram).
    I have in my previous post made ​​a mistake, this circuit can't up convert, only downcovert.
  • Can seriously recommend one of these for powering the GH2.

    Have tested and it does output a pretty stable 9V - works very well connected up to the DC coupler (or you can make your own). At 8500mAh it lasts over 7x as long as the official battery for 1/3 the price. Plus you can power USB devices and have a 12V for a monitor/light - all the outputs can be used at the same time. You could use a splitter if you want more devices. Mounting is a bit difficult, though easier than an RC car battery. I made a mounting plate for mine, glued on, which can then be screwed onto a rails block/flash hotshoe. Only thing missing from it is a charge meter.

    Other than that, its really hard to find anything better that comes close to the price.
  • @Ptchaw

    Thanks for suggestion.
  • @Ptchaw
    Can you post a few pics? This looks really cool.
  • @Ptchaw on the ebay page says that comes "With working indicator", what is that mean exactly as you state that it lacks charge meter?
  • @Ptchaw

    What are the dimensions of the battery? What did you use to make the mounting plate?
  • @Ptchaw first ahha you have become a little star (:
    second, you mention that we can make our own dc coupler, do you have some diagrams to share? im´mean i´m truly interested in making my own, but i´m not sure if inside the coupler there is a chipset or something
  • @lolo Wasn't my idea, but thanks :) The indicator is just an led which lights up when its on/charging. I was hoping for some sort of charge meter that shows you how much capacity is left; you loose the power meter on the GH2 when using the coupler.

    You can buy a DC coupler for about $40 - search DMW-DCC8 on Amazon/eBay. People made their own out of wood/mouldable plastic when they were out of stock - it's just a battery sized block with contacts on and a lead. Unless you are very hard up/cannot get one shipped I would just buy one.

    The 9V lead with the battery won't quite fit into the coupler, I found an spare male plug from a transformer and soldered that on to the lead. If you do any DIY soldering make sure the polarity is right; you can kill your GH2 if it is the wrong way round. You should just be able to get an adapter that converts the connecters for transformers, though I'm not sure what size the coupler takes.

    @Roy_Batty Dimentions are 126mm x 73mm x 25mm Initially cut a mounting plate out of wood, but I'm going to redo it with perspex. For now its cable tied to a rails block. The rails block is just a spacer for 2 x 15mm rails, with M4 threads on the bottom. My plate just has recessed holes for screws to screw into the rail block, to give a large surface area to glue the battery onto. Will post pics when done :)
  • Thanks Ptchaw, excellent information! Just to make sure and to summarise what's needed:
    1. Battery:
    2. DC Coupler from Panasonic or self-created
    3. Connector adapter

    Is that correct? Is there any risk of possible bricking of the GH 2, or is this only if you reverse the polarity on the plug?

    You mention 7 x battery time, have you timed this, or calculated this?
  • @ptchaw,

    Is there a polarity switch on the connector/adapter tip -- the end you plug into the DC coupler?

    Edit: Ptchaw, I just re-read your post where you discuss having to modify the tip. Never-mind.
  • @Ptchaw thank you! i love you! jajajja
    :D you have solved a huge problem for me!
  • I came across this and I wasn't sure if anyone has seen it. This system lets you use standard prosumer camcorder batteries with your GH2. If you have a rig and mount place this is an ideal set up. And its reasonably priced.

    500 x 373 - 24K
  • Oh and apparently Switronix finally decided to show us GH2 users some love too....
    736 x 702 - 101K
  • @Retina That is correct. You should easily be able to find a transformer adapter for No. 3, but I am not sure of the type.

    The GH2 coupler has the polarity marked on it; the outer ring is negative, with positive on the inside pin. So long as you stick to that, and 9V you're fine. I'd recommend checking it with a circuit tester just to be sure.

    The kit battery is 1200mAh, the eBay battery is 8500mAh, so assuming the specs are accurate it should last over 7x as long. Have yet to check this though. At some point I'll see how long I can record for with it. I'm not sure what will happen when the battery runs out though (haven't had it happen yet). Depending on the voltage, the camera may switch off, or report that the battery is incompatible and (hopefully) gracefully stop recording.
  • I can't find it now, but I remember reading a thread (perhaps on in Gear category) where someone was saying a Li-Ion battery can drop quite significantly in voltage while it's discharging. Once you go below 8.4v (?) the GH2 realises it's on a third party battery (and not AC) and refuses the power, but the battery can still have half it's charge available.
  • Why do all this risky bs>? Just wait for proper battery solutions...the switronix cable and battery is a much better idea if you ask me.I for one am not gonna "brick" my camera on some hacked battery -
  • @No_SuRReNDeR It is not "risky bs". So long as you do not do anything stupid, like give your GH2 12V or the wrong polarity, you won't brick your camera. The battery provides a stable 9V, hardly much more than 8.4.

    I only did soldering because I had the right connector and didn't want to wait for one to be shipped. You do not need anything other than the battery, the coupler and a connector, no soldering required. It is not a "hacked battery", it is no different from using a Switronix battery and lead.

    The Switronix you linked to still has the same problems regarding battery charge; you loose the indicator on the GH2. It also costs over 5x the price of this solution for the cable alone, hardly an affordable solution for everyone.